WEBVTT Kind: captions Language: en 00:00:00.000 --> 00:00:02.690 align:start position:0% this<00:00:00.510> talk<00:00:00.719> is<00:00:00.870> about<00:00:00.960> the<00:00:01.140> new<00:00:02.010> you'll 00:00:02.690 --> 00:00:02.700 align:start position:0% this talk is about the new you'll 00:00:02.700 --> 00:00:06.519 align:start position:0% this talk is about the new you'll optimizer<00:00:03.480> and<00:00:04.069> I<00:00:05.069> want<00:00:05.339> to<00:00:05.430> start<00:00:05.670> in<00:00:05.850> a<00:00:06.000> good 00:00:06.519 --> 00:00:06.529 align:start position:0% optimizer and I want to start in a good 00:00:06.529 --> 00:00:08.299 align:start position:0% optimizer and I want to start in a good tradition<00:00:07.529> I<00:00:07.620> want<00:00:07.770> to<00:00:07.830> start<00:00:08.040> with<00:00:08.250> a 00:00:08.299 --> 00:00:08.309 align:start position:0% tradition I want to start with a 00:00:08.309 --> 00:00:11.330 align:start position:0% tradition I want to start with a definition<00:00:08.700> what<00:00:09.120> is<00:00:09.150> an<00:00:09.330> optimizer<00:00:10.340> an 00:00:11.330 --> 00:00:11.340 align:start position:0% definition what is an optimizer an 00:00:11.340 --> 00:00:13.669 align:start position:0% definition what is an optimizer an optimizer<00:00:11.790> is<00:00:11.910> a<00:00:12.330> piece<00:00:12.900> of<00:00:13.049> software<00:00:13.380> that 00:00:13.669 --> 00:00:13.679 align:start position:0% optimizer is a piece of software that 00:00:13.679 --> 00:00:15.799 align:start position:0% optimizer is a piece of software that takes<00:00:14.309> another<00:00:14.910> piece<00:00:15.120> of<00:00:15.150> software<00:00:15.570> a 00:00:15.799 --> 00:00:15.809 align:start position:0% takes another piece of software a 00:00:15.809 --> 00:00:18.920 align:start position:0% takes another piece of software a program<00:00:16.260> as<00:00:16.410> input<00:00:16.800> and<00:00:17.480> transforms<00:00:18.480> it<00:00:18.690> into 00:00:18.920 --> 00:00:18.930 align:start position:0% program as input and transforms it into 00:00:18.930 --> 00:00:22.730 align:start position:0% program as input and transforms it into a<00:00:19.500> new<00:00:19.650> piece<00:00:19.890> of<00:00:19.920> software<00:00:20.750> that<00:00:21.750> hopefully 00:00:22.730 --> 00:00:22.740 align:start position:0% a new piece of software that hopefully 00:00:22.740 --> 00:00:25.160 align:start position:0% a new piece of software that hopefully requires<00:00:23.100> fewer<00:00:23.519> resources<00:00:23.820> or<00:00:24.210> at<00:00:24.330> least<00:00:24.539> not 00:00:25.160 --> 00:00:25.170 align:start position:0% requires fewer resources or at least not 00:00:25.170 --> 00:00:29.269 align:start position:0% requires fewer resources or at least not more<00:00:25.800> and<00:00:26.869> is<00:00:27.869> semantically<00:00:28.529> equivalent<00:00:28.769> so 00:00:29.269 --> 00:00:29.279 align:start position:0% more and is semantically equivalent so 00:00:29.279 --> 00:00:31.279 align:start position:0% more and is semantically equivalent so it<00:00:29.550> means<00:00:29.760> it<00:00:29.939> does<00:00:30.359> exactly<00:00:30.660> the<00:00:30.900> same<00:00:31.050> thing 00:00:31.279 --> 00:00:31.289 align:start position:0% it means it does exactly the same thing 00:00:31.289 --> 00:00:35.060 align:start position:0% it means it does exactly the same thing and<00:00:32.809> both<00:00:33.809> of<00:00:34.050> these<00:00:34.200> components<00:00:34.739> of<00:00:34.980> the 00:00:35.060 --> 00:00:35.070 align:start position:0% and both of these components of the 00:00:35.070 --> 00:00:37.250 align:start position:0% and both of these components of the definition<00:00:35.579> allow<00:00:35.940> for<00:00:36.270> some<00:00:36.480> kind<00:00:36.870> of<00:00:37.050> slack 00:00:37.250 --> 00:00:37.260 align:start position:0% definition allow for some kind of slack 00:00:37.260 --> 00:00:40.010 align:start position:0% definition allow for some kind of slack so<00:00:37.590> both<00:00:38.129> the<00:00:38.670> resources<00:00:39.149> and<00:00:39.270> the<00:00:39.750> cement 00:00:40.010 --> 00:00:40.020 align:start position:0% so both the resources and the cement 00:00:40.020 --> 00:00:41.389 align:start position:0% so both the resources and the cement equivalents<00:00:40.469> but<00:00:40.649> we<00:00:40.770> will<00:00:40.890> touch<00:00:41.129> on<00:00:41.250> that 00:00:41.389 --> 00:00:41.399 align:start position:0% equivalents but we will touch on that 00:00:41.399 --> 00:00:44.930 align:start position:0% equivalents but we will touch on that later<00:00:41.930> let's<00:00:42.980> see<00:00:43.980> an<00:00:44.070> example<00:00:44.160> so<00:00:44.640> this<00:00:44.789> is 00:00:44.930 --> 00:00:44.940 align:start position:0% later let's see an example so this is 00:00:44.940 --> 00:00:48.619 align:start position:0% later let's see an example so this is solidity<00:00:45.329> code<00:00:46.399> that<00:00:47.399> computes<00:00:47.789> the<00:00:48.600> square 00:00:48.619 --> 00:00:48.629 align:start position:0% solidity code that computes the square 00:00:48.629 --> 00:00:53.680 align:start position:0% solidity code that computes the square of<00:00:49.440> the<00:00:49.920> input<00:00:50.070> number<00:00:50.520> and<00:00:52.039> it<00:00:53.039> uses<00:00:53.219> the 00:00:53.680 --> 00:00:53.690 align:start position:0% of the input number and it uses the 00:00:53.690 --> 00:00:57.650 align:start position:0% of the input number and it uses the exponentiation<00:00:54.890> operation<00:00:55.890> which<00:00:56.789> is<00:00:56.820> quite 00:00:57.650 --> 00:00:57.660 align:start position:0% exponentiation operation which is quite 00:00:57.660 --> 00:00:59.869 align:start position:0% exponentiation operation which is quite expensive<00:00:57.930> on<00:00:58.260> the<00:00:58.350> EVM<00:00:58.710> and<00:00:59.039> the<00:00:59.430> same<00:00:59.609> thing 00:00:59.869 --> 00:00:59.879 align:start position:0% expensive on the EVM and the same thing 00:00:59.879 --> 00:01:01.369 align:start position:0% expensive on the EVM and the same thing can<00:01:00.120> be<00:01:00.180> achieved<00:01:00.359> with<00:01:00.780> just<00:01:01.079> a 00:01:01.369 --> 00:01:01.379 align:start position:0% can be achieved with just a 00:01:01.379 --> 00:01:05.179 align:start position:0% can be achieved with just a multiplication<00:01:01.829> multiplication<00:01:02.719> of<00:01:03.719> X<00:01:04.530> by 00:01:05.179 --> 00:01:05.189 align:start position:0% multiplication multiplication of X by 00:01:05.189 --> 00:01:08.539 align:start position:0% multiplication multiplication of X by itself<00:01:05.220> and<00:01:05.930> so<00:01:06.930> such<00:01:07.560> a<00:01:07.680> transformation<00:01:08.369> on 00:01:08.539 --> 00:01:08.549 align:start position:0% itself and so such a transformation on 00:01:08.549 --> 00:01:12.730 align:start position:0% itself and so such a transformation on solidity<00:01:09.299> would<00:01:09.990> be<00:01:10.200> a<00:01:10.970> valid<00:01:11.970> optimization 00:01:12.730 --> 00:01:12.740 align:start position:0% solidity would be a valid optimization 00:01:12.740 --> 00:01:15.859 align:start position:0% solidity would be a valid optimization optimizer<00:01:14.330> transformation<00:01:15.330> because<00:01:15.570> it<00:01:15.720> does 00:01:15.859 --> 00:01:15.869 align:start position:0% optimizer transformation because it does 00:01:15.869 --> 00:01:19.070 align:start position:0% optimizer transformation because it does the<00:01:15.990> same<00:01:16.170> thing<00:01:16.380> and<00:01:16.650> it's<00:01:17.280> cheaper<00:01:17.869> okay<00:01:18.869> but 00:01:19.070 --> 00:01:19.080 align:start position:0% the same thing and it's cheaper okay but 00:01:19.080 --> 00:01:21.230 align:start position:0% the same thing and it's cheaper okay but we<00:01:19.680> don't<00:01:19.710> want<00:01:19.979> to<00:01:20.040> optimize<00:01:20.759> solidity 00:01:21.230 --> 00:01:21.240 align:start position:0% we don't want to optimize solidity 00:01:21.240 --> 00:01:23.450 align:start position:0% we don't want to optimize solidity directly<00:01:21.840> we<00:01:22.229> want<00:01:22.439> to<00:01:22.560> optimize<00:01:23.009> the 00:01:23.450 --> 00:01:23.460 align:start position:0% directly we want to optimize the 00:01:23.460 --> 00:01:27.100 align:start position:0% directly we want to optimize the low-level<00:01:24.500> language<00:01:25.500> that<00:01:25.830> we'll<00:01:26.009> see<00:01:26.220> later 00:01:27.100 --> 00:01:27.110 align:start position:0% low-level language that we'll see later 00:01:27.110 --> 00:01:30.499 align:start position:0% low-level language that we'll see later this<00:01:28.110> thing<00:01:28.409> has<00:01:29.100> two<00:01:29.460> problems<00:01:29.970> the<00:01:30.060> first 00:01:30.499 --> 00:01:30.509 align:start position:0% this thing has two problems the first 00:01:30.509 --> 00:01:33.230 align:start position:0% this thing has two problems the first one<00:01:30.840> touches<00:01:31.710> on<00:01:31.829> the<00:01:31.920> resources<00:01:32.280> part<00:01:32.850> so 00:01:33.230 --> 00:01:33.240 align:start position:0% one touches on the resources part so 00:01:33.240 --> 00:01:35.929 align:start position:0% one touches on the resources part so what<00:01:34.200> are<00:01:34.409> actually<00:01:34.950> the<00:01:35.189> resources<00:01:35.670> we<00:01:35.790> want 00:01:35.929 --> 00:01:35.939 align:start position:0% what are actually the resources we want 00:01:35.939 --> 00:01:39.020 align:start position:0% what are actually the resources we want to<00:01:36.030> optimize<00:01:36.270> on<00:01:37.200> the<00:01:37.950> EVM<00:01:38.310> this<00:01:38.610> might<00:01:38.850> be 00:01:39.020 --> 00:01:39.030 align:start position:0% to optimize on the EVM this might be 00:01:39.030 --> 00:01:40.249 align:start position:0% to optimize on the EVM this might be trivial<00:01:39.450> of<00:01:39.570> course<00:01:39.810> we<00:01:39.900> want<00:01:40.020> to<00:01:40.079> optimize 00:01:40.249 --> 00:01:40.259 align:start position:0% trivial of course we want to optimize 00:01:40.259 --> 00:01:42.889 align:start position:0% trivial of course we want to optimize for<00:01:40.409> gas<00:01:40.740> but<00:01:41.640> if<00:01:41.939> you<00:01:42.119> take<00:01:42.420> a<00:01:42.450> closer<00:01:42.750> look 00:01:42.889 --> 00:01:42.899 align:start position:0% for gas but if you take a closer look 00:01:42.899 --> 00:01:46.630 align:start position:0% for gas but if you take a closer look then<00:01:43.290> you<00:01:43.320> see<00:01:43.710> that<00:01:44.030> yeah<00:01:45.060> gas<00:01:45.450> is<00:01:45.689> not 00:01:46.630 --> 00:01:46.640 align:start position:0% then you see that yeah gas is not 00:01:46.640 --> 00:01:49.670 align:start position:0% then you see that yeah gas is not yeahthere's<00:01:47.640> knows<00:01:48.060> not<00:01:48.689> a<00:01:48.750> unique<00:01:49.140> thing<00:01:49.500> you 00:01:49.670 --> 00:01:49.680 align:start position:0% yeahthere's knows not a unique thing you 00:01:49.680 --> 00:01:52.399 align:start position:0% yeahthere's knows not a unique thing you can<00:01:49.829> call<00:01:50.070> a<00:01:50.130> gas<00:01:50.369> or<00:01:50.909> gas<00:01:51.509> usage<00:01:51.960> of<00:01:52.110> a<00:01:52.170> smart 00:01:52.399 --> 00:01:52.409 align:start position:0% can call a gas or gas usage of a smart 00:01:52.409 --> 00:01:53.690 align:start position:0% can call a gas or gas usage of a smart contract<00:01:52.770> because<00:01:53.009> there<00:01:53.130> are<00:01:53.189> at<00:01:53.280> least<00:01:53.310> two 00:01:53.690 --> 00:01:53.700 align:start position:0% contract because there are at least two 00:01:53.700 --> 00:01:56.569 align:start position:0% contract because there are at least two the<00:01:54.270> first<00:01:54.450> is<00:01:54.780> the<00:01:55.500> gas<00:01:55.680> that<00:01:55.950> is<00:01:56.070> required<00:01:56.399> to 00:01:56.569 --> 00:01:56.579 align:start position:0% the first is the gas that is required to 00:01:56.579 --> 00:01:58.459 align:start position:0% the first is the gas that is required to deploy<00:01:56.820> the<00:01:57.299> smart<00:01:57.509> contract<00:01:57.960> and<00:01:58.170> the<00:01:58.229> second 00:01:58.459 --> 00:01:58.469 align:start position:0% deploy the smart contract and the second 00:01:58.469 --> 00:02:00.109 align:start position:0% deploy the smart contract and the second thing<00:01:58.619> is<00:01:58.799> the<00:01:58.979> gas<00:01:59.130> that<00:01:59.369> is<00:01:59.490> required<00:01:59.820> later 00:02:00.109 --> 00:02:00.119 align:start position:0% thing is the gas that is required later 00:02:00.119 --> 00:02:02.380 align:start position:0% thing is the gas that is required later if<00:02:00.479> you<00:02:00.600> call<00:02:00.869> individual<00:02:01.590> functions<00:02:01.979> and 00:02:02.380 --> 00:02:02.390 align:start position:0% if you call individual functions and 00:02:02.390 --> 00:02:06.980 align:start position:0% if you call individual functions and this<00:02:03.390> is<00:02:03.509> a<00:02:03.659> yeah<00:02:04.259> this<00:02:05.189> is<00:02:05.340> a<00:02:05.689> trade<00:02:06.689> if<00:02:06.840> that 00:02:06.980 --> 00:02:06.990 align:start position:0% this is a yeah this is a trade if that 00:02:06.990 --> 00:02:08.540 align:start position:0% this is a yeah this is a trade if that actually<00:02:07.140> matters<00:02:07.619> later<00:02:07.829> because<00:02:08.310> some 00:02:08.540 --> 00:02:08.550 align:start position:0% actually matters later because some 00:02:08.550 --> 00:02:12.530 align:start position:0% actually matters later because some routines<00:02:08.970> if<00:02:09.420> you<00:02:11.120> transform<00:02:12.120> them<00:02:12.360> to 00:02:12.530 --> 00:02:12.540 align:start position:0% routines if you transform them to 00:02:12.540 --> 00:02:13.640 align:start position:0% routines if you transform them to something<00:02:12.780> that<00:02:12.930> is<00:02:13.200> more 00:02:13.640 --> 00:02:13.650 align:start position:0% something that is more 00:02:13.650 --> 00:02:16.300 align:start position:0% something that is more compact<00:02:13.950> but<00:02:14.159> does<00:02:14.280> the<00:02:14.400> same<00:02:14.579> thing<00:02:14.819> then 00:02:16.300 --> 00:02:16.310 align:start position:0% compact but does the same thing then 00:02:16.310 --> 00:02:18.979 align:start position:0% compact but does the same thing then this<00:02:17.310> reduces<00:02:17.640> deploy<00:02:18.090> time<00:02:18.329> cost<00:02:18.599> but<00:02:18.810> most 00:02:18.979 --> 00:02:18.989 align:start position:0% this reduces deploy time cost but most 00:02:18.989 --> 00:02:21.410 align:start position:0% this reduces deploy time cost but most of<00:02:19.079> the<00:02:19.140> time<00:02:19.349> it<00:02:19.620> increases<00:02:20.129> runtime<00:02:21.090> costs 00:02:21.410 --> 00:02:21.420 align:start position:0% of the time it increases runtime costs 00:02:21.420 --> 00:02:25.640 align:start position:0% of the time it increases runtime costs so<00:02:21.989> and<00:02:22.909> the<00:02:23.909> current<00:02:24.390> optimizer<00:02:24.870> also<00:02:25.439> has<00:02:25.620> a 00:02:25.640 --> 00:02:25.650 align:start position:0% so and the current optimizer also has a 00:02:25.650 --> 00:02:28.460 align:start position:0% so and the current optimizer also has a flag<00:02:26.430> where<00:02:27.000> you<00:02:27.090> can<00:02:27.329> set<00:02:27.930> exactly<00:02:28.260> this 00:02:28.460 --> 00:02:28.470 align:start position:0% flag where you can set exactly this 00:02:28.470 --> 00:02:30.589 align:start position:0% flag where you can set exactly this trade-off<00:02:28.829> it's<00:02:29.159> called<00:02:29.400> the<00:02:29.549> runs<00:02:29.790> parameter 00:02:30.589 --> 00:02:30.599 align:start position:0% trade-off it's called the runs parameter 00:02:30.599 --> 00:02:33.170 align:start position:0% trade-off it's called the runs parameter this<00:02:31.319> is<00:02:31.379> often<00:02:31.709> misinterpreted<00:02:32.220> as<00:02:32.760> just<00:02:33.090> the 00:02:33.170 --> 00:02:33.180 align:start position:0% this is often misinterpreted as just the 00:02:33.180 --> 00:02:35.750 align:start position:0% this is often misinterpreted as just the number<00:02:33.450> of<00:02:33.480> runs<00:02:33.780> you<00:02:34.200> want<00:02:34.409> to<00:02:34.700> amount<00:02:35.700> of 00:02:35.750 --> 00:02:35.760 align:start position:0% number of runs you want to amount of 00:02:35.760 --> 00:02:36.890 align:start position:0% number of runs you want to amount of effort<00:02:35.939> you<00:02:36.090> want<00:02:36.269> to<00:02:36.329> put<00:02:36.540> into<00:02:36.750> the 00:02:36.890 --> 00:02:36.900 align:start position:0% effort you want to put into the 00:02:36.900 --> 00:02:38.990 align:start position:0% effort you want to put into the optimizer<00:02:37.319> but<00:02:37.859> it's<00:02:37.950> actually<00:02:38.159> exactly<00:02:38.609> this 00:02:38.990 --> 00:02:39.000 align:start position:0% optimizer but it's actually exactly this 00:02:39.000 --> 00:02:41.449 align:start position:0% optimizer but it's actually exactly this trade-off<00:02:39.329> and<00:02:39.659> this<00:02:40.620> trade-off<00:02:40.890> problem 00:02:41.449 --> 00:02:41.459 align:start position:0% trade-off and this trade-off problem 00:02:41.459 --> 00:02:43.339 align:start position:0% trade-off and this trade-off problem gets<00:02:42.060> even<00:02:42.269> more<00:02:42.299> complicated<00:02:42.780> when<00:02:43.230> you<00:02:43.319> have 00:02:43.339 --> 00:02:43.349 align:start position:0% gets even more complicated when you have 00:02:43.349 --> 00:02:47.809 align:start position:0% gets even more complicated when you have loops<00:02:43.799> because<00:02:44.340> then<00:02:44.640> you<00:02:44.939> might<00:02:45.150> want<00:02:45.450> to<00:02:46.819> you 00:02:47.809 --> 00:02:47.819 align:start position:0% loops because then you might want to you 00:02:47.819 --> 00:02:50.539 align:start position:0% loops because then you might want to you so<00:02:48.290> for<00:02:49.290> the<00:02:49.470> code<00:02:49.680> that<00:02:49.829> is<00:02:49.950> inside<00:02:50.190> the<00:02:50.250> loop 00:02:50.539 --> 00:02:50.549 align:start position:0% so for the code that is inside the loop 00:02:50.549 --> 00:02:52.369 align:start position:0% so for the code that is inside the loop that<00:02:50.670> is<00:02:50.730> executed<00:02:51.269> executed<00:02:51.900> more<00:02:52.079> often 00:02:52.369 --> 00:02:52.379 align:start position:0% that is executed executed more often 00:02:52.379 --> 00:02:54.129 align:start position:0% that is executed executed more often than<00:02:52.530> the<00:02:52.620> code<00:02:52.799> outside<00:02:52.980> of<00:02:53.310> the<00:02:53.400> loop<00:02:53.549> so 00:02:54.129 --> 00:02:54.139 align:start position:0% than the code outside of the loop so 00:02:54.139 --> 00:02:56.390 align:start position:0% than the code outside of the loop so there<00:02:55.139> it's<00:02:55.379> even<00:02:55.590> more<00:02:55.739> important<00:02:56.220> that<00:02:56.250> the 00:02:56.390 --> 00:02:56.400 align:start position:0% there it's even more important that the 00:02:56.400 --> 00:02:59.599 align:start position:0% there it's even more important that the runtime<00:02:56.790> costs<00:02:57.209> are<00:02:57.299> lower<00:02:57.480> and<00:02:57.750> you<00:02:57.900> might<00:02:58.609> be 00:02:59.599 --> 00:02:59.609 align:start position:0% runtime costs are lower and you might be 00:02:59.609 --> 00:03:02.119 align:start position:0% runtime costs are lower and you might be fine<00:02:59.849> with<00:03:00.030> a<00:03:00.060> little<00:03:00.150> bit<00:03:00.450> more<00:03:00.889> deploy<00:03:01.889> time 00:03:02.119 --> 00:03:02.129 align:start position:0% fine with a little bit more deploy time 00:03:02.129 --> 00:03:04.339 align:start position:0% fine with a little bit more deploy time costs<00:03:02.489> in<00:03:02.639> such<00:03:02.790> cases<00:03:03.000> but<00:03:03.269> yeah<00:03:03.959> these<00:03:04.139> are 00:03:04.339 --> 00:03:04.349 align:start position:0% costs in such cases but yeah these are 00:03:04.349 --> 00:03:06.319 align:start position:0% costs in such cases but yeah these are tough<00:03:04.829> decisions<00:03:04.889> for<00:03:05.430> the<00:03:05.549> optimizer<00:03:05.939> and<00:03:06.090> it 00:03:06.319 --> 00:03:06.329 align:start position:0% tough decisions for the optimizer and it 00:03:06.329 --> 00:03:09.199 align:start position:0% tough decisions for the optimizer and it will<00:03:06.629> not<00:03:06.810> always<00:03:06.930> get<00:03:07.200> it<00:03:07.319> right<00:03:07.500> and<00:03:08.209> the 00:03:09.199 --> 00:03:09.209 align:start position:0% will not always get it right and the 00:03:09.209 --> 00:03:11.509 align:start position:0% will not always get it right and the second<00:03:09.540> problem<00:03:09.689> is<00:03:10.049> that<00:03:10.680> even<00:03:10.920> if<00:03:11.159> you<00:03:11.340> have 00:03:11.509 --> 00:03:11.519 align:start position:0% second problem is that even if you have 00:03:11.519 --> 00:03:13.399 align:start position:0% second problem is that even if you have a<00:03:11.549> clearly<00:03:12.180> defined<00:03:12.540> mathematically<00:03:13.139> defined 00:03:13.399 --> 00:03:13.409 align:start position:0% a clearly defined mathematically defined 00:03:13.409 --> 00:03:16.369 align:start position:0% a clearly defined mathematically defined metric<00:03:13.799> for<00:03:14.099> resource<00:03:14.760> consumption<00:03:15.319> it<00:03:16.319> is 00:03:16.369 --> 00:03:16.379 align:start position:0% metric for resource consumption it is 00:03:16.379 --> 00:03:18.619 align:start position:0% metric for resource consumption it is theoretically<00:03:17.069> impossible<00:03:17.400> to<00:03:18.150> create<00:03:18.449> a 00:03:18.619 --> 00:03:18.629 align:start position:0% theoretically impossible to create a 00:03:18.629 --> 00:03:21.110 align:start position:0% theoretically impossible to create a perfect<00:03:19.290> optimizer<00:03:19.739> and<00:03:19.919> perfect<00:03:20.790> optimizer 00:03:21.110 --> 00:03:21.120 align:start position:0% perfect optimizer and perfect optimizer 00:03:21.120 --> 00:03:23.890 align:start position:0% perfect optimizer and perfect optimizer means<00:03:21.389> it<00:03:22.379> takes<00:03:22.590> a<00:03:22.769> program<00:03:23.069> is<00:03:23.160> input<00:03:23.519> and 00:03:23.890 --> 00:03:23.900 align:start position:0% means it takes a program is input and 00:03:23.900 --> 00:03:26.689 align:start position:0% means it takes a program is input and the<00:03:24.900> output<00:03:24.930> program<00:03:25.590> is<00:03:25.799> the<00:03:26.040> best<00:03:26.160> possible 00:03:26.689 --> 00:03:26.699 align:start position:0% the output program is the best possible 00:03:26.699 --> 00:03:28.490 align:start position:0% the output program is the best possible program<00:03:27.000> that<00:03:27.120> does<00:03:27.239> the<00:03:27.359> same<00:03:27.389> thing<00:03:27.780> with 00:03:28.490 --> 00:03:28.500 align:start position:0% program that does the same thing with 00:03:28.500 --> 00:03:30.800 align:start position:0% program that does the same thing with the<00:03:28.829> least<00:03:29.340> amount<00:03:29.579> of<00:03:29.819> resource<00:03:30.150> usage<00:03:30.599> and 00:03:30.800 --> 00:03:30.810 align:start position:0% the least amount of resource usage and 00:03:30.810 --> 00:03:36.680 align:start position:0% the least amount of resource usage and the<00:03:31.139> reason<00:03:31.500> for<00:03:31.530> that<00:03:31.680> is<00:03:32.840> yeah<00:03:33.840> not<00:03:34.190> not<00:03:35.690> the 00:03:36.680 --> 00:03:36.690 align:start position:0% the reason for that is yeah not not the 00:03:36.690 --> 00:03:38.569 align:start position:0% the reason for that is yeah not not the problem<00:03:36.989> that<00:03:37.319> that<00:03:37.530> finding<00:03:37.859> this<00:03:38.159> optimal 00:03:38.569 --> 00:03:38.579 align:start position:0% problem that that finding this optimal 00:03:38.579 --> 00:03:41.089 align:start position:0% problem that that finding this optimal program<00:03:39.030> is<00:03:39.329> too<00:03:40.049> difficult<00:03:40.319> because<00:03:40.980> the 00:03:41.089 --> 00:03:41.099 align:start position:0% program is too difficult because the 00:03:41.099 --> 00:03:42.589 align:start position:0% program is too difficult because the search<00:03:41.310> space<00:03:41.579> is<00:03:41.609> too<00:03:41.909> large<00:03:42.090> or<00:03:42.329> something 00:03:42.589 --> 00:03:42.599 align:start position:0% search space is too large or something 00:03:42.599 --> 00:03:45.050 align:start position:0% search space is too large or something like<00:03:42.659> that<00:03:42.810> but<00:03:43.319> it's<00:03:44.040> the<00:03:44.669> semantic 00:03:45.050 --> 00:03:45.060 align:start position:0% like that but it's the semantic 00:03:45.060 --> 00:03:48.890 align:start position:0% like that but it's the semantic equivalence<00:03:45.419> and<00:03:46.519> more<00:03:47.519> specifically<00:03:48.090> you 00:03:48.890 --> 00:03:48.900 align:start position:0% equivalence and more specifically you 00:03:48.900 --> 00:03:50.930 align:start position:0% equivalence and more specifically you probably<00:03:49.709> heard<00:03:50.190> about<00:03:50.310> the<00:03:50.609> halting<00:03:50.909> problem 00:03:50.930 --> 00:03:50.940 align:start position:0% probably heard about the halting problem 00:03:50.940 --> 00:03:53.809 align:start position:0% probably heard about the halting problem that<00:03:51.389> gets<00:03:51.510> cited<00:03:51.810> all<00:03:52.560> the<00:03:52.979> way<00:03:53.099> in<00:03:53.430> Turing 00:03:53.809 --> 00:03:53.819 align:start position:0% that gets cited all the way in Turing 00:03:53.819 --> 00:03:58.640 align:start position:0% that gets cited all the way in Turing complete<00:03:54.620> for<00:03:55.620> Turing<00:03:55.859> complete<00:03:57.650> blockchain 00:03:58.640 --> 00:03:58.650 align:start position:0% complete for Turing complete blockchain 00:03:58.650 --> 00:04:01.610 align:start position:0% complete for Turing complete blockchain smart<00:03:59.129> contract<00:04:00.109> execution<00:04:01.109> environments 00:04:01.610 --> 00:04:01.620 align:start position:0% smart contract execution environments 00:04:01.620 --> 00:04:06.649 align:start position:0% smart contract execution environments and<00:04:03.709> you<00:04:04.709> can<00:04:04.859> show<00:04:05.099> via<00:04:05.909> the<00:04:06.120> halting<00:04:06.419> problem 00:04:06.649 --> 00:04:06.659 align:start position:0% and you can show via the halting problem 00:04:06.659 --> 00:04:09.770 align:start position:0% and you can show via the halting problem that<00:04:07.049> a<00:04:07.579> perfect<00:04:08.579> optimizer<00:04:08.940> is<00:04:09.209> impossible 00:04:09.770 --> 00:04:09.780 align:start position:0% that a perfect optimizer is impossible 00:04:09.780 --> 00:04:13.099 align:start position:0% that a perfect optimizer is impossible and<00:04:10.760> yeah<00:04:11.760> the<00:04:11.879> halting<00:04:12.180> problem<00:04:12.209> is<00:04:12.690> that 00:04:13.099 --> 00:04:13.109 align:start position:0% and yeah the halting problem is that 00:04:13.109 --> 00:04:15.649 align:start position:0% and yeah the halting problem is that it's<00:04:13.829> a<00:04:14.010> result<00:04:14.790> from<00:04:14.940> theoretical<00:04:15.389> computer 00:04:15.649 --> 00:04:15.659 align:start position:0% it's a result from theoretical computer 00:04:15.659 --> 00:04:16.909 align:start position:0% it's a result from theoretical computer science<00:04:15.900> and<00:04:16.019> it<00:04:16.079> says<00:04:16.229> that<00:04:16.470> there<00:04:16.709> is<00:04:16.799> no 00:04:16.909 --> 00:04:16.919 align:start position:0% science and it says that there is no 00:04:16.919 --> 00:04:20.000 align:start position:0% science and it says that there is no program<00:04:17.159> that<00:04:17.669> decides<00:04:18.630> on<00:04:18.810> a<00:04:18.900> given<00:04:19.199> input 00:04:20.000 --> 00:04:20.010 align:start position:0% program that decides on a given input 00:04:20.010 --> 00:04:21.709 align:start position:0% program that decides on a given input program<00:04:20.549> whether<00:04:20.699> it<00:04:21.000> halts<00:04:21.419> on<00:04:21.510> all<00:04:21.570> inputs 00:04:21.709 --> 00:04:21.719 align:start position:0% program whether it halts on all inputs 00:04:21.719 --> 00:04:23.409 align:start position:0% program whether it halts on all inputs or<00:04:22.320> not 00:04:23.409 --> 00:04:23.419 align:start position:0% or not 00:04:23.419 --> 00:04:26.260 align:start position:0% or not and<00:04:23.710> because<00:04:24.710> we're<00:04:24.949> in<00:04:24.979> on<00:04:25.370> the<00:04:25.490> EVM<00:04:25.789> here<00:04:26.090> we 00:04:26.260 --> 00:04:26.270 align:start position:0% and because we're in on the EVM here we 00:04:26.270 --> 00:04:29.020 align:start position:0% and because we're in on the EVM here we replace<00:04:26.659> halt<00:04:27.110> by<00:04:27.319> revert<00:04:27.650> and<00:04:27.949> this<00:04:28.759> is<00:04:28.879> still 00:04:29.020 --> 00:04:29.030 align:start position:0% replace halt by revert and this is still 00:04:29.030 --> 00:04:34.899 align:start position:0% replace halt by revert and this is still true<00:04:29.150> and<00:04:30.999> so<00:04:32.710> we<00:04:33.710> now<00:04:33.830> assume<00:04:34.249> that<00:04:34.279> we<00:04:34.669> have<00:04:34.699> a 00:04:34.899 --> 00:04:34.909 align:start position:0% true and so we now assume that we have a 00:04:34.909 --> 00:04:37.089 align:start position:0% true and so we now assume that we have a perfect<00:04:35.210> optimizer<00:04:35.810> and<00:04:36.139> use<00:04:36.379> that<00:04:36.680> perfect 00:04:37.089 --> 00:04:37.099 align:start position:0% perfect optimizer and use that perfect 00:04:37.099 --> 00:04:38.679 align:start position:0% perfect optimizer and use that perfect optimizer<00:04:37.490> to<00:04:37.999> solve<00:04:38.240> the<00:04:38.389> halting<00:04:38.479> problem 00:04:38.679 --> 00:04:38.689 align:start position:0% optimizer to solve the halting problem 00:04:38.689 --> 00:04:41.080 align:start position:0% optimizer to solve the halting problem and<00:04:39.199> because<00:04:39.650> of<00:04:39.680> that<00:04:39.889> perfect<00:04:40.340> optimizer<00:04:40.789> is 00:04:41.080 --> 00:04:41.090 align:start position:0% and because of that perfect optimizer is 00:04:41.090 --> 00:04:45.149 align:start position:0% and because of that perfect optimizer is impossible<00:04:41.689> and<00:04:43.060> yeah<00:04:44.060> the<00:04:44.240> way<00:04:44.389> we<00:04:44.539> do<00:04:44.689> it<00:04:44.840> is 00:04:45.149 --> 00:04:45.159 align:start position:0% impossible and yeah the way we do it is 00:04:45.159 --> 00:04:49.629 align:start position:0% impossible and yeah the way we do it is so<00:04:46.689> if<00:04:47.689> a<00:04:48.020> program<00:04:48.229> reverts<00:04:48.979> on<00:04:49.219> all<00:04:49.430> inputs 00:04:49.629 --> 00:04:49.639 align:start position:0% so if a program reverts on all inputs 00:04:49.639 --> 00:04:53.769 align:start position:0% so if a program reverts on all inputs and<00:04:50.120> it's<00:04:50.840> the<00:04:51.110> shortest<00:04:51.919> program<00:04:52.669> then<00:04:53.360> it 00:04:53.769 --> 00:04:53.779 align:start position:0% and it's the shortest program then it 00:04:53.779 --> 00:04:55.450 align:start position:0% and it's the shortest program then it has<00:04:53.990> to<00:04:54.229> look<00:04:54.379> something<00:04:54.740> like<00:04:54.800> this<00:04:55.159> empty 00:04:55.450 --> 00:04:55.460 align:start position:0% has to look something like this empty 00:04:55.460 --> 00:04:58.179 align:start position:0% has to look something like this empty contract<00:04:55.849> here<00:04:56.620> because<00:04:57.620> that's<00:04:57.740> the<00:04:57.949> shorter 00:04:58.179 --> 00:04:58.189 align:start position:0% contract here because that's the shorter 00:04:58.189 --> 00:04:59.980 align:start position:0% contract here because that's the shorter program<00:04:58.909> that<00:04:59.029> revolts<00:04:59.330> on<00:04:59.419> all<00:04:59.509> inputs<00:04:59.659> and 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position:0% input and if it outputs this empty smart 00:05:07.879 --> 00:05:10.269 align:start position:0% input and if it outputs this empty smart contract<00:05:08.300> then<00:05:08.590> the<00:05:09.590> input<00:05:09.740> halts<00:05:10.129> on<00:05:10.189> all 00:05:10.269 --> 00:05:10.279 align:start position:0% contract then the input halts on all 00:05:10.279 --> 00:05:12.999 align:start position:0% contract then the input halts on all inputs<00:05:10.340> and<00:05:10.759> otherwise<00:05:10.969> not<00:05:11.710> okay<00:05:12.710> that's<00:05:12.860> a 00:05:12.999 --> 00:05:13.009 align:start position:0% inputs and otherwise not okay that's a 00:05:13.009 --> 00:05:15.429 align:start position:0% inputs and otherwise not okay that's a nice<00:05:13.159> theoretical<00:05:13.729> result<00:05:14.000> but<00:05:14.439> yeah 00:05:15.429 --> 00:05:15.439 align:start position:0% nice theoretical result but yeah 00:05:15.439 --> 00:05:17.529 align:start position:0% nice theoretical result but yeah completely<00:05:16.099> useless<00:05:16.250> for<00:05:16.460> practice<00:05:17.330> I<00:05:17.479> mean 00:05:17.529 --> 00:05:17.539 align:start position:0% completely useless for practice I mean 00:05:17.539 --> 00:05:21.999 align:start position:0% completely useless for practice I mean it's<00:05:18.110> nice<00:05:18.289> to<00:05:18.620> know<00:05:19.300> the<00:05:20.300> lower<00:05:21.259> bounds<00:05:21.800> and 00:05:21.999 --> 00:05:22.009 align:start position:0% it's nice to know the lower bounds and 00:05:22.009 --> 00:05:24.989 align:start position:0% it's nice to know the lower bounds and where<00:05:22.370> we<00:05:22.490> cannot<00:05:22.759> go<00:05:23.029> but<00:05:23.689> if<00:05:23.810> we<00:05:23.900> relax<00:05:24.169> this 00:05:24.989 --> 00:05:24.999 align:start position:0% where we cannot go but if we relax this 00:05:24.999 --> 00:05:29.939 align:start position:0% where we cannot go but if we relax this optimal<00:05:25.999> thing<00:05:26.270> we<00:05:26.539> can<00:05:26.779> get<00:05:26.979> quite<00:05:27.979> far<00:05:28.250> so 00:05:29.939 --> 00:05:29.949 align:start position:0% optimal thing we can get quite far so 00:05:29.949 --> 00:05:32.559 align:start position:0% optimal thing we can get quite far so now<00:05:30.949> next<00:05:31.159> question<00:05:31.550> you<00:05:31.580> might<00:05:31.669> ask<00:05:31.819> is<00:05:32.240> why 00:05:32.559 --> 00:05:32.569 align:start position:0% now next question you might ask is why 00:05:32.569 --> 00:05:34.570 align:start position:0% now next question you might ask is why do<00:05:32.629> we<00:05:32.930> want<00:05:33.110> an<00:05:33.229> optimizer<00:05:33.650> and<00:05:33.860> there<00:05:34.069> is 00:05:34.570 --> 00:05:34.580 align:start position:0% do we want an optimizer and there is 00:05:34.580 --> 00:05:37.300 align:start position:0% do we want an optimizer and there is probably<00:05:35.360> an<00:05:35.689> obvious<00:05:36.080> answer<00:05:36.289> and<00:05:37.099> that<00:05:37.279> is 00:05:37.300 --> 00:05:37.310 align:start position:0% probably an obvious answer and that is 00:05:37.310 --> 00:05:39.670 align:start position:0% probably an obvious answer and that is we<00:05:37.580> want<00:05:37.610> cheaper<00:05:38.150> smart<00:05:38.389> contracts<00:05:38.810> but<00:05:39.439> if 00:05:39.670 --> 00:05:39.680 align:start position:0% we want cheaper smart contracts but if 00:05:39.680 --> 00:05:42.820 align:start position:0% we want cheaper smart contracts but if you<00:05:39.800> take<00:05:40.159> a<00:05:40.189> closer<00:05:40.490> look<00:05:40.639> then<00:05:40.939> this<00:05:41.180> is<00:05:41.830> not 00:05:42.820 --> 00:05:42.830 align:start position:0% you take a closer look then this is not 00:05:42.830 --> 00:05:45.269 align:start position:0% you take a closer look then this is not the<00:05:43.069> main<00:05:43.279> reason<00:05:43.310> to<00:05:43.819> have<00:05:43.939> an<00:05:44.089> optimizer 00:05:45.269 --> 00:05:45.279 align:start position:0% the main reason to have an optimizer 00:05:45.279 --> 00:05:49.420 align:start position:0% the main reason to have an optimizer instead<00:05:46.539> an<00:05:47.539> optimizer<00:05:48.020> allows<00:05:48.319> you<00:05:48.589> to<00:05:48.800> write 00:05:49.420 --> 00:05:49.430 align:start position:0% instead an optimizer allows you to write 00:05:49.430 --> 00:05:51.429 align:start position:0% instead an optimizer allows you to write your<00:05:49.699> code<00:05:49.969> in<00:05:50.210> a<00:05:50.300> more<00:05:50.509> modular<00:05:50.960> and<00:05:51.169> more 00:05:51.429 --> 00:05:51.439 align:start position:0% your code in a more modular and more 00:05:51.439 --> 00:05:55.540 align:start position:0% your code in a more modular and more understandable<00:05:52.159> way<00:05:52.310> so<00:05:53.139> if<00:05:54.139> you<00:05:54.830> do<00:05:55.159> not<00:05:55.310> use 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oh is this is this cheap 00:06:02.839 --> 00:06:04.899 align:start position:0% to consider oh is this is this cheap enough<00:06:03.050> what<00:06:03.259> I'm<00:06:03.349> writing<00:06:03.500> here<00:06:03.830> or<00:06:03.979> not<00:06:04.159> can 00:06:04.899 --> 00:06:04.909 align:start position:0% enough what I'm writing here or not can 00:06:04.909 --> 00:06:07.689 align:start position:0% enough what I'm writing here or not can I<00:06:05.000> change<00:06:05.330> it<00:06:05.569> in<00:06:05.930> a<00:06:06.349> way<00:06:06.379> so<00:06:06.620> that<00:06:06.919> it's<00:06:07.219> it's<00:06:07.610> a 00:06:07.689 --> 00:06:07.699 align:start position:0% I change it in a way so that it's it's a 00:06:07.699 --> 00:06:09.399 align:start position:0% I change it in a way so that it's it's a little<00:06:07.909> bit<00:06:08.029> cheaper<00:06:08.210> and<00:06:08.539> still<00:06:09.169> that's<00:06:09.289> the 00:06:09.399 --> 00:06:09.409 align:start position:0% little bit cheaper and still that's the 00:06:09.409 --> 00:06:11.920 align:start position:0% little bit cheaper and still that's the same<00:06:09.589> thing<00:06:09.800> and<00:06:10.180> but<00:06:11.180> if<00:06:11.300> you<00:06:11.389> know<00:06:11.539> that<00:06:11.779> the 00:06:11.920 --> 00:06:11.930 align:start position:0% same thing and but if you know that the 00:06:11.930 --> 00:06:13.540 align:start position:0% same thing and but if you know that the optimizer<00:06:12.319> will<00:06:12.500> just<00:06:12.649> do<00:06:12.770> that<00:06:12.889> for<00:06:13.129> yourself 00:06:13.540 --> 00:06:13.550 align:start position:0% optimizer will just do that for yourself 00:06:13.550 --> 00:06:16.240 align:start position:0% optimizer will just do that for yourself then<00:06:14.240> you<00:06:15.080> can<00:06:15.289> write<00:06:15.710> it<00:06:15.740> so<00:06:16.009> that<00:06:16.039> it's 00:06:16.240 --> 00:06:16.250 align:start position:0% then you can write it so that it's 00:06:16.250 --> 00:06:19.990 align:start position:0% then you can write it so that it's readable<00:06:16.669> it's<00:06:17.149> auditable<00:06:17.779> you<00:06:18.379> are<00:06:19.000> 100% 00:06:19.990 --> 00:06:20.000 align:start position:0% readable it's auditable you are 100% 00:06:20.000 --> 00:06:22.300 align:start position:0% readable it's auditable you are 100% sure<00:06:20.089> that<00:06:20.120> it<00:06:20.389> works<00:06:20.629> and<00:06:20.930> you<00:06:21.710> don't<00:06:22.009> have<00:06:22.159> to 00:06:22.300 --> 00:06:22.310 align:start position:0% sure that it works and you don't have to 00:06:22.310 --> 00:06:23.619 align:start position:0% sure that it works and you don't have to care<00:06:22.520> about<00:06:22.669> the<00:06:22.939> resource<00:06:23.149> consumption<00:06:23.449> all 00:06:23.619 --> 00:06:23.629 align:start position:0% care about the resource consumption all 00:06:23.629 --> 00:06:25.990 align:start position:0% care about the resource consumption all the<00:06:23.719> time<00:06:23.899> and<00:06:24.169> an<00:06:24.800> example<00:06:25.069> of<00:06:25.250> that<00:06:25.310> is<00:06:25.639> this 00:06:25.990 --> 00:06:26.000 align:start position:0% the time and an example of that is this 00:06:26.000 --> 00:06:30.659 align:start position:0% the time and an example of that is this smart<00:06:26.270> contract<00:06:26.750> here<00:06:28.899> it's<00:06:29.899> a<00:06:30.139> simple 00:06:30.659 --> 00:06:30.669 align:start position:0% smart contract here it's a simple 00:06:30.669 --> 00:06:32.980 align:start position:0% smart contract here it's a simple fragment<00:06:31.669> of<00:06:31.729> a<00:06:31.819> voting<00:06:32.000> contract<00:06:32.569> we<00:06:32.810> have<00:06:32.959> a 00:06:32.980 --> 00:06:32.990 align:start position:0% fragment of a voting contract we have a 00:06:32.990 --> 00:06:35.670 align:start position:0% fragment of a voting contract we have a vote<00:06:33.440> function<00:06:34.009> which<00:06:34.279> takes<00:06:34.519> an<00:06:34.699> output 00:06:35.670 --> 00:06:35.680 align:start position:0% vote function which takes an output 00:06:35.680 --> 00:06:38.670 align:start position:0% vote function which takes an output and<00:06:35.770> an<00:06:35.979> outcome<00:06:36.190> we<00:06:36.610> want<00:06:36.669> to<00:06:36.880> vote<00:06:37.030> and<00:06:37.680> it 00:06:38.670 --> 00:06:38.680 align:start position:0% and an outcome we want to vote and it 00:06:38.680 --> 00:06:40.999 align:start position:0% and an outcome we want to vote and it checks<00:06:38.919> that<00:06:39.190> the<00:06:39.400> user<00:06:39.580> has<00:06:39.850> not<00:06:39.880> voted<00:06:40.150> yet 00:06:40.999 --> 00:06:41.009 align:start position:0% checks that the user has not voted yet 00:06:41.009 --> 00:06:44.850 align:start position:0% checks that the user has not voted yet and<00:06:42.009> it<00:06:42.970> if<00:06:43.479> the<00:06:43.690> user<00:06:43.840> hasn't<00:06:44.080> voted<00:06:44.350> yet<00:06:44.560> it 00:06:44.850 --> 00:06:44.860 align:start position:0% and it if the user hasn't voted yet it 00:06:44.860 --> 00:06:47.879 align:start position:0% and it if the user hasn't voted yet it assigns<00:06:45.160> the<00:06:45.520> weight<00:06:45.910> of<00:06:46.300> the<00:06:46.690> user<00:06:46.900> to<00:06:47.080> the 00:06:47.879 --> 00:06:47.889 align:start position:0% assigns the weight of the user to the 00:06:47.889 --> 00:06:49.980 align:start position:0% assigns the weight of the user to the votes<00:06:48.130> and<00:06:48.430> you<00:06:49.120> see<00:06:49.270> that<00:06:49.360> this<00:06:49.509> weight<00:06:49.750> off 00:06:49.980 --> 00:06:49.990 align:start position:0% votes and you see that this weight off 00:06:49.990 --> 00:06:51.659 align:start position:0% votes and you see that this weight off is<00:06:50.229> another<00:06:50.470> function<00:06:50.710> that<00:06:51.070> just<00:06:51.310> returns 00:06:51.659 --> 00:06:51.669 align:start position:0% is another function that just returns 00:06:51.669 --> 00:06:53.850 align:start position:0% is another function that just returns ten<00:06:52.150> for<00:06:52.330> the<00:06:52.389> owner<00:06:52.539> and<00:06:52.990> one<00:06:53.410> for<00:06:53.590> everyone 00:06:53.850 --> 00:06:53.860 align:start position:0% ten for the owner and one for everyone 00:06:53.860 --> 00:06:59.400 align:start position:0% ten for the owner and one for everyone else<00:06:54.039> and<00:06:56.759> without<00:06:57.759> an<00:06:58.060> optimizer<00:06:58.449> this<00:06:59.169> would 00:06:59.400 --> 00:06:59.410 align:start position:0% else and without an optimizer this would 00:06:59.410 --> 00:07:01.890 align:start position:0% else and without an optimizer this would perform<00:06:59.949> a<00:07:00.039> function<00:07:00.370> call<00:07:00.550> which<00:07:00.850> is<00:07:01.030> costly 00:07:01.890 --> 00:07:01.900 align:start position:0% perform a function call which is costly 00:07:01.900 --> 00:07:05.879 align:start position:0% perform a function call which is costly so<00:07:02.380> a<00:07:03.509> cheaper<00:07:04.509> way<00:07:04.690> would<00:07:04.900> be<00:07:04.930> to<00:07:05.259> just<00:07:05.470> take 00:07:05.879 --> 00:07:05.889 align:start position:0% so a cheaper way would be to just take 00:07:05.889 --> 00:07:08.339 align:start position:0% so a cheaper way would be to just take this<00:07:06.130> this<00:07:07.000> this<00:07:07.300> statement<00:07:07.539> that<00:07:07.840> is<00:07:07.930> inside 00:07:08.339 --> 00:07:08.349 align:start position:0% this this this statement that is inside 00:07:08.349 --> 00:07:10.110 align:start position:0% this this this statement that is inside the<00:07:08.500> function<00:07:08.680> and<00:07:08.949> put<00:07:09.160> it<00:07:09.310> at<00:07:09.699> the<00:07:09.849> point<00:07:09.970> of 00:07:10.110 --> 00:07:10.120 align:start position:0% the function and put it at the point of 00:07:10.120 --> 00:07:12.839 align:start position:0% the function and put it at the point of the<00:07:10.210> function<00:07:10.360> call<00:07:10.690> but<00:07:11.530> that<00:07:11.680> will<00:07:11.919> yeah 00:07:12.839 --> 00:07:12.849 align:start position:0% the function call but that will yeah 00:07:12.849 --> 00:07:15.900 align:start position:0% the function call but that will yeah that<00:07:13.060> will<00:07:13.240> reduce<00:07:13.690> readability<00:07:14.370> it<00:07:15.370> will<00:07:15.729> not 00:07:15.900 --> 00:07:15.910 align:start position:0% that will reduce readability it will not 00:07:15.910 --> 00:07:18.360 align:start position:0% that will reduce readability it will not tell<00:07:16.120> you<00:07:16.300> what<00:07:16.509> this<00:07:16.720> weird<00:07:17.289> expression<00:07:17.889> 10:1 00:07:18.360 --> 00:07:18.370 align:start position:0% tell you what this weird expression 10:1 00:07:18.370 --> 00:07:20.820 align:start position:0% tell you what this weird expression 10:1 actually<00:07:18.759> is<00:07:18.910> now<00:07:19.169> in<00:07:20.169> the<00:07:20.500> way<00:07:20.590> it's<00:07:20.710> written 00:07:20.820 --> 00:07:20.830 align:start position:0% actually is now in the way it's written 00:07:20.830 --> 00:07:23.070 align:start position:0% actually is now in the way it's written now<00:07:20.979> we<00:07:21.099> see<00:07:21.430> yes<00:07:21.639> the<00:07:21.849> weight<00:07:22.000> of<00:07:22.270> the<00:07:22.599> vote 00:07:23.070 --> 00:07:23.080 align:start position:0% now we see yes the weight of the vote 00:07:23.080 --> 00:07:27.029 align:start position:0% now we see yes the weight of the vote and<00:07:24.150> also<00:07:25.150> if<00:07:25.270> we<00:07:25.419> use<00:07:25.570> this<00:07:25.780> weight<00:07:26.080> if<00:07:26.710> it's 00:07:27.029 --> 00:07:27.039 align:start position:0% and also if we use this weight if it's 00:07:27.039 --> 00:07:28.320 align:start position:0% and also if we use this weight if it's like<00:07:27.190> that<00:07:27.370> we<00:07:27.520> can<00:07:27.669> use<00:07:27.789> the<00:07:27.940> function<00:07:28.240> from 00:07:28.320 --> 00:07:28.330 align:start position:0% like that we can use the function from 00:07:28.330 --> 00:07:30.089 align:start position:0% like that we can use the function from other<00:07:28.509> places<00:07:28.780> and<00:07:29.169> then<00:07:29.349> modify<00:07:29.680> the<00:07:29.860> weights 00:07:30.089 --> 00:07:30.099 align:start position:0% other places and then modify the weights 00:07:30.099 --> 00:07:31.860 align:start position:0% other places and then modify the weights without<00:07:30.280> having<00:07:30.669> to<00:07:30.759> modify<00:07:31.090> it<00:07:31.150> everywhere 00:07:31.860 --> 00:07:31.870 align:start position:0% without having to modify it everywhere 00:07:31.870 --> 00:07:36.540 align:start position:0% without having to modify it everywhere in<00:07:31.990> the<00:07:32.080> code<00:07:34.050> okay<00:07:35.050> in<00:07:35.860> the<00:07:35.949> rest<00:07:36.099> of<00:07:36.190> the<00:07:36.310> talk 00:07:36.540 --> 00:07:36.550 align:start position:0% in the code okay in the rest of the talk 00:07:36.550 --> 00:07:41.189 align:start position:0% in the code okay in the rest of the talk I<00:07:37.830> will<00:07:38.830> quickly<00:07:39.370> describe<00:07:39.880> how<00:07:40.599> the<00:07:40.659> current 00:07:41.189 --> 00:07:41.199 align:start position:0% I will quickly describe how the current 00:07:41.199 --> 00:07:43.760 align:start position:0% I will quickly describe how the current solidity<00:07:41.919> optimizer<00:07:42.370> works<00:07:42.639> and<00:07:42.970> then 00:07:43.760 --> 00:07:43.770 align:start position:0% solidity optimizer works and then 00:07:43.770 --> 00:07:51.750 align:start position:0% solidity optimizer works and then explain<00:07:44.770> what<00:07:45.550> we<00:07:45.729> plan<00:07:46.000> to<00:07:46.780> do<00:07:46.990> on<00:07:47.409> you'll<00:07:50.760> the 00:07:51.750 --> 00:07:51.760 align:start position:0% explain what we plan to do on you'll the 00:07:51.760 --> 00:07:56.100 align:start position:0% explain what we plan to do on you'll the current<00:07:52.479> optimizer<00:07:53.050> is<00:07:54.000> wholly<00:07:55.000> based<00:07:55.300> on<00:07:55.630> up 00:07:56.100 --> 00:07:56.110 align:start position:0% current optimizer is wholly based on up 00:07:56.110 --> 00:07:59.600 align:start position:0% current optimizer is wholly based on up code<00:07:56.409> stream<00:07:56.710> so<00:07:56.889> it's<00:07:57.039> extremely<00:07:57.220> low-level 00:07:59.600 --> 00:07:59.610 align:start position:0% code stream so it's extremely low-level 00:07:59.610 --> 00:08:03.000 align:start position:0% code stream so it's extremely low-level yeah<00:08:00.610> it<00:08:00.699> has<00:08:00.880> several<00:08:01.150> stages<00:08:01.539> I<00:08:02.229> won't<00:08:02.860> go 00:08:03.000 --> 00:08:03.010 align:start position:0% yeah it has several stages I won't go 00:08:03.010 --> 00:08:05.879 align:start position:0% yeah it has several stages I won't go into<00:08:03.159> detail<00:08:03.580> for<00:08:03.970> all<00:08:04.479> of<00:08:04.599> them<00:08:04.780> the<00:08:05.530> most 00:08:05.879 --> 00:08:05.889 align:start position:0% into detail for all of them the most 00:08:05.889 --> 00:08:07.890 align:start position:0% into detail for all of them the most extensive<00:08:06.400> stage<00:08:06.909> is<00:08:07.090> the<00:08:07.180> last<00:08:07.360> one<00:08:07.539> here<00:08:07.750> the 00:08:07.890 --> 00:08:07.900 align:start position:0% extensive stage is the last one here the 00:08:07.900 --> 00:08:09.510 align:start position:0% extensive stage is the last one here the common<00:08:08.139> sub-expression<00:08:08.680> Eliminator<00:08:09.190> which 00:08:09.510 --> 00:08:09.520 align:start position:0% common sub-expression Eliminator which 00:08:09.520 --> 00:08:12.450 align:start position:0% common sub-expression Eliminator which does<00:08:10.270> much<00:08:10.659> more<00:08:10.690> than<00:08:11.229> what<00:08:12.130> the<00:08:12.280> name 00:08:12.450 --> 00:08:12.460 align:start position:0% does much more than what the name 00:08:12.460 --> 00:08:17.760 align:start position:0% does much more than what the name suggests<00:08:12.940> and<00:08:14.520> yeah<00:08:15.520> let's<00:08:16.320> dive<00:08:17.320> into<00:08:17.530> that<00:08:17.740> a 00:08:17.760 --> 00:08:17.770 align:start position:0% suggests and yeah let's dive into that a 00:08:17.770 --> 00:08:20.490 align:start position:0% suggests and yeah let's dive into that a little<00:08:17.949> so<00:08:18.820> what<00:08:19.030> it<00:08:19.120> does<00:08:19.270> is<00:08:19.479> first<00:08:19.960> it<00:08:20.229> chops 00:08:20.490 --> 00:08:20.500 align:start position:0% little so what it does is first it chops 00:08:20.500 --> 00:08:23.010 align:start position:0% little so what it does is first it chops code<00:08:20.860> so<00:08:21.310> it<00:08:21.400> gets<00:08:21.789> a<00:08:21.909> stream<00:08:22.240> of<00:08:22.389> op<00:08:22.509> codes<00:08:22.780> and 00:08:23.010 --> 00:08:23.020 align:start position:0% code so it gets a stream of op codes and 00:08:23.020 --> 00:08:25.499 align:start position:0% code so it gets a stream of op codes and chops<00:08:23.259> that<00:08:23.380> into<00:08:23.830> blocks<00:08:24.639> blocks<00:08:25.240> that<00:08:25.389> don't 00:08:25.499 --> 00:08:25.509 align:start position:0% chops that into blocks blocks that don't 00:08:25.509 --> 00:08:28.050 align:start position:0% chops that into blocks blocks that don't contain<00:08:25.930> jumps<00:08:26.800> don't<00:08:27.159> contain<00:08:27.490> external 00:08:28.050 --> 00:08:28.060 align:start position:0% contain jumps don't contain external 00:08:28.060 --> 00:08:30.899 align:start position:0% contain jumps don't contain external calls<00:08:28.300> and<00:08:28.599> some<00:08:28.810> other<00:08:28.960> restrictions<00:08:29.909> then 00:08:30.899 --> 00:08:30.909 align:start position:0% calls and some other restrictions then 00:08:30.909 --> 00:08:34.139 align:start position:0% calls and some other restrictions then these<00:08:31.469> blocks<00:08:32.469> are<00:08:32.740> fed<00:08:33.039> up<00:08:33.279> code<00:08:33.880> the<00:08:34.000> OP<00:08:34.120> code 00:08:34.139 --> 00:08:34.149 align:start position:0% these blocks are fed up code the OP code 00:08:34.149 --> 00:08:36.659 align:start position:0% these blocks are fed up code the OP code to<00:08:34.510> the<00:08:34.630> component<00:08:35.169> the<00:08:35.649> comment<00:08:36.039> component 00:08:36.659 --> 00:08:36.669 align:start position:0% to the component the comment component 00:08:36.669 --> 00:08:39.180 align:start position:0% to the component the comment component builds<00:08:37.000> symbolic<00:08:37.779> expression<00:08:38.229> trees<00:08:38.469> so 00:08:39.180 --> 00:08:39.190 align:start position:0% builds symbolic expression trees so 00:08:39.190 --> 00:08:41.790 align:start position:0% builds symbolic expression trees so analyzes<00:08:39.729> the<00:08:39.849> stack<00:08:40.029> usage<00:08:40.419> and<00:08:40.800> creates 00:08:41.790 --> 00:08:41.800 align:start position:0% analyzes the stack usage and creates 00:08:41.800 --> 00:08:43.890 align:start position:0% analyzes the stack usage and creates symbolic<00:08:42.159> expressions<00:08:42.579> out<00:08:42.700> of<00:08:42.849> them<00:08:43.029> then 00:08:43.890 --> 00:08:43.900 align:start position:0% symbolic expressions out of them then 00:08:43.900 --> 00:08:46.500 align:start position:0% symbolic expressions out of them then these<00:08:44.500> expression<00:08:45.040> trees<00:08:45.220> are<00:08:45.430> simplified<00:08:46.180> to 00:08:46.500 --> 00:08:46.510 align:start position:0% these expression trees are simplified to 00:08:46.510 --> 00:08:49.619 align:start position:0% these expression trees are simplified to I<00:08:47.020> think<00:08:47.670> 40<00:08:48.670> or<00:08:48.820> 50 00:08:49.619 --> 00:08:49.629 align:start position:0% I think 40 or 50 00:08:49.629 --> 00:08:53.479 align:start position:0% I think 40 or 50 simple<00:08:50.459> transformation<00:08:51.459> rules<00:08:51.699> like<00:08:52.350> yeah 00:08:53.479 --> 00:08:53.489 align:start position:0% simple transformation rules like yeah 00:08:53.489 --> 00:08:55.949 align:start position:0% simple transformation rules like yeah constant<00:08:54.489> plus<00:08:54.639> variable<00:08:55.029> plus<00:08:55.269> constant<00:08:55.600> is 00:08:55.949 --> 00:08:55.959 align:start position:0% constant plus variable plus constant is 00:08:55.959 --> 00:08:58.460 align:start position:0% constant plus variable plus constant is variable<00:08:56.739> plus<00:08:56.949> the<00:08:57.189> sum<00:08:57.399> of<00:08:57.429> the<00:08:57.610> constants 00:08:58.460 --> 00:08:58.470 align:start position:0% variable plus the sum of the constants 00:08:58.470 --> 00:09:02.340 align:start position:0% variable plus the sum of the constants and<00:08:59.470> so<00:08:59.649> on<00:09:00.149> these<00:09:01.149> rules<00:09:01.420> will<00:09:01.600> be<00:09:01.689> reused<00:09:02.110> by 00:09:02.340 --> 00:09:02.350 align:start position:0% and so on these rules will be reused by 00:09:02.350 --> 00:09:03.479 align:start position:0% and so on these rules will be reused by the<00:09:02.410> you'll<00:09:02.619> optimize<00:09:03.040> so<00:09:03.189> that's<00:09:03.369> not 00:09:03.479 --> 00:09:03.489 align:start position:0% the you'll optimize so that's not 00:09:03.489 --> 00:09:06.389 align:start position:0% the you'll optimize so that's not something<00:09:03.699> we<00:09:03.910> have<00:09:03.939> to<00:09:04.149> rewrite<00:09:04.480> and<00:09:05.399> after 00:09:06.389 --> 00:09:06.399 align:start position:0% something we have to rewrite and after 00:09:06.399 --> 00:09:09.929 align:start position:0% something we have to rewrite and after the<00:09:07.319> expression<00:09:08.319> fees<00:09:08.470> are<00:09:08.709> simplified<00:09:09.249> the 00:09:09.929 --> 00:09:09.939 align:start position:0% the expression fees are simplified the 00:09:09.939 --> 00:09:12.989 align:start position:0% the expression fees are simplified the component<00:09:10.509> records<00:09:11.439> all<00:09:12.009> changes<00:09:12.610> to<00:09:12.730> memory 00:09:12.989 --> 00:09:12.999 align:start position:0% component records all changes to memory 00:09:12.999 --> 00:09:15.090 align:start position:0% component records all changes to memory and<00:09:13.179> storage<00:09:13.389> in<00:09:13.689> an<00:09:13.779> abstract<00:09:14.049> way<00:09:14.379> so<00:09:14.649> both 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expressions yeah the problem with that 00:09:22.509 --> 00:09:25.889 align:start position:0% expressions yeah the problem with that is<00:09:22.809> that<00:09:23.189> it<00:09:24.189> kind<00:09:24.429> of<00:09:24.549> looks<00:09:24.790> like<00:09:24.910> this<00:09:25.209> so<00:09:25.569> on 00:09:25.889 --> 00:09:25.899 align:start position:0% is that it kind of looks like this so on 00:09:25.899 --> 00:09:27.689 align:start position:0% is that it kind of looks like this so on the<00:09:25.959> left<00:09:26.199> you<00:09:26.379> have<00:09:26.410> the<00:09:26.769> stream<00:09:27.129> of<00:09:27.249> opcodes 00:09:27.689 --> 00:09:27.699 align:start position:0% the left you have the stream of opcodes 00:09:27.699 --> 00:09:30.269 align:start position:0% the left you have the stream of opcodes and<00:09:27.970> on<00:09:28.119> the<00:09:28.209> right<00:09:28.420> you<00:09:29.290> have<00:09:29.319> some<00:09:29.470> kind<00:09:30.069> of 00:09:30.269 --> 00:09:30.279 align:start position:0% and on the right you have some kind of 00:09:30.279 --> 00:09:33.359 align:start position:0% and on the right you have some kind of explanation<00:09:31.209> of<00:09:31.720> what<00:09:32.139> the<00:09:32.350> component<00:09:33.009> has<00:09:33.100> to 00:09:33.359 --> 00:09:33.369 align:start position:0% explanation of what the component has to 00:09:33.369 --> 00:09:37.169 align:start position:0% explanation of what the component has to store<00:09:33.819> internally<00:09:34.769> in<00:09:35.769> the<00:09:35.980> end<00:09:36.249> we<00:09:36.369> can't<00:09:36.670> be 00:09:37.169 --> 00:09:37.179 align:start position:0% store internally in the end we can't be 00:09:37.179 --> 00:09:39.299 align:start position:0% store internally in the end we can't be yeah<00:09:37.689> there's<00:09:37.869> no<00:09:38.079> real<00:09:38.350> way<00:09:38.589> to<00:09:38.619> output<00:09:39.160> the 00:09:39.299 --> 00:09:39.309 align:start position:0% yeah there's no real way to output the 00:09:39.309 --> 00:09:41.189 align:start position:0% yeah there's no real way to output the internal<00:09:39.730> symbolic<00:09:40.239> representation<00:09:40.839> even<00:09:41.079> if 00:09:41.189 --> 00:09:41.199 align:start position:0% internal symbolic representation even if 00:09:41.199 --> 00:09:43.799 align:start position:0% internal symbolic representation even if there<00:09:41.559> was<00:09:41.920> such<00:09:42.160> a<00:09:42.189> way<00:09:42.489> it<00:09:43.329> would<00:09:43.540> be<00:09:43.660> very 00:09:43.799 --> 00:09:43.809 align:start position:0% there was such a way it would be very 00:09:43.809 --> 00:09:51.929 align:start position:0% there was such a way it would be very hard<00:09:44.079> to<00:09:44.230> read<00:09:45.059> and<00:09:49.170> yeah<00:09:50.170> so<00:09:50.790> yeah<00:09:51.790> the 00:09:51.929 --> 00:09:51.939 align:start position:0% hard to read and yeah so yeah the 00:09:51.939 --> 00:09:54.419 align:start position:0% hard to read and yeah so yeah the takeaway<00:09:52.420> from<00:09:53.019> the<00:09:53.170> old<00:09:53.319> CC<00:09:53.739> optimizer<00:09:54.129> is 00:09:54.419 --> 00:09:54.429 align:start position:0% takeaway from the old CC optimizer is 00:09:54.429 --> 00:09:57.059 align:start position:0% takeaway from the old CC optimizer is that<00:09:54.730> it<00:09:55.059> builds<00:09:55.419> a<00:09:55.779> gigantic<00:09:56.470> internal<00:09:56.919> data 00:09:57.059 --> 00:09:57.069 align:start position:0% that it builds a gigantic internal data 00:09:57.069 --> 00:10:04.859 align:start position:0% that it builds a gigantic internal data structure<00:09:57.549> yeah<00:09:59.279> yeah<00:10:01.350> and<00:10:03.689> after<00:10:04.689> it<00:10:04.749> has 00:10:04.859 --> 00:10:04.869 align:start position:0% structure yeah yeah and after it has 00:10:04.869 --> 00:10:07.650 align:start position:0% structure yeah yeah and after it has built<00:10:05.110> this<00:10:05.290> data<00:10:05.829> structure<00:10:06.160> it<00:10:06.660> regenerates 00:10:07.650 --> 00:10:07.660 align:start position:0% built this data structure it regenerates 00:10:07.660 --> 00:10:09.929 align:start position:0% built this data structure it regenerates the<00:10:07.779> code<00:10:08.079> from<00:10:08.439> scratch<00:10:08.619> so<00:10:09.220> it<00:10:09.429> starts<00:10:09.790> from 00:10:09.929 --> 00:10:09.939 align:start position:0% the code from scratch so it starts from 00:10:09.939 --> 00:10:14.519 align:start position:0% the code from scratch so it starts from the<00:10:10.059> bottom<00:10:10.179> up<00:10:10.480> and<00:10:12.779> takes<00:10:13.779> a<00:10:13.929> look<00:10:14.049> what<00:10:14.319> the 00:10:14.519 --> 00:10:14.529 align:start position:0% the bottom up and takes a look what the 00:10:14.529 --> 00:10:17.340 align:start position:0% the bottom up and takes a look what the desired<00:10:15.220> stack<00:10:15.879> elements<00:10:16.749> at<00:10:16.839> the<00:10:16.869> end<00:10:17.110> of 00:10:17.340 --> 00:10:17.350 align:start position:0% desired stack elements at the end of 00:10:17.350 --> 00:10:20.429 align:start position:0% desired stack elements at the end of this<00:10:17.529> chopped<00:10:18.429> up<00:10:18.579> block<00:10:18.970> would<00:10:19.600> be<00:10:19.629> then 00:10:20.429 --> 00:10:20.439 align:start position:0% this chopped up block would be then 00:10:20.439 --> 00:10:23.220 align:start position:0% this chopped up block would be then recreates<00:10:21.220> the<00:10:21.759> stack<00:10:22.089> elements<00:10:22.629> and<00:10:22.839> also 00:10:23.220 --> 00:10:23.230 align:start position:0% recreates the stack elements and also 00:10:23.230 --> 00:10:26.239 align:start position:0% recreates the stack elements and also recreates<00:10:24.220> changes<00:10:24.759> to<00:10:24.970> storage<00:10:25.419> and<00:10:25.660> memory 00:10:26.239 --> 00:10:26.249 align:start position:0% recreates changes to storage and memory 00:10:26.249 --> 00:10:30.359 align:start position:0% recreates changes to storage and memory in<00:10:27.249> a<00:10:27.489> more<00:10:27.699> efficient<00:10:28.059> way<00:10:28.230> because<00:10:29.230> it<00:10:30.220> will 00:10:30.359 --> 00:10:30.369 align:start position:0% in a more efficient way because it will 00:10:30.369 --> 00:10:33.299 align:start position:0% in a more efficient way because it will really<00:10:30.699> mean<00:10:30.790> a<00:10:31.029> limit<00:10:31.389> eliminate<00:10:32.309> multiple 00:10:33.299 --> 00:10:33.309 align:start position:0% really mean a limit eliminate multiple 00:10:33.309 --> 00:10:34.979 align:start position:0% really mean a limit eliminate multiple stores<00:10:33.549> to<00:10:33.819> the<00:10:33.850> same<00:10:34.089> storage<00:10:34.360> location<00:10:34.869> and 00:10:34.979 --> 00:10:34.989 align:start position:0% stores to the same storage location and 00:10:34.989 --> 00:10:36.359 align:start position:0% stores to the same storage location and multiple<00:10:35.319> memory<00:10:35.559> stores<00:10:35.919> to<00:10:36.100> the<00:10:36.160> same 00:10:36.359 --> 00:10:36.369 align:start position:0% multiple memory stores to the same 00:10:36.369 --> 00:10:39.929 align:start position:0% multiple memory stores to the same memory<00:10:36.639> location<00:10:36.699> and<00:10:37.299> also<00:10:38.230> if<00:10:38.439> you<00:10:38.589> have<00:10:39.369> if 00:10:39.929 --> 00:10:39.939 align:start position:0% memory location and also if you have if 00:10:39.939 --> 00:10:43.799 align:start position:0% memory location and also if you have if we<00:10:40.299> have<00:10:40.419> two<00:10:40.600> expressions<00:10:41.939> in<00:10:42.939> the<00:10:43.119> code<00:10:43.360> that 00:10:43.799 --> 00:10:43.809 align:start position:0% we have two expressions in the code that 00:10:43.809 --> 00:10:44.970 align:start position:0% we have two expressions in the code that do<00:10:43.929> the<00:10:44.019> same<00:10:44.199> thing<00:10:44.410> then<00:10:44.589> it's<00:10:44.829> only 00:10:44.970 --> 00:10:44.980 align:start position:0% do the same thing then it's only 00:10:44.980 --> 00:10:48.720 align:start position:0% do the same thing then it's only computed<00:10:45.399> once<00:10:46.980> and<00:10:47.980> yeah<00:10:48.279> as<00:10:48.369> I<00:10:48.459> said<00:10:48.519> the 00:10:48.720 --> 00:10:48.730 align:start position:0% computed once and yeah as I said the 00:10:48.730 --> 00:10:50.549 align:start position:0% computed once and yeah as I said the main<00:10:48.850> drawback<00:10:49.209> of<00:10:49.299> this<00:10:49.480> component<00:10:50.290> is<00:10:50.350> very 00:10:50.549 --> 00:10:50.559 align:start position:0% main drawback of this component is very 00:10:50.559 --> 00:10:55.159 align:start position:0% main drawback of this component is very opaque<00:10:52.559> also<00:10:53.559> it<00:10:53.649> is<00:10:53.799> only<00:10:53.980> very<00:10:54.189> local 00:10:55.159 --> 00:10:55.169 align:start position:0% opaque also it is only very local 00:10:55.169 --> 00:10:59.159 align:start position:0% opaque also it is only very local optimizations<00:10:56.169> only<00:10:57.129> inside<00:10:57.669> these<00:10:58.169> blocks 00:10:59.159 --> 00:10:59.169 align:start position:0% optimizations only inside these blocks 00:10:59.169 --> 00:11:02.519 align:start position:0% optimizations only inside these blocks it<00:10:59.919> has<00:11:00.279> no<00:11:01.240> notion<00:11:01.629> of<00:11:01.809> functions<00:11:02.350> so<00:11:02.470> it 00:11:02.519 --> 00:11:02.529 align:start position:0% it has no notion of functions so it 00:11:02.529 --> 00:11:03.070 align:start position:0% it has no notion of functions so it cannot 00:11:03.070 --> 00:11:03.080 align:start position:0% cannot 00:11:03.080 --> 00:11:05.710 align:start position:0% cannot inlining<00:11:03.740> and<00:11:04.100> also<00:11:04.640> cannot<00:11:04.820> do<00:11:04.970> any<00:11:05.149> loop 00:11:05.710 --> 00:11:05.720 align:start position:0% inlining and also cannot do any loop 00:11:05.720 --> 00:11:09.820 align:start position:0% inlining and also cannot do any loop optimizations<00:11:06.470> there<00:11:06.950> are<00:11:07.100> some<00:11:08.680> stages<00:11:09.680> in 00:11:09.820 --> 00:11:09.830 align:start position:0% optimizations there are some stages in 00:11:09.830 --> 00:11:12.820 align:start position:0% optimizations there are some stages in the<00:11:09.920> old<00:11:10.040> optimizer<00:11:10.550> that<00:11:11.240> look<00:11:11.959> beyond<00:11:12.500> these 00:11:12.820 --> 00:11:12.830 align:start position:0% the old optimizer that look beyond these 00:11:12.830 --> 00:11:18.180 align:start position:0% the old optimizer that look beyond these blocks<00:11:13.399> but<00:11:13.790> they<00:11:14.000> also<00:11:14.149> do<00:11:14.420> not<00:11:14.450> do<00:11:14.720> in<00:11:14.899> lining 00:11:18.180 --> 00:11:18.190 align:start position:0% 00:11:18.190 --> 00:11:21.040 align:start position:0% ok<00:11:19.190> now<00:11:19.370> let's<00:11:19.730> take<00:11:19.880> a<00:11:19.940> look<00:11:20.089> at<00:11:20.269> at<00:11:20.540> Yule<00:11:20.810> and 00:11:21.040 --> 00:11:21.050 align:start position:0% ok now let's take a look at at Yule and 00:11:21.050 --> 00:11:24.900 align:start position:0% ok now let's take a look at at Yule and what<00:11:21.350> the<00:11:21.529> new<00:11:21.680> optimizer<00:11:22.630> can<00:11:23.630> do<00:11:23.959> with<00:11:24.200> it 00:11:24.900 --> 00:11:24.910 align:start position:0% what the new optimizer can do with it 00:11:24.910 --> 00:11:27.310 align:start position:0% what the new optimizer can do with it there<00:11:25.910> has<00:11:26.240> been<00:11:26.390> a<00:11:26.450> talk<00:11:26.779> I<00:11:26.959> think<00:11:27.140> yesterday 00:11:27.310 --> 00:11:27.320 align:start position:0% there has been a talk I think yesterday 00:11:27.320 --> 00:11:30.160 align:start position:0% there has been a talk I think yesterday by<00:11:27.800> Alex<00:11:28.130> about<00:11:28.310> Yule<00:11:28.670> here<00:11:29.240> at<00:11:29.450> DEFCON<00:11:29.779> 4<00:11:30.019> and 00:11:30.160 --> 00:11:30.170 align:start position:0% by Alex about Yule here at DEFCON 4 and 00:11:30.170 --> 00:11:31.540 align:start position:0% by Alex about Yule here at DEFCON 4 and also<00:11:30.320> another<00:11:30.769> one<00:11:30.890> that<00:11:30.980> I've<00:11:31.130> confirmed 00:11:31.540 --> 00:11:31.550 align:start position:0% also another one that I've confirmed 00:11:31.550 --> 00:11:36.040 align:start position:0% also another one that I've confirmed last<00:11:31.760> year<00:11:33.430> we<00:11:34.430> are<00:11:34.610> already<00:11:34.940> using<00:11:35.269> Yule<00:11:35.779> in 00:11:36.040 --> 00:11:36.050 align:start position:0% last year we are already using Yule in 00:11:36.050 --> 00:11:40.319 align:start position:0% last year we are already using Yule in the<00:11:36.290> new<00:11:36.740> ABI<00:11:37.430> coder<00:11:37.880> and<00:11:38.230> the<00:11:39.230> plan<00:11:39.440> is<00:11:39.620> to<00:11:39.829> use 00:11:40.319 --> 00:11:40.329 align:start position:0% the new ABI coder and the plan is to use 00:11:40.329 --> 00:11:43.660 align:start position:0% the new ABI coder and the plan is to use Yule<00:11:41.329> for<00:11:41.540> everything<00:11:41.870> else<00:11:42.040> starting<00:11:43.040> next 00:11:43.660 --> 00:11:43.670 align:start position:0% Yule for everything else starting next 00:11:43.670 --> 00:11:47.019 align:start position:0% Yule for everything else starting next week<00:11:43.940> so<00:11:44.360> the<00:11:45.079> plan<00:11:45.350> is<00:11:45.380> to<00:11:45.640> rewrite<00:11:46.640> the<00:11:46.850> code 00:11:47.019 --> 00:11:47.029 align:start position:0% week so the plan is to rewrite the code 00:11:47.029 --> 00:11:49.780 align:start position:0% week so the plan is to rewrite the code generator<00:11:47.420> of<00:11:47.630> solidity<00:11:48.050> using<00:11:48.709> Yule<00:11:48.860> so<00:11:49.610> that 00:11:49.780 --> 00:11:49.790 align:start position:0% generator of solidity using Yule so that 00:11:49.790 --> 00:11:54.460 align:start position:0% generator of solidity using Yule so that it<00:11:49.970> can<00:11:50.950> target<00:11:51.950> both<00:11:52.820> EVM<00:11:53.420> and<00:11:53.750> web<00:11:53.990> assembly 00:11:54.460 --> 00:11:54.470 align:start position:0% it can target both EVM and web assembly 00:11:54.470 --> 00:11:57.280 align:start position:0% it can target both EVM and web assembly and<00:11:54.820> we<00:11:55.820> will<00:11:55.940> also<00:11:56.209> be<00:11:56.300> able<00:11:56.540> to<00:11:56.600> use<00:11:56.779> the 00:11:57.280 --> 00:11:57.290 align:start position:0% and we will also be able to use the 00:11:57.290 --> 00:12:00.130 align:start position:0% and we will also be able to use the optimizer<00:11:57.709> for<00:11:57.860> all<00:11:58.339> of<00:11:58.850> the<00:11:59.089> the<00:11:59.120> code<00:11:59.990> that 00:12:00.130 --> 00:12:00.140 align:start position:0% optimizer for all of the the code that 00:12:00.140 --> 00:12:02.440 align:start position:0% optimizer for all of the the code that solidity<00:12:00.470> generates<00:12:00.920> not<00:12:01.100> only<00:12:01.459> for<00:12:02.029> the<00:12:02.209> ABI 00:12:02.440 --> 00:12:02.450 align:start position:0% solidity generates not only for the ABI 00:12:02.450 --> 00:12:07.410 align:start position:0% solidity generates not only for the ABI coder<00:12:04.390> yeah<00:12:05.390> you'll<00:12:05.720> has<00:12:05.930> a<00:12:05.959> simple<00:12:06.649> syntax 00:12:07.410 --> 00:12:07.420 align:start position:0% coder yeah you'll has a simple syntax 00:12:07.420 --> 00:12:10.180 align:start position:0% coder yeah you'll has a simple syntax has<00:12:08.420> structural<00:12:08.870> components<00:12:09.529> and<00:12:09.740> I<00:12:09.920> think 00:12:10.180 --> 00:12:10.190 align:start position:0% has structural components and I think 00:12:10.190 --> 00:12:15.010 align:start position:0% has structural components and I think it's<00:12:11.170> quite<00:12:12.170> intuitive<00:12:12.529> to<00:12:12.920> read<00:12:13.720> but<00:12:14.720> yeah 00:12:15.010 --> 00:12:15.020 align:start position:0% it's quite intuitive to read but yeah 00:12:15.020 --> 00:12:17.079 align:start position:0% it's quite intuitive to read but yeah I'm<00:12:15.980> already<00:12:16.279> spending<00:12:16.640> too<00:12:16.730> much<00:12:16.790> time<00:12:16.940> on 00:12:17.079 --> 00:12:17.089 align:start position:0% I'm already spending too much time on 00:12:17.089 --> 00:12:19.510 align:start position:0% I'm already spending too much time on that<00:12:17.209> so<00:12:17.990> let's<00:12:18.589> take<00:12:18.800> a<00:12:18.829> look<00:12:18.980> what<00:12:19.160> the 00:12:19.510 --> 00:12:19.520 align:start position:0% that so let's take a look what the 00:12:19.520 --> 00:12:25.660 align:start position:0% that so let's take a look what the optimizer<00:12:20.270> itself<00:12:22.779> instead<00:12:23.779> of<00:12:24.550> building<00:12:25.550> a 00:12:25.660 --> 00:12:25.670 align:start position:0% optimizer itself instead of building a 00:12:25.670 --> 00:12:28.740 align:start position:0% optimizer itself instead of building a component<00:12:26.029> that<00:12:26.420> looks<00:12:27.140> at<00:12:27.560> the<00:12:28.010> code<00:12:28.220> and 00:12:28.740 --> 00:12:28.750 align:start position:0% component that looks at the code and 00:12:28.750 --> 00:12:31.960 align:start position:0% component that looks at the code and assembles<00:12:29.750> tons<00:12:30.020> of<00:12:30.200> information<00:12:31.040> we<00:12:31.850> decided 00:12:31.960 --> 00:12:31.970 align:start position:0% assembles tons of information we decided 00:12:31.970 --> 00:12:34.420 align:start position:0% assembles tons of information we decided to<00:12:32.630> instead<00:12:33.230> replace<00:12:33.649> it<00:12:33.890> by<00:12:34.010> a<00:12:34.040> component 00:12:34.420 --> 00:12:34.430 align:start position:0% to instead replace it by a component 00:12:34.430 --> 00:12:39.340 align:start position:0% to instead replace it by a component that<00:12:34.610> performs<00:12:36.130> many<00:12:37.130> tiny<00:12:38.350> local 00:12:39.340 --> 00:12:39.350 align:start position:0% that performs many tiny local 00:12:39.350 --> 00:12:44.440 align:start position:0% that performs many tiny local transformations<00:12:40.100> to<00:12:41.029> the<00:12:41.060> code<00:12:41.529> so<00:12:43.450> every 00:12:44.440 --> 00:12:44.450 align:start position:0% transformations to the code so every 00:12:44.450 --> 00:12:46.210 align:start position:0% transformations to the code so every single<00:12:44.959> step<00:12:45.260> of<00:12:45.440> the<00:12:45.560> component<00:12:46.040> there's 00:12:46.210 --> 00:12:46.220 align:start position:0% single step of the component there's 00:12:46.220 --> 00:12:48.790 align:start position:0% single step of the component there's only<00:12:46.430> one<00:12:47.089> so<00:12:47.510> every<00:12:47.750> single<00:12:47.899> step<00:12:48.140> of<00:12:48.290> every 00:12:48.790 --> 00:12:48.800 align:start position:0% only one so every single step of every 00:12:48.800 --> 00:12:51.100 align:start position:0% only one so every single step of every single<00:12:49.370> component<00:12:49.880> of<00:12:50.270> the<00:12:50.540> optimizer 00:12:51.100 --> 00:12:51.110 align:start position:0% single component of the optimizer 00:12:51.110 --> 00:12:53.439 align:start position:0% single component of the optimizer there's<00:12:51.829> only<00:12:51.980> one<00:12:52.279> single<00:12:52.579> thing<00:12:52.880> only<00:12:53.120> one 00:12:53.439 --> 00:12:53.449 align:start position:0% there's only one single thing only one 00:12:53.449 --> 00:12:57.220 align:start position:0% there's only one single thing only one small<00:12:54.020> transformation<00:12:54.980> on<00:12:55.160> the<00:12:55.930> yule<00:12:56.930> code 00:12:57.220 --> 00:12:57.230 align:start position:0% small transformation on the yule code 00:12:57.230 --> 00:12:59.410 align:start position:0% small transformation on the yule code and<00:12:57.500> the<00:12:58.040> output<00:12:58.459> of<00:12:58.490> each<00:12:58.699> of<00:12:58.880> the<00:12:59.000> steps<00:12:59.240> is 00:12:59.410 --> 00:12:59.420 align:start position:0% and the output of each of the steps is 00:12:59.420 --> 00:13:05.139 align:start position:0% and the output of each of the steps is always<00:12:59.810> again<00:13:00.529> Google<00:13:00.860> code<00:13:01.040> so<00:13:01.250> it<00:13:01.370> always<00:13:04.149> it 00:13:05.139 --> 00:13:05.149 align:start position:0% always again Google code so it always it 00:13:05.149 --> 00:13:06.790 align:start position:0% always again Google code so it always it is<00:13:05.209> always<00:13:05.420> readable<00:13:05.990> it<00:13:06.110> is<00:13:06.199> still<00:13:06.410> text 00:13:06.790 --> 00:13:06.800 align:start position:0% is always readable it is still text 00:13:06.800 --> 00:13:09.160 align:start position:0% is always readable it is still text there<00:13:07.040> are<00:13:07.160> no<00:13:07.339> internal<00:13:07.910> big<00:13:08.630> internal<00:13:08.990> data 00:13:09.160 --> 00:13:09.170 align:start position:0% there are no internal big internal data 00:13:09.170 --> 00:13:14.350 align:start position:0% there are no internal big internal data structures<00:13:09.649> and<00:13:12.579> at<00:13:13.579> every<00:13:13.850> time<00:13:14.060> you<00:13:14.209> can 00:13:14.350 --> 00:13:14.360 align:start position:0% structures and at every time you can 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it<00:13:20.570> keeps 00:13:20.710 --> 00:13:20.720 align:start position:0% structure of the code so it keeps 00:13:20.720 --> 00:13:23.019 align:start position:0% structure of the code so it keeps functions<00:13:21.230> and<00:13:21.470> loops<00:13:22.160> it<00:13:22.700> does<00:13:22.880> not 00:13:23.019 --> 00:13:23.029 align:start position:0% functions and loops it does not 00:13:23.029 --> 00:13:25.660 align:start position:0% functions and loops it does not introduce<00:13:23.240> go<00:13:23.600> tools<00:13:23.870> and<00:13:24.110> this<00:13:24.649> helps<00:13:24.980> us<00:13:25.190> for 00:13:25.660 --> 00:13:25.670 align:start position:0% introduce go tools and this helps us for 00:13:25.670 --> 00:13:27.069 align:start position:0% introduce go tools and this helps us for the<00:13:25.850> translation<00:13:26.300> to<00:13:26.360> webassembly<00:13:26.690> because 00:13:27.069 --> 00:13:27.079 align:start position:0% the translation to webassembly because 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it's<00:13:38.810> not<00:13:39.100> designing<00:13:40.100> the 00:13:40.420 --> 00:13:40.430 align:start position:0% optimizer is when it's not designing the 00:13:40.430 --> 00:13:41.920 align:start position:0% optimizer is when it's not designing the components<00:13:40.970> but<00:13:41.120> coming<00:13:41.540> up<00:13:41.630> with<00:13:41.779> a<00:13:41.810> good 00:13:41.920 --> 00:13:41.930 align:start position:0% components but coming up with a good 00:13:41.930 --> 00:13:44.040 align:start position:0% components but coming up with a good strategy<00:13:42.140> on<00:13:42.500> when<00:13:42.709> to<00:13:42.860> call<00:13:43.040> each<00:13:43.250> component 00:13:44.040 --> 00:13:44.050 align:start position:0% strategy on when to call each component 00:13:44.050 --> 00:13:47.410 align:start position:0% strategy on when to call each component but<00:13:45.050> the<00:13:45.200> good<00:13:45.380> news<00:13:45.410> here<00:13:45.920> is<00:13:45.950> that<00:13:46.120> even<00:13:47.120> if 00:13:47.410 --> 00:13:47.420 align:start position:0% but the good news here is that even if 00:13:47.420 --> 00:13:50.290 align:start position:0% but the good news here is that even if this<00:13:47.829> this<00:13:48.829> strategy<00:13:49.370> turns<00:13:49.970> out<00:13:50.149> to<00:13:50.269> be 00:13:50.290 --> 00:13:50.300 align:start position:0% this this strategy turns out to be 00:13:50.300 --> 00:13:52.840 align:start position:0% this this strategy turns out to be suboptimal<00:13:50.899> it<00:13:51.320> will<00:13:51.620> never<00:13:52.010> result<00:13:52.730> in 00:13:52.840 --> 00:13:52.850 align:start position:0% suboptimal it will never result in 00:13:52.850 --> 00:13:57.579 align:start position:0% suboptimal it will never result in invalid<00:13:53.450> code<00:13:53.630> because<00:13:53.990> as<00:13:54.320> long<00:13:55.040> as<00:13:55.100> we<00:13:56.589> check 00:13:57.579 --> 00:13:57.589 align:start position:0% invalid code because as long as we check 00:13:57.589 --> 00:13:59.319 align:start position:0% invalid code because as long as we check that<00:13:57.800> every<00:13:58.100> of<00:13:58.250> these<00:13:58.430> small<00:13:59.029> time 00:13:59.319 --> 00:13:59.329 align:start position:0% that every of these small time 00:13:59.329 --> 00:14:02.250 align:start position:0% that every of these small time transformations<00:14:00.250> does<00:14:01.250> its<00:14:01.430> job<00:14:01.490> correctly 00:14:02.250 --> 00:14:02.260 align:start position:0% transformations does its job correctly 00:14:02.260 --> 00:14:04.960 align:start position:0% transformations does its job correctly then<00:14:03.260> any<00:14:03.740> combination<00:14:04.310> of<00:14:04.370> these<00:14:04.519> steps<00:14:04.760> will 00:14:04.960 --> 00:14:04.970 align:start position:0% then any combination of these steps will 00:14:04.970 --> 00:14:06.670 align:start position:0% then any combination of these steps will always<00:14:05.240> result<00:14:05.600> it<00:14:05.839> will<00:14:05.959> also<00:14:06.230> result<00:14:06.380> in 00:14:06.670 --> 00:14:06.680 align:start position:0% always result it will also result in 00:14:06.680 --> 00:14:08.889 align:start position:0% always result it will also result in correct<00:14:07.040> code<00:14:07.220> it<00:14:07.459> might<00:14:07.610> be<00:14:07.820> less<00:14:08.510> efficient 00:14:08.889 --> 00:14:08.899 align:start position:0% correct code it might be less efficient 00:14:08.899 --> 00:14:11.560 align:start position:0% correct code it might be less efficient but<00:14:08.959> it<00:14:09.110> will<00:14:09.200> always<00:14:09.320> be<00:14:09.440> correct<00:14:10.420> okay<00:14:11.420> now 00:14:11.560 --> 00:14:11.570 align:start position:0% but it will always be correct okay now 00:14:11.570 --> 00:14:13.630 align:start position:0% but it will always be correct okay now let's<00:14:12.140> take<00:14:12.260> an<00:14:12.380> example<00:14:12.440> let's<00:14:13.339> take<00:14:13.459> a<00:14:13.519> look 00:14:13.630 --> 00:14:13.640 align:start position:0% let's take an example let's take a look 00:14:13.640 --> 00:14:15.910 align:start position:0% let's take an example let's take a look at<00:14:13.730> example<00:14:14.149> this<00:14:14.810> is<00:14:15.140> your<00:14:15.529> code<00:14:15.890> that 00:14:15.910 --> 00:14:15.920 align:start position:0% at example this is your code that 00:14:15.920 --> 00:14:18.430 align:start position:0% at example this is your code that computes<00:14:16.550> the<00:14:16.970> sum<00:14:17.149> of<00:14:17.269> an<00:14:17.390> array<00:14:17.630> so<00:14:18.200> we<00:14:18.230> have 00:14:18.430 --> 00:14:18.440 align:start position:0% computes the sum of an array so we have 00:14:18.440 --> 00:14:21.460 align:start position:0% computes the sum of an array so we have the<00:14:18.560> first<00:14:18.769> function<00:14:18.950> that<00:14:19.510> has<00:14:20.510> a<00:14:20.540> for<00:14:21.230> loop 00:14:21.460 --> 00:14:21.470 align:start position:0% the first function that has a for loop 00:14:21.470 --> 00:14:24.639 align:start position:0% the first function that has a for loop over<00:14:21.680> the<00:14:21.949> array<00:14:22.370> elements<00:14:23.029> and<00:14:23.360> this<00:14:24.290> first 00:14:24.639 --> 00:14:24.649 align:start position:0% over the array elements and this first 00:14:24.649 --> 00:14:27.400 align:start position:0% over the array elements and this first function<00:14:25.130> calls<00:14:25.940> the<00:14:26.300> second<00:14:26.660> function<00:14:26.870> and 00:14:27.400 --> 00:14:27.410 align:start position:0% function calls the second function and 00:14:27.410 --> 00:14:31.060 align:start position:0% function calls the second function and the<00:14:28.190> second<00:14:28.459> function<00:14:29.380> retrieves<00:14:30.380> a<00:14:30.680> single 00:14:31.060 --> 00:14:31.070 align:start position:0% the second function retrieves a single 00:14:31.070 --> 00:14:33.040 align:start position:0% the second function retrieves a single array<00:14:31.279> element<00:14:31.670> so<00:14:31.820> access<00:14:32.240> the<00:14:32.360> array<00:14:32.630> and<00:14:32.870> I 00:14:33.040 --> 00:14:33.050 align:start position:0% array element so access the array and I 00:14:33.050 --> 00:14:36.370 align:start position:0% array element so access the array and I is<00:14:33.110> the<00:14:33.410> position<00:14:34.130> in<00:14:34.880> the<00:14:35.180> array<00:14:35.380> the 00:14:36.370 --> 00:14:36.380 align:start position:0% is the position in the array the 00:14:36.380 --> 00:14:37.810 align:start position:0% is the position in the array the interesting<00:14:36.740> thing<00:14:36.920> here<00:14:37.100> is<00:14:37.279> that<00:14:37.310> a<00:14:37.550> ray 00:14:37.810 --> 00:14:37.820 align:start position:0% interesting thing here is that a ray 00:14:37.820 --> 00:14:42.460 align:start position:0% interesting thing here is that a ray load<00:14:38.060> performs<00:14:38.540> bounds<00:14:38.899> checking<00:14:39.260> so<00:14:41.470> array 00:14:42.460 --> 00:14:42.470 align:start position:0% load performs bounds checking so array 00:14:42.470 --> 00:14:46.120 align:start position:0% load performs bounds checking so array load<00:14:43.449> checks<00:14:44.449> whether<00:14:44.720> I<00:14:44.810> is<00:14:45.019> less<00:14:45.560> than<00:14:45.620> the 00:14:46.120 --> 00:14:46.130 align:start position:0% load checks whether I is less than the 00:14:46.130 --> 00:14:50.980 align:start position:0% load checks whether I is less than the length<00:14:46.310> of<00:14:46.519> the<00:14:46.699> array<00:14:46.940> and<00:14:48.610> this<00:14:49.610> in<00:14:50.120> the<00:14:50.750> form 00:14:50.980 --> 00:14:50.990 align:start position:0% length of the array and this in the form 00:14:50.990 --> 00:14:52.389 align:start position:0% length of the array and this in the form here<00:14:51.230> it's<00:14:51.410> inefficient<00:14:51.709> because<00:14:51.980> it's<00:14:52.279> done 00:14:52.389 --> 00:14:52.399 align:start position:0% here it's inefficient because it's done 00:14:52.399 --> 00:14:55.720 align:start position:0% here it's inefficient because it's done in<00:14:52.519> every<00:14:52.640> single<00:14:53.149> loop<00:14:53.480> iteration<00:14:53.990> but<00:14:54.589> it<00:14:55.550> is 00:14:55.720 --> 00:14:55.730 align:start position:0% in every single loop iteration but it is 00:14:55.730 --> 00:14:58.389 align:start position:0% in every single loop iteration but it is very<00:14:56.329> safe<00:14:56.540> because<00:14:56.810> we<00:14:57.260> do<00:14:57.740> it<00:14:57.920> every<00:14:58.100> single 00:14:58.389 --> 00:14:58.399 align:start position:0% very safe because we do it every single 00:14:58.399 --> 00:15:00.519 align:start position:0% very safe because we do it every single loop<00:14:58.579> iteration<00:14:59.029> and<00:14:59.209> the<00:14:59.839> cool<00:14:59.990> thing<00:15:00.199> now<00:15:00.230> is 00:15:00.519 --> 00:15:00.529 align:start position:0% loop iteration and the cool thing now is 00:15:00.529 --> 00:15:02.199 align:start position:0% loop iteration and the cool thing now is that<00:15:00.560> we<00:15:00.740> will<00:15:00.980> see<00:15:01.130> that<00:15:01.339> the<00:15:01.699> optimizer<00:15:02.060> is 00:15:02.199 --> 00:15:02.209 align:start position:0% that we will see that the optimizer is 00:15:02.209 --> 00:15:05.829 align:start position:0% that we will see that the optimizer is able<00:15:02.540> to<00:15:03.100> remove<00:15:04.100> these<00:15:04.850> bounds<00:15:05.300> checks<00:15:05.540> with 00:15:05.829 --> 00:15:05.839 align:start position:0% able to remove these bounds checks with 00:15:05.839 --> 00:15:08.530 align:start position:0% able to remove these bounds checks with equivalent<00:15:06.339> transformations<00:15:07.339> so<00:15:08.180> the<00:15:08.329> first 00:15:08.530 --> 00:15:08.540 align:start position:0% equivalent transformations so the first 00:15:08.540 --> 00:15:10.780 align:start position:0% equivalent transformations so the first thing<00:15:08.750> that<00:15:09.199> happens<00:15:09.560> is<00:15:09.709> that<00:15:09.890> we<00:15:09.949> explode 00:15:10.780 --> 00:15:10.790 align:start position:0% thing that happens is that we explode 00:15:10.790 --> 00:15:13.720 align:start position:0% thing that happens is that we explode this<00:15:11.149> large<00:15:11.990> expression<00:15:12.920> into<00:15:13.430> an 00:15:13.720 --> 00:15:13.730 align:start position:0% this large expression into an 00:15:13.730 --> 00:15:17.230 align:start position:0% this large expression into an intermediate<00:15:14.589> assignment<00:15:15.589> and<00:15:15.910> now<00:15:16.910> we<00:15:16.970> have 00:15:17.230 --> 00:15:17.240 align:start position:0% intermediate assignment and now we have 00:15:17.240 --> 00:15:20.680 align:start position:0% intermediate assignment and now we have the<00:15:17.720> the<00:15:18.110> function<00:15:18.290> call<00:15:18.620> isolated<00:15:19.279> and<00:15:19.690> since 00:15:20.680 --> 00:15:20.690 align:start position:0% the the function call isolated and since 00:15:20.690 --> 00:15:21.970 align:start position:0% the the function call isolated and since it's<00:15:20.839> only<00:15:20.930> called<00:15:21.320> the<00:15:21.529> since<00:15:21.709> the<00:15:21.829> function 00:15:21.970 --> 00:15:21.980 align:start position:0% it's only called the since the function 00:15:21.980 --> 00:15:24.370 align:start position:0% it's only called the since the function is<00:15:22.190> only<00:15:22.279> called<00:15:22.579> once<00:15:22.790> we<00:15:23.570> can<00:15:23.720> inline<00:15:23.990> it<00:15:24.140> so 00:15:24.370 --> 00:15:24.380 align:start position:0% is only called once we can inline it so 00:15:24.380 --> 00:15:26.319 align:start position:0% is only called once we can inline it so we<00:15:24.560> can<00:15:24.740> replace<00:15:24.980> the<00:15:25.220> function<00:15:25.550> call<00:15:25.760> by<00:15:26.300> the 00:15:26.319 --> 00:15:26.329 align:start position:0% we can replace the function call by the 00:15:26.329 --> 00:15:29.079 align:start position:0% we can replace the function call by the body<00:15:26.660> of<00:15:26.839> the<00:15:26.959> function<00:15:27.140> so<00:15:27.380> that's<00:15:28.060> any<00:15:29.060> more 00:15:29.079 --> 00:15:29.089 align:start position:0% body of the function so that's any more 00:15:29.089 --> 00:15:30.470 align:start position:0% body of the function so that's any more drastic<00:15:29.660> change<00:15:29.959> to<00:15:30.199> the 00:15:30.470 --> 00:15:30.480 align:start position:0% drastic change to the 00:15:30.480 --> 00:15:35.180 align:start position:0% drastic change to the but<00:15:31.079> it's<00:15:31.440> simple<00:15:31.769> enough<00:15:31.860> and<00:15:33.680> now<00:15:34.680> the<00:15:34.740> next 00:15:35.180 --> 00:15:35.190 align:start position:0% but it's simple enough and now the next 00:15:35.190 --> 00:15:36.560 align:start position:0% but it's simple enough and now the next thing<00:15:35.430> that<00:15:35.490> happens<00:15:35.880> is<00:15:35.970> we<00:15:36.120> remove<00:15:36.389> this 00:15:36.560 --> 00:15:36.570 align:start position:0% thing that happens is we remove this 00:15:36.570 --> 00:15:40.639 align:start position:0% thing that happens is we remove this useless<00:15:37.339> additional<00:15:38.339> indented<00:15:39.209> block<00:15:39.389> and<00:15:39.810> we 00:15:40.639 --> 00:15:40.649 align:start position:0% useless additional indented block and we 00:15:40.649 --> 00:15:44.420 align:start position:0% useless additional indented block and we also<00:15:40.920> rename<00:15:41.339> one<00:15:41.820> of<00:15:42.060> the<00:15:42.180> variables<00:15:43.430> okay 00:15:44.420 --> 00:15:44.430 align:start position:0% also rename one of the variables okay 00:15:44.430 --> 00:15:46.250 align:start position:0% also rename one of the variables okay now<00:15:44.579> it's<00:15:44.760> already<00:15:45.660> a<00:15:45.750> little<00:15:45.930> bit<00:15:46.019> clearer 00:15:46.250 --> 00:15:46.260 align:start position:0% now it's already a little bit clearer 00:15:46.260 --> 00:15:48.639 align:start position:0% now it's already a little bit clearer now<00:15:47.070> we<00:15:47.130> change<00:15:47.519> the<00:15:47.579> formatting<00:15:47.940> a<00:15:48.089> little 00:15:48.639 --> 00:15:48.649 align:start position:0% now we change the formatting a little 00:15:48.649 --> 00:15:53.420 align:start position:0% now we change the formatting a little okay<00:15:49.649> so<00:15:50.600> this<00:15:51.600> was<00:15:51.810> already<00:15:52.100> one<00:15:53.100> of<00:15:53.190> the<00:15:53.310> two 00:15:53.420 --> 00:15:53.430 align:start position:0% okay so this was already one of the two 00:15:53.430 --> 00:15:56.689 align:start position:0% okay so this was already one of the two tricky<00:15:53.699> parts<00:15:54.000> now<00:15:54.870> what<00:15:55.440> happens<00:15:55.769> next<00:15:56.399> is 00:15:56.689 --> 00:15:56.699 align:start position:0% tricky parts now what happens next is 00:15:56.699 --> 00:15:59.240 align:start position:0% tricky parts now what happens next is that<00:15:56.810> we<00:15:57.810> take<00:15:57.990> a<00:15:58.019> look<00:15:58.260> at<00:15:58.500> all<00:15:58.889> the 00:15:59.240 --> 00:15:59.250 align:start position:0% that we take a look at all the 00:15:59.250 --> 00:16:01.579 align:start position:0% that we take a look at all the statements<00:15:59.790> inside<00:16:00.420> the<00:16:00.480> loop<00:16:00.810> buddy<00:16:01.050> and<00:16:01.320> see 00:16:01.579 --> 00:16:01.589 align:start position:0% statements inside the loop buddy and see 00:16:01.589 --> 00:16:04.129 align:start position:0% statements inside the loop buddy and see if<00:16:01.880> some<00:16:02.880> of<00:16:02.970> the<00:16:03.060> statements<00:16:03.510> don't<00:16:03.720> actually 00:16:04.129 --> 00:16:04.139 align:start position:0% if some of the statements don't actually 00:16:04.139 --> 00:16:08.540 align:start position:0% if some of the statements don't actually depend<00:16:04.470> on<00:16:04.740> the<00:16:05.010> iteration<00:16:05.519> at<00:16:05.610> all<00:16:05.760> so<00:16:07.550> the 00:16:08.540 --> 00:16:08.550 align:start position:0% depend on the iteration at all so the 00:16:08.550 --> 00:16:10.340 align:start position:0% depend on the iteration at all so the only<00:16:08.699> variable<00:16:09.240> that<00:16:09.269> is<00:16:09.480> reassigned<00:16:09.930> inside 00:16:10.340 --> 00:16:10.350 align:start position:0% only variable that is reassigned inside 00:16:10.350 --> 00:16:14.180 align:start position:0% only variable that is reassigned inside the<00:16:10.500> loop<00:16:10.649> is<00:16:10.889> some<00:16:11.550> and<00:16:11.850> I<00:16:12.170> so<00:16:13.190> everything 00:16:14.180 --> 00:16:14.190 align:start position:0% the loop is some and I so everything 00:16:14.190 --> 00:16:16.340 align:start position:0% the loop is some and I so everything that<00:16:14.220> is<00:16:14.370> not<00:16:14.579> depend<00:16:15.000> on<00:16:15.149> some<00:16:15.449> or<00:16:15.690> I<00:16:15.750> or 00:16:16.340 --> 00:16:16.350 align:start position:0% that is not depend on some or I or 00:16:16.350 --> 00:16:18.079 align:start position:0% that is not depend on some or I or anything<00:16:16.589> that<00:16:16.740> depends<00:16:17.160> on<00:16:17.250> somewhere<00:16:17.490> I<00:16:17.550> can 00:16:18.079 --> 00:16:18.089 align:start position:0% anything that depends on somewhere I can 00:16:18.089 --> 00:16:20.030 align:start position:0% anything that depends on somewhere I can be<00:16:18.240> pulled<00:16:18.510> out<00:16:18.720> of<00:16:18.750> the<00:16:19.019> loop<00:16:19.170> and<00:16:19.320> that's<00:16:19.740> not 00:16:20.030 --> 00:16:20.040 align:start position:0% be pulled out of the loop and that's not 00:16:20.040 --> 00:16:22.160 align:start position:0% be pulled out of the loop and that's not executed<00:16:20.880> for<00:16:21.029> every<00:16:21.240> single<00:16:21.600> loop<00:16:21.720> iteration 00:16:22.160 --> 00:16:22.170 align:start position:0% executed for every single loop iteration 00:16:22.170 --> 00:16:25.329 align:start position:0% executed for every single loop iteration but<00:16:22.290> only<00:16:22.470> once<00:16:23.089> before<00:16:24.089> the<00:16:24.389> loop<00:16:24.420> starts 00:16:25.329 --> 00:16:25.339 align:start position:0% but only once before the loop starts 00:16:25.339 --> 00:16:29.050 align:start position:0% but only once before the loop starts okay<00:16:26.339> so<00:16:27.089> there<00:16:27.240> was<00:16:27.360> data<00:16:27.600> and<00:16:27.810> Len<00:16:27.990> now<00:16:28.860> we 00:16:29.050 --> 00:16:29.060 align:start position:0% okay so there was data and Len now we 00:16:29.060 --> 00:16:31.879 align:start position:0% okay so there was data and Len now we realized<00:16:30.060> that<00:16:30.360> length<00:16:30.899> and<00:16:31.230> length<00:16:31.440> they<00:16:31.860> are 00:16:31.879 --> 00:16:31.889 align:start position:0% realized that length and length they are 00:16:31.889 --> 00:16:35.600 align:start position:0% realized that length and length they are assigned<00:16:32.519> the<00:16:32.790> same<00:16:33.000> value<00:16:33.860> sits<00:16:34.860> since<00:16:35.279> it's 00:16:35.600 --> 00:16:35.610 align:start position:0% assigned the same value sits since it's 00:16:35.610 --> 00:16:40.579 align:start position:0% assigned the same value sits since it's a<00:16:35.790> memory<00:16:36.149> load<00:16:36.860> it's<00:16:38.209> it<00:16:39.209> might<00:16:39.600> not<00:16:39.990> be<00:16:40.320> the 00:16:40.579 --> 00:16:40.589 align:start position:0% a memory load it's it might not be the 00:16:40.589 --> 00:16:43.370 align:start position:0% a memory load it's it might not be the same<00:16:40.769> value<00:16:41.010> in<00:16:41.279> the<00:16:41.399> end<00:16:41.959> but<00:16:42.959> if<00:16:43.079> the<00:16:43.230> memory 00:16:43.370 --> 00:16:43.380 align:start position:0% same value in the end but if the memory 00:16:43.380 --> 00:16:45.230 align:start position:0% same value in the end but if the memory does<00:16:43.680> not<00:16:43.860> change<00:16:44.100> between<00:16:44.459> these<00:16:44.760> two<00:16:44.940> memory 00:16:45.230 --> 00:16:45.240 align:start position:0% does not change between these two memory 00:16:45.240 --> 00:16:47.509 align:start position:0% does not change between these two memory load<00:16:45.420> operations<00:16:45.990> then<00:16:46.260> of<00:16:46.890> course<00:16:47.160> it<00:16:47.220> has<00:16:47.279> to 00:16:47.509 --> 00:16:47.519 align:start position:0% load operations then of course it has to 00:16:47.519 --> 00:16:49.009 align:start position:0% load operations then of course it has to be<00:16:47.579> the<00:16:47.699> same<00:16:47.880> value<00:16:48.180> and<00:16:48.360> this<00:16:48.570> is<00:16:48.630> the<00:16:48.839> case 00:16:49.009 --> 00:16:49.019 align:start position:0% be the same value and this is the case 00:16:49.019 --> 00:16:54.259 align:start position:0% be the same value and this is the case here<00:16:49.290> so<00:16:49.350> we<00:16:49.709> do<00:16:49.829> not<00:16:49.980> modify<00:16:50.250> memory<00:16:53.029> so<00:16:54.029> Len 00:16:54.259 --> 00:16:54.269 align:start position:0% here so we do not modify memory so Len 00:16:54.269 --> 00:16:55.759 align:start position:0% here so we do not modify memory so Len and<00:16:54.480> length<00:16:54.660> are<00:16:54.899> actually<00:16:55.260> the<00:16:55.350> same<00:16:55.380> thing 00:16:55.759 --> 00:16:55.769 align:start position:0% and length are actually the same thing 00:16:55.769 --> 00:16:59.090 align:start position:0% and length are actually the same thing which<00:16:56.519> means<00:16:56.760> we<00:16:57.120> can<00:16:57.380> remove<00:16:58.380> Len<00:16:58.709> and 00:16:59.090 --> 00:16:59.100 align:start position:0% which means we can remove Len and 00:16:59.100 --> 00:17:04.730 align:start position:0% which means we can remove Len and replace<00:16:59.579> every<00:17:00.089> Len<00:17:00.300> by<00:17:00.690> length<00:17:01.940> okay<00:17:02.940> and<00:17:03.740> now 00:17:04.730 --> 00:17:04.740 align:start position:0% replace every Len by length okay and now 00:17:04.740 --> 00:17:07.220 align:start position:0% replace every Len by length okay and now we<00:17:04.799> see<00:17:05.189> that<00:17:05.540> inside<00:17:06.540> this<00:17:06.660> if<00:17:06.870> statement 00:17:07.220 --> 00:17:07.230 align:start position:0% we see that inside this if statement 00:17:07.230 --> 00:17:09.679 align:start position:0% we see that inside this if statement inside<00:17:07.709> the<00:17:08.040> loop<00:17:08.220> yeah<00:17:09.089> that's<00:17:09.299> that<00:17:09.390> the 00:17:09.679 --> 00:17:09.689 align:start position:0% inside the loop yeah that's that the 00:17:09.689 --> 00:17:11.539 align:start position:0% inside the loop yeah that's that the point<00:17:10.020> where<00:17:10.199> I<00:17:10.230> could<00:17:10.949> use<00:17:10.980> a<00:17:11.130> laser<00:17:11.309> pointer 00:17:11.539 --> 00:17:11.549 align:start position:0% point where I could use a laser pointer 00:17:11.549 --> 00:17:14.750 align:start position:0% point where I could use a laser pointer but<00:17:11.880> so<00:17:12.870> there<00:17:13.049> is<00:17:13.140> a<00:17:13.169> less<00:17:13.530> than<00:17:13.559> eye<00:17:14.130> length 00:17:14.750 --> 00:17:14.760 align:start position:0% but so there is a less than eye length 00:17:14.760 --> 00:17:17.840 align:start position:0% but so there is a less than eye length so<00:17:15.150> if<00:17:15.360> is<00:17:15.540> 0<00:17:15.839> less<00:17:16.439> than<00:17:16.470> I<00:17:16.919> length<00:17:17.250> revert 00:17:17.840 --> 00:17:17.850 align:start position:0% so if is 0 less than I length revert 00:17:17.850 --> 00:17:19.970 align:start position:0% so if is 0 less than I length revert that<00:17:18.059> is<00:17:18.449> the<00:17:18.540> bounce<00:17:18.750> check<00:17:19.020> we<00:17:19.199> had<00:17:19.380> in<00:17:19.650> the 00:17:19.970 --> 00:17:19.980 align:start position:0% that is the bounce check we had in the 00:17:19.980 --> 00:17:26.299 align:start position:0% that is the bounce check we had in the in<00:17:20.669> the<00:17:20.939> function<00:17:21.870> and<00:17:23.750> we<00:17:24.750> realize<00:17:25.169> that<00:17:25.309> less 00:17:26.299 --> 00:17:26.309 align:start position:0% in the function and we realize that less 00:17:26.309 --> 00:17:27.799 align:start position:0% in the function and we realize that less than<00:17:26.370> eye<00:17:26.850> length<00:17:27.150> is<00:17:27.329> also<00:17:27.569> the<00:17:27.660> loop 00:17:27.799 --> 00:17:27.809 align:start position:0% than eye length is also the loop 00:17:27.809 --> 00:17:29.630 align:start position:0% than eye length is also the loop condition<00:17:28.020> so<00:17:28.380> the<00:17:28.500> for<00:17:28.740> loop<00:17:28.919> has<00:17:29.580> a 00:17:29.630 --> 00:17:29.640 align:start position:0% condition so the for loop has a 00:17:29.640 --> 00:17:32.299 align:start position:0% condition so the for loop has a condition<00:17:30.179> and<00:17:30.510> it<00:17:31.320> runs<00:17:31.470> as<00:17:31.679> long<00:17:31.860> as<00:17:32.010> this<00:17:32.160> is 00:17:32.299 --> 00:17:32.309 align:start position:0% condition and it runs as long as this is 00:17:32.309 --> 00:17:34.220 align:start position:0% condition and it runs as long as this is true<00:17:32.490> so<00:17:32.790> as<00:17:33.030> long<00:17:33.179> as<00:17:33.299> I<00:17:33.419> is<00:17:33.450> Len<00:17:33.750> less<00:17:34.020> than 00:17:34.220 --> 00:17:34.230 align:start position:0% true so as long as I is Len less than 00:17:34.230 --> 00:17:36.710 align:start position:0% true so as long as I is Len less than length<00:17:34.410> the<00:17:35.250> for<00:17:35.460> loop<00:17:35.580> runs<00:17:35.790> and<00:17:36.059> this<00:17:36.450> means 00:17:36.710 --> 00:17:36.720 align:start position:0% length the for loop runs and this means 00:17:36.720 --> 00:17:38.539 align:start position:0% length the for loop runs and this means that<00:17:36.870> inside<00:17:37.320> the<00:17:37.470> loop<00:17:37.620> inside<00:17:38.190> the<00:17:38.280> body<00:17:38.460> of 00:17:38.539 --> 00:17:38.549 align:start position:0% that inside the loop inside the body of 00:17:38.549 --> 00:17:41.240 align:start position:0% that inside the loop inside the body of the<00:17:38.730> for<00:17:38.909> loop<00:17:39.110> less<00:17:40.110> than<00:17:40.350> I<00:17:40.530> length<00:17:40.860> would 00:17:41.240 --> 00:17:41.250 align:start position:0% the for loop less than I length would 00:17:41.250 --> 00:17:42.740 align:start position:0% the for loop less than I length would always<00:17:41.429> be<00:17:41.669> true<00:17:41.850> otherwise<00:17:42.210> the<00:17:42.419> body<00:17:42.570> would 00:17:42.740 --> 00:17:42.750 align:start position:0% always be true otherwise the body would 00:17:42.750 --> 00:17:43.950 align:start position:0% always be true otherwise the body would not<00:17:42.840> execute 00:17:43.950 --> 00:17:43.960 align:start position:0% not execute 00:17:43.960 --> 00:17:47.009 align:start position:0% not execute so<00:17:44.740> this<00:17:45.460> means<00:17:45.639> inside<00:17:45.970> this<00:17:46.210> bounced<00:17:46.629> check 00:17:47.009 --> 00:17:47.019 align:start position:0% so this means inside this bounced check 00:17:47.019 --> 00:17:49.649 align:start position:0% so this means inside this bounced check we<00:17:47.320> can<00:17:47.499> replace<00:17:47.799> less<00:17:48.610> than<00:17:48.820> eye<00:17:48.999> length<00:17:49.269> by 00:17:49.649 --> 00:17:49.659 align:start position:0% we can replace less than eye length by 00:17:49.659 --> 00:17:56.940 align:start position:0% we can replace less than eye length by true<00:17:50.169> or<00:17:50.499> 1<00:17:54.929> okay<00:17:55.929> and<00:17:56.049> now<00:17:56.139> we<00:17:56.200> see<00:17:56.440> we<00:17:56.769> have<00:17:56.799> a 00:17:56.940 --> 00:17:56.950 align:start position:0% true or 1 okay and now we see we have a 00:17:56.950 --> 00:17:59.430 align:start position:0% true or 1 okay and now we see we have a constant<00:17:57.549> there<00:17:57.789> and<00:17:58.090> apply<00:17:58.749> an<00:17:58.809> operation<00:17:59.320> on 00:17:59.430 --> 00:17:59.440 align:start position:0% constant there and apply an operation on 00:17:59.440 --> 00:18:02.700 align:start position:0% constant there and apply an operation on that<00:17:59.470> is<00:17:59.769> zero<00:18:00.129> is<00:18:00.369> zero<00:18:00.669> is<00:18:00.850> the<00:18:01.029> is<00:18:01.869> EVM<00:18:02.379> speak 00:18:02.700 --> 00:18:02.710 align:start position:0% that is zero is zero is the is EVM speak 00:18:02.710 --> 00:18:07.169 align:start position:0% that is zero is zero is the is EVM speak for<00:18:03.840> logical<00:18:04.840> negation<00:18:05.110> so<00:18:05.830> is<00:18:06.159> zero<00:18:06.610> of<00:18:06.730> one 00:18:07.169 --> 00:18:07.179 align:start position:0% for logical negation so is zero of one 00:18:07.179 --> 00:18:09.840 align:start position:0% for logical negation so is zero of one so<00:18:07.720> it's<00:18:07.929> zero<00:18:08.230> it's<00:18:08.619> basically<00:18:08.889> not<00:18:09.129> true 00:18:09.840 --> 00:18:09.850 align:start position:0% so it's zero it's basically not true 00:18:09.850 --> 00:18:12.600 align:start position:0% so it's zero it's basically not true which<00:18:10.269> is<00:18:10.419> false<00:18:10.840> which<00:18:11.139> is<00:18:11.289> zero<00:18:11.710> so<00:18:12.399> we<00:18:12.429> can 00:18:12.600 --> 00:18:12.610 align:start position:0% which is false which is zero so we can 00:18:12.610 --> 00:18:15.919 align:start position:0% which is false which is zero so we can replace<00:18:12.759> if<00:18:13.119> it's<00:18:13.419> zero<00:18:13.690> of<00:18:13.899> 1<00:18:14.110> by<00:18:14.320> if<00:18:14.529> zero<00:18:15.039> and 00:18:15.919 --> 00:18:15.929 align:start position:0% replace if it's zero of 1 by if zero and 00:18:15.929 --> 00:18:18.269 align:start position:0% replace if it's zero of 1 by if zero and now<00:18:16.929> we<00:18:16.960> see<00:18:17.259> so<00:18:17.440> you<00:18:17.499> see<00:18:17.710> these<00:18:17.830> are<00:18:18.009> really 00:18:18.269 --> 00:18:18.279 align:start position:0% now we see so you see these are really 00:18:18.279 --> 00:18:21.149 align:start position:0% now we see so you see these are really tiny<00:18:18.869> modifications<00:18:19.869> we<00:18:20.529> could<00:18:20.830> have<00:18:20.919> removed 00:18:21.149 --> 00:18:21.159 align:start position:0% tiny modifications we could have removed 00:18:21.159 --> 00:18:23.039 align:start position:0% tiny modifications we could have removed the<00:18:21.340> if<00:18:21.460> altogether<00:18:21.909> or<00:18:22.240> for<00:18:22.690> a<00:18:22.720> long<00:18:22.869> time 00:18:23.039 --> 00:18:23.049 align:start position:0% the if altogether or for a long time 00:18:23.049 --> 00:18:26.039 align:start position:0% the if altogether or for a long time already<00:18:23.200> but<00:18:23.559> we<00:18:24.490> want<00:18:24.639> to<00:18:24.730> keep<00:18:24.850> every<00:18:25.179> step 00:18:26.039 --> 00:18:26.049 align:start position:0% already but we want to keep every step 00:18:26.049 --> 00:18:28.889 align:start position:0% already but we want to keep every step as<00:18:26.980> small<00:18:27.309> as<00:18:27.429> possible<00:18:27.580> so<00:18:27.999> we<00:18:28.360> see<00:18:28.480> if<00:18:28.629> zero 00:18:28.889 --> 00:18:28.899 align:start position:0% as small as possible so we see if zero 00:18:28.899 --> 00:18:31.230 align:start position:0% as small as possible so we see if zero and<00:18:29.289> of<00:18:29.559> course<00:18:29.799> yeah<00:18:30.369> it's<00:18:30.700> a<00:18:30.820> condition<00:18:31.210> that 00:18:31.230 --> 00:18:31.240 align:start position:0% and of course yeah it's a condition that 00:18:31.240 --> 00:18:32.730 align:start position:0% and of course yeah it's a condition that is<00:18:31.360> always<00:18:31.659> false<00:18:31.899> so<00:18:32.200> the<00:18:32.379> whole<00:18:32.529> if 00:18:32.730 --> 00:18:32.740 align:start position:0% is always false so the whole if 00:18:32.740 --> 00:18:35.879 align:start position:0% is always false so the whole if statement<00:18:33.399> can<00:18:33.519> be<00:18:33.549> removed<00:18:34.289> cool<00:18:35.289> that<00:18:35.559> so 00:18:35.879 --> 00:18:35.889 align:start position:0% statement can be removed cool that so 00:18:35.889 --> 00:18:37.889 align:start position:0% statement can be removed cool that so and<00:18:36.129> that<00:18:36.369> was<00:18:36.580> did<00:18:37.509> you<00:18:37.570> see<00:18:37.690> the<00:18:37.779> magic 00:18:37.889 --> 00:18:37.899 align:start position:0% and that was did you see the magic 00:18:37.899 --> 00:18:39.180 align:start position:0% and that was did you see the magic happening<00:18:38.320> this<00:18:38.619> is<00:18:38.769> where<00:18:38.919> the<00:18:39.009> balance 00:18:39.180 --> 00:18:39.190 align:start position:0% happening this is where the balance 00:18:39.190 --> 00:18:44.009 align:start position:0% happening this is where the balance check<00:18:39.899> was<00:18:40.899> removed<00:18:41.259> and<00:18:41.759> now<00:18:42.759> we<00:18:42.820> can<00:18:43.149> do<00:18:43.419> some 00:18:44.009 --> 00:18:44.019 align:start position:0% check was removed and now we can do some 00:18:44.019 --> 00:18:46.950 align:start position:0% check was removed and now we can do some more<00:18:44.230> things<00:18:44.499> we<00:18:45.309> again<00:18:45.669> explode<00:18:46.539> this 00:18:46.950 --> 00:18:46.960 align:start position:0% more things we again explode this 00:18:46.960 --> 00:18:49.200 align:start position:0% more things we again explode this complex<00:18:47.559> expression<00:18:48.100> into<00:18:48.429> multiple 00:18:49.200 --> 00:18:49.210 align:start position:0% complex expression into multiple 00:18:49.210 --> 00:18:52.799 align:start position:0% complex expression into multiple assignments<00:18:49.659> two<00:18:49.779> new<00:18:49.929> variables<00:18:50.080> and<00:18:51.809> ok 00:18:52.799 --> 00:18:52.809 align:start position:0% assignments two new variables and ok 00:18:52.809 --> 00:18:55.259 align:start position:0% assignments two new variables and ok this<00:18:52.960> is<00:18:53.139> this<00:18:53.889> is<00:18:54.009> I<00:18:54.070> think<00:18:54.100> the<00:18:54.369> most<00:18:54.610> tricky 00:18:55.259 --> 00:18:55.269 align:start position:0% this is this is I think the most tricky 00:18:55.269 --> 00:18:58.619 align:start position:0% this is this is I think the most tricky transformation<00:18:56.970> if<00:18:57.970> you<00:18:58.119> take<00:18:58.269> a<00:18:58.299> look<00:18:58.480> at 00:18:58.619 --> 00:18:58.629 align:start position:0% transformation if you take a look at 00:18:58.629 --> 00:19:04.230 align:start position:0% transformation if you take a look at underscore<00:18:59.139> 2<00:18:59.700> it<00:19:00.700> is<00:19:00.999> I<00:19:02.730> multiplied<00:19:03.730> by<00:19:04.029> hex 00:19:04.230 --> 00:19:04.240 align:start position:0% underscore 2 it is I multiplied by hex 00:19:04.240 --> 00:19:08.129 align:start position:0% underscore 2 it is I multiplied by hex 20<00:19:04.629> or<00:19:04.899> by<00:19:05.049> x2<00:19:05.350> 0<00:19:05.559> and<00:19:06.190> I<00:19:07.149> is<00:19:07.210> the<00:19:07.659> loop 00:19:08.129 --> 00:19:08.139 align:start position:0% 20 or by x2 0 and I is the loop 00:19:08.139 --> 00:19:11.509 align:start position:0% 20 or by x2 0 and I is the loop iteration<00:19:08.769> counter<00:19:09.899> so<00:19:10.899> this<00:19:11.049> means 00:19:11.509 --> 00:19:11.519 align:start position:0% iteration counter so this means 00:19:11.519 --> 00:19:15.419 align:start position:0% iteration counter so this means underscore<00:19:12.519> 2<00:19:12.730> is<00:19:12.879> always<00:19:13.330> 0<00:19:14.019> X<00:19:14.200> 20<00:19:14.679> times<00:19:15.129> the 00:19:15.419 --> 00:19:15.429 align:start position:0% underscore 2 is always 0 X 20 times the 00:19:15.429 --> 00:19:17.820 align:start position:0% underscore 2 is always 0 X 20 times the number<00:19:15.669> of<00:19:15.759> iterations<00:19:16.299> and<00:19:16.529> we<00:19:17.529> know<00:19:17.649> that 00:19:17.820 --> 00:19:17.830 align:start position:0% number of iterations and we know that 00:19:17.830 --> 00:19:19.200 align:start position:0% number of iterations and we know that multiplication<00:19:18.220> is<00:19:18.549> more<00:19:18.759> expensive<00:19:19.029> than 00:19:19.200 --> 00:19:19.210 align:start position:0% multiplication is more expensive than 00:19:19.210 --> 00:19:23.759 align:start position:0% multiplication is more expensive than addition<00:19:19.559> but<00:19:20.820> as<00:19:21.820> the<00:19:22.059> code<00:19:22.210> is<00:19:22.539> here<00:19:23.169> now<00:19:23.379> we 00:19:23.759 --> 00:19:23.769 align:start position:0% addition but as the code is here now we 00:19:23.769 --> 00:19:27.149 align:start position:0% addition but as the code is here now we multiply<00:19:24.809> in<00:19:25.809> every<00:19:26.110> loop<00:19:26.289> iteration<00:19:26.889> anyway 00:19:27.149 --> 00:19:27.159 align:start position:0% multiply in every loop iteration anyway 00:19:27.159 --> 00:19:28.680 align:start position:0% multiply in every loop iteration anyway so<00:19:27.220> we<00:19:27.340> would<00:19:27.460> like<00:19:27.610> to<00:19:27.669> replace<00:19:28.210> the<00:19:28.480> vinyl 00:19:28.680 --> 00:19:28.690 align:start position:0% so we would like to replace the vinyl 00:19:28.690 --> 00:19:32.399 align:start position:0% so we would like to replace the vinyl edition<00:19:28.960> and<00:19:30.360> so<00:19:31.360> what<00:19:31.509> we<00:19:31.629> can<00:19:31.779> so<00:19:32.019> and<00:19:32.320> we 00:19:32.399 --> 00:19:32.409 align:start position:0% edition and so what we can so and we 00:19:32.409 --> 00:19:35.669 align:start position:0% edition and so what we can so and we know<00:19:32.610> underscore<00:19:33.610> 2<00:19:33.789> is<00:19:33.970> 0<00:19:34.570> X<00:19:34.720> 20<00:19:34.990> times<00:19:35.259> number 00:19:35.669 --> 00:19:35.679 align:start position:0% know underscore 2 is 0 X 20 times number 00:19:35.679 --> 00:19:38.549 align:start position:0% know underscore 2 is 0 X 20 times number of<00:19:35.740> iterations<00:19:36.190> so<00:19:36.450> we<00:19:37.450> can<00:19:37.690> write<00:19:38.320> in<00:19:38.470> a 00:19:38.549 --> 00:19:38.559 align:start position:0% of iterations so we can write in a 00:19:38.559 --> 00:19:41.039 align:start position:0% of iterations so we can write in a different<00:19:38.590> way<00:19:39.129> where<00:19:39.490> we<00:19:39.700> just<00:19:39.999> add<00:19:40.210> up<00:19:40.659> in 00:19:41.039 --> 00:19:41.049 align:start position:0% different way where we just add up in 00:19:41.049 --> 00:19:43.739 align:start position:0% different way where we just add up in every<00:19:41.619> iteration<00:19:41.860> and<00:19:42.369> it<00:19:42.700> will<00:19:42.879> it's<00:19:43.570> a<00:19:43.629> bit 00:19:43.739 --> 00:19:43.749 align:start position:0% every iteration and it will it's a bit 00:19:43.749 --> 00:19:46.200 align:start position:0% every iteration and it will it's a bit tricky<00:19:43.960> to<00:19:43.990> find<00:19:44.289> the<00:19:44.409> correct<00:19:44.619> start<00:19:45.009> so<00:19:45.580> we 00:19:46.200 --> 00:19:46.210 align:start position:0% tricky to find the correct start so we 00:19:46.210 --> 00:19:48.149 align:start position:0% tricky to find the correct start so we pull<00:19:46.480> out<00:19:46.629> this<00:19:46.840> under<00:19:47.139> code<00:19:47.350> underscore<00:19:47.950> 2 00:19:48.149 --> 00:19:48.159 align:start position:0% pull out this under code underscore 2 00:19:48.159 --> 00:19:49.980 align:start position:0% pull out this under code underscore 2 outside<00:19:48.970> of<00:19:49.090> the<00:19:49.179> loop<00:19:49.330> and<00:19:49.480> store<00:19:49.690> we<00:19:49.840> have<00:19:49.960> to 00:19:49.980 --> 00:19:49.990 align:start position:0% outside of the loop and store we have to 00:19:49.990 --> 00:19:52.340 align:start position:0% outside of the loop and store we have to start<00:19:50.200> with<00:19:50.320> minus<00:19:50.740> 0<00:19:50.950> X<00:19:51.100> 20 00:19:52.340 --> 00:19:52.350 align:start position:0% start with minus 0 X 20 00:19:52.350 --> 00:19:54.710 align:start position:0% start with minus 0 X 20 and<00:19:52.820> then<00:19:53.820> we<00:19:54.120> can<00:19:54.270> replace<00:19:54.419> the 00:19:54.710 --> 00:19:54.720 align:start position:0% and then we can replace the 00:19:54.720 --> 00:19:57.110 align:start position:0% and then we can replace the multiplication<00:19:55.380> by<00:19:55.500> an<00:19:55.590> addition<00:19:55.890> so<00:19:56.070> 2<00:19:56.429> is<00:19:56.669> 2 00:19:57.110 --> 00:19:57.120 align:start position:0% multiplication by an addition so 2 is 2 00:19:57.120 --> 00:20:04.760 align:start position:0% multiplication by an addition so 2 is 2 plus<00:19:57.150> 0<00:19:57.840> X<00:19:57.900> 20<00:20:00.620> ok<00:20:03.080> yeah<00:20:04.080> if<00:20:04.500> you<00:20:04.590> look<00:20:04.710> at 00:20:04.760 --> 00:20:04.770 align:start position:0% plus 0 X 20 ok yeah if you look at 00:20:04.770 --> 00:20:06.590 align:start position:0% plus 0 X 20 ok yeah if you look at underscore<00:20:05.160> 3<00:20:05.370> that's<00:20:05.640> just<00:20:06.030> underscore<00:20:06.450> 2 00:20:06.590 --> 00:20:06.600 align:start position:0% underscore 3 that's just underscore 2 00:20:06.600 --> 00:20:10.010 align:start position:0% underscore 3 that's just underscore 2 plus<00:20:07.020> data<00:20:07.669> so<00:20:08.669> this<00:20:09.059> is<00:20:09.210> kind<00:20:09.600> of<00:20:09.720> a<00:20:09.809> similar 00:20:10.010 --> 00:20:10.020 align:start position:0% plus data so this is kind of a similar 00:20:10.020 --> 00:20:14.000 align:start position:0% plus data so this is kind of a similar variable<00:20:10.650> or<00:20:11.520> in<00:20:12.419> other<00:20:12.600> words<00:20:12.840> these<00:20:13.710> are<00:20:13.890> all 00:20:14.000 --> 00:20:14.010 align:start position:0% variable or in other words these are all 00:20:14.010 --> 00:20:15.919 align:start position:0% variable or in other words these are all additions<00:20:14.520> so<00:20:14.940> they<00:20:15.090> are<00:20:15.210> all<00:20:15.360> associative 00:20:15.919 --> 00:20:15.929 align:start position:0% additions so they are all associative 00:20:15.929 --> 00:20:18.049 align:start position:0% additions so they are all associative which<00:20:16.230> means<00:20:16.470> we<00:20:16.710> can<00:20:16.860> pull<00:20:17.130> out<00:20:17.280> the<00:20:17.549> data<00:20:17.730> to 00:20:18.049 --> 00:20:18.059 align:start position:0% which means we can pull out the data to 00:20:18.059 --> 00:20:24.200 align:start position:0% which means we can pull out the data to the<00:20:18.090> very<00:20:18.390> beginning<00:20:21.320> yeah<00:20:22.490> so<00:20:23.490> underscore<00:20:24.030> 2 00:20:24.200 --> 00:20:24.210 align:start position:0% the very beginning yeah so underscore 2 00:20:24.210 --> 00:20:26.870 align:start position:0% the very beginning yeah so underscore 2 is<00:20:24.450> so<00:20:24.900> we<00:20:25.020> know<00:20:25.409> the<00:20:25.559> data<00:20:25.710> is<00:20:25.980> added<00:20:26.280> to<00:20:26.490> 2<00:20:26.730> at 00:20:26.870 --> 00:20:26.880 align:start position:0% is so we know the data is added to 2 at 00:20:26.880 --> 00:20:28.430 align:start position:0% is so we know the data is added to 2 at the<00:20:27.000> very<00:20:27.150> beginning<00:20:27.570> and<00:20:27.750> not<00:20:27.960> anymore 00:20:28.430 --> 00:20:28.440 align:start position:0% the very beginning and not anymore 00:20:28.440 --> 00:20:33.529 align:start position:0% the very beginning and not anymore inside<00:20:28.950> the<00:20:29.100> loop<00:20:29.870> ok<00:20:31.400> and<00:20:32.400> I<00:20:33.210> think<00:20:33.390> that's 00:20:33.529 --> 00:20:33.539 align:start position:0% inside the loop ok and I think that's 00:20:33.539 --> 00:20:35.690 align:start position:0% inside the loop ok and I think that's almost<00:20:34.350> it<00:20:34.559> already<00:20:34.770> yeah<00:20:35.010> ok<00:20:35.250> another<00:20:35.549> thing 00:20:35.690 --> 00:20:35.700 align:start position:0% almost it already yeah ok another thing 00:20:35.700 --> 00:20:38.659 align:start position:0% almost it already yeah ok another thing we<00:20:35.909> can<00:20:36.030> do<00:20:36.179> is<00:20:36.950> if<00:20:37.950> you<00:20:38.039> look<00:20:38.190> at<00:20:38.309> the 00:20:38.659 --> 00:20:38.669 align:start position:0% we can do is if you look at the 00:20:38.669 --> 00:20:42.380 align:start position:0% we can do is if you look at the definition<00:20:38.820> of<00:20:39.150> underscore<00:20:39.510> 2<00:20:39.690> now<00:20:40.970> and<00:20:41.970> if 00:20:42.380 --> 00:20:42.390 align:start position:0% definition of underscore 2 now and if 00:20:42.390 --> 00:20:44.899 align:start position:0% definition of underscore 2 now and if you<00:20:42.600> insert<00:20:43.110> data<00:20:43.650> into<00:20:43.890> that<00:20:44.340> then<00:20:44.549> you<00:20:44.669> see 00:20:44.899 --> 00:20:44.909 align:start position:0% you insert data into that then you see 00:20:44.909 --> 00:20:53.060 align:start position:0% you insert data into that then you see this<00:20:45.210> is<00:20:45.390> x<00:20:46.049> +<00:20:46.620> 0<00:20:47.159> x<00:20:47.309> 20<00:20:47.700> -<00:20:48.330> 0<00:20:48.600> x<00:20:48.720> 20<00:20:51.440> so<00:20:52.440> we<00:20:52.770> can 00:20:53.060 --> 00:20:53.070 align:start position:0% this is x + 0 x 20 - 0 x 20 so we can 00:20:53.070 --> 00:20:58.100 align:start position:0% this is x + 0 x 20 - 0 x 20 so we can replace<00:20:53.929> underscore<00:20:54.929> 2<00:20:55.110> by<00:20:55.320> data<00:20:55.679> I<00:20:56.780> know<00:20:57.780> by<00:20:57.929> X 00:20:58.100 --> 00:20:58.110 align:start position:0% replace underscore 2 by data I know by X 00:20:58.110 --> 00:21:01.549 align:start position:0% replace underscore 2 by data I know by X of<00:20:58.260> course<00:20:58.470> yeah<00:20:58.650> so<00:20:58.830> it<00:20:58.919> was<00:20:59.039> x<00:20:59.309> +<00:20:59.610> 0<00:20:59.640> X<00:20:59.970> 2<00:21:00.659> 0<00:21:00.690> -<00:21:01.440> 3 00:21:01.549 --> 00:21:01.559 align:start position:0% of course yeah so it was x + 0 X 2 0 - 3 00:21:01.559 --> 00:21:05.870 align:start position:0% of course yeah so it was x + 0 X 2 0 - 3 X<00:21:01.740> -<00:21:01.799> 0<00:21:01.919> so<00:21:02.250> it's<00:21:02.370> X<00:21:02.720> and<00:21:04.190> we<00:21:05.190> also<00:21:05.340> see<00:21:05.549> that<00:21:05.580> X 00:21:05.870 --> 00:21:05.880 align:start position:0% X - 0 so it's X and we also see that X 00:21:05.880 --> 00:21:09.320 align:start position:0% X - 0 so it's X and we also see that X is<00:21:06.059> unused<00:21:06.720> in<00:21:07.169> the<00:21:07.380> rest<00:21:07.530> of<00:21:07.710> the<00:21:07.830> program<00:21:08.330> so 00:21:09.320 --> 00:21:09.330 align:start position:0% is unused in the rest of the program so 00:21:09.330 --> 00:21:13.399 align:start position:0% is unused in the rest of the program so we<00:21:09.450> can<00:21:09.630> replace<00:21:10.169> underscore<00:21:11.100> 2<00:21:11.280> by<00:21:11.520> X<00:21:12.409> now 00:21:13.399 --> 00:21:13.409 align:start position:0% we can replace underscore 2 by X now 00:21:13.409 --> 00:21:16.430 align:start position:0% we can replace underscore 2 by X now that<00:21:13.860> was<00:21:14.010> the<00:21:14.130> next<00:21:14.309> step<00:21:14.929> we<00:21:15.929> see<00:21:16.110> that<00:21:16.230> data 00:21:16.430 --> 00:21:16.440 align:start position:0% that was the next step we see that data 00:21:16.440 --> 00:21:18.020 align:start position:0% that was the next step we see that data is<00:21:16.679> fully<00:21:16.950> unused<00:21:17.370> in<00:21:17.610> the<00:21:17.700> rest<00:21:17.850> of<00:21:17.970> the 00:21:18.020 --> 00:21:18.030 align:start position:0% is fully unused in the rest of the 00:21:18.030 --> 00:21:19.130 align:start position:0% is fully unused in the rest of the program<00:21:18.299> so<00:21:18.419> we<00:21:18.450> can<00:21:18.659> remove<00:21:18.870> it<00:21:19.020> altogether 00:21:19.130 --> 00:21:19.140 align:start position:0% program so we can remove it altogether 00:21:19.140 --> 00:21:20.659 align:start position:0% program so we can remove it altogether yeah 00:21:20.659 --> 00:21:20.669 align:start position:0% yeah 00:21:20.669 --> 00:21:23.270 align:start position:0% yeah and<00:21:21.090> X<00:21:21.419> is<00:21:21.600> not<00:21:21.630> used<00:21:21.960> anymore<00:21:22.080> so<00:21:22.740> there's<00:21:22.980> no 00:21:23.270 --> 00:21:23.280 align:start position:0% and X is not used anymore so there's no 00:21:23.280 --> 00:21:26.570 align:start position:0% and X is not used anymore so there's no need<00:21:23.909> to<00:21:24.150> redefine<00:21:24.750> it<00:21:25.200> as<00:21:25.500> underscore<00:21:26.220> 2<00:21:26.370> so 00:21:26.570 --> 00:21:26.580 align:start position:0% need to redefine it as underscore 2 so 00:21:26.580 --> 00:21:29.870 align:start position:0% need to redefine it as underscore 2 so we<00:21:26.700> can<00:21:26.820> replace<00:21:26.970> underscore<00:21:27.450> 2<00:21:27.600> by<00:21:27.750> X<00:21:28.880> ok 00:21:29.870 --> 00:21:29.880 align:start position:0% we can replace underscore 2 by X ok 00:21:29.880 --> 00:21:33.649 align:start position:0% we can replace underscore 2 by X ok that's<00:21:30.330> almost<00:21:30.720> it<00:21:30.960> I<00:21:31.080> think<00:21:31.760> yeah<00:21:32.789> underscore 00:21:33.649 --> 00:21:33.659 align:start position:0% that's almost it I think yeah underscore 00:21:33.659 --> 00:21:36.169 align:start position:0% that's almost it I think yeah underscore one<00:21:33.900> is<00:21:34.260> only<00:21:34.440> used<00:21:34.710> one<00:21:34.980> so<00:21:35.280> we<00:21:35.429> can<00:21:35.580> inline<00:21:36.000> it 00:21:36.169 --> 00:21:36.179 align:start position:0% one is only used one so we can inline it 00:21:36.179 --> 00:21:39.980 align:start position:0% one is only used one so we can inline it back<00:21:36.419> into<00:21:36.600> the<00:21:36.780> expression<00:21:37.080> and<00:21:38.960> yeah<00:21:39.960> I 00:21:39.980 --> 00:21:39.990 align:start position:0% back into the expression and yeah I 00:21:39.990 --> 00:21:42.200 align:start position:0% back into the expression and yeah I would<00:21:40.380> claim<00:21:40.770> that<00:21:41.220> this<00:21:41.400> is<00:21:41.549> the<00:21:41.700> optimal 00:21:42.200 --> 00:21:42.210 align:start position:0% would claim that this is the optimal 00:21:42.210 --> 00:21:44.930 align:start position:0% would claim that this is the optimal program<00:21:42.960> the<00:21:43.679> only<00:21:43.710> thing<00:21:44.130> is<00:21:44.280> that<00:21:44.490> one 00:21:44.930 --> 00:21:44.940 align:start position:0% program the only thing is that one 00:21:44.940 --> 00:21:50.149 align:start position:0% program the only thing is that one already<00:21:45.539> mentioned<00:21:46.020> we<00:21:46.289> might<00:21:48.860> replace<00:21:49.860> the 00:21:50.149 --> 00:21:50.159 align:start position:0% already mentioned we might replace the 00:21:50.159 --> 00:21:54.470 align:start position:0% already mentioned we might replace the loop<00:21:51.030> iteration<00:21:51.600> variable<00:21:52.169> by<00:21:52.620> X<00:21:52.919> and<00:21:53.220> add<00:21:53.460> 0<00:21:54.240> X 00:21:54.470 --> 00:21:54.480 align:start position:0% loop iteration variable by X and add 0 X 00:21:54.480 --> 00:21:58.899 align:start position:0% loop iteration variable by X and add 0 X 20<00:21:55.380> instead<00:21:55.740> of<00:21:55.830> 1<00:21:56.039> for<00:21:56.280> each<00:21:56.309> iteration<00:21:56.900> but 00:21:58.899 --> 00:21:58.909 align:start position:0% 20 instead of 1 for each iteration but 00:21:58.909 --> 00:22:01.700 align:start position:0% 20 instead of 1 for each iteration but yeah<00:21:59.909> if<00:22:00.750> you<00:22:00.960> do<00:22:01.049> that<00:22:01.230> then<00:22:01.380> we<00:22:01.470> would<00:22:01.620> have 00:22:01.700 --> 00:22:01.710 align:start position:0% yeah if you do that then we would have 00:22:01.710 --> 00:22:03.020 align:start position:0% yeah if you do that then we would have to<00:22:01.799> modify<00:22:02.070> length<00:22:02.400> we<00:22:02.700> would<00:22:02.820> have<00:22:02.940> to 00:22:03.020 --> 00:22:03.030 align:start position:0% to modify length we would have to 00:22:03.030 --> 00:22:05.870 align:start position:0% to modify length we would have to compare<00:22:03.360> against<00:22:03.780> length<00:22:04.049> x<00:22:04.470> 0<00:22:04.890> X<00:22:05.040> 20 00:22:05.870 --> 00:22:05.880 align:start position:0% compare against length x 0 X 20 00:22:05.880 --> 00:22:08.270 align:start position:0% compare against length x 0 X 20 and<00:22:05.970> I<00:22:06.510> think<00:22:06.570> that<00:22:06.900> can<00:22:07.290> create<00:22:08.190> problems 00:22:08.270 --> 00:22:08.280 align:start position:0% and I think that can create problems 00:22:08.280 --> 00:22:14.000 align:start position:0% and I think that can create problems with<00:22:09.030> overflow<00:22:11.750> okay<00:22:12.750> that<00:22:13.380> was<00:22:13.530> an<00:22:13.680> example 00:22:14.000 --> 00:22:14.010 align:start position:0% with overflow okay that was an example 00:22:14.010 --> 00:22:16.850 align:start position:0% with overflow okay that was an example of<00:22:14.250> how<00:22:14.550> the<00:22:14.610> optimizer<00:22:15.150> operates<00:22:16.110> you<00:22:16.680> see 00:22:16.850 --> 00:22:16.860 align:start position:0% of how the optimizer operates you see 00:22:16.860 --> 00:22:18.890 align:start position:0% of how the optimizer operates you see that<00:22:17.010> the<00:22:17.100> resulting<00:22:17.490> program<00:22:17.790> is<00:22:17.910> really 00:22:18.890 --> 00:22:18.900 align:start position:0% that the resulting program is really 00:22:18.900 --> 00:22:21.620 align:start position:0% that the resulting program is really short<00:22:19.200> and<00:22:19.470> all<00:22:20.340> the<00:22:20.940> intermediate<00:22:21.210> steps 00:22:21.620 --> 00:22:21.630 align:start position:0% short and all the intermediate steps 00:22:21.630 --> 00:22:24.920 align:start position:0% short and all the intermediate steps were<00:22:22.370> quite<00:22:23.370> small 00:22:24.920 --> 00:22:24.930 align:start position:0% were quite small 00:22:24.930 --> 00:22:28.340 align:start position:0% were quite small another<00:22:25.830> thing<00:22:26.130> we<00:22:26.310> plan<00:22:26.640> to<00:22:26.880> do<00:22:27.030> is<00:22:27.350> memory 00:22:28.340 --> 00:22:28.350 align:start position:0% another thing we plan to do is memory 00:22:28.350 --> 00:22:32.060 align:start position:0% another thing we plan to do is memory optimizations<00:22:30.470> currently<00:22:31.470> solidity<00:22:31.830> does 00:22:32.060 --> 00:22:32.070 align:start position:0% optimizations currently solidity does 00:22:32.070 --> 00:22:33.710 align:start position:0% optimizations currently solidity does not<00:22:32.250> have<00:22:32.400> any<00:22:32.610> memory<00:22:32.880> management<00:22:33.210> because 00:22:33.710 --> 00:22:33.720 align:start position:0% not have any memory management because 00:22:33.720 --> 00:22:35.720 align:start position:0% not have any memory management because in<00:22:34.080> the<00:22:34.290> EVM<00:22:34.620> memory<00:22:34.950> is<00:22:35.070> usually<00:22:35.190> short-lived 00:22:35.720 --> 00:22:35.730 align:start position:0% in the EVM memory is usually short-lived 00:22:35.730 --> 00:22:38.000 align:start position:0% in the EVM memory is usually short-lived so<00:22:36.120> it<00:22:36.210> doesn't<00:22:36.540> make<00:22:37.080> sense<00:22:37.350> to<00:22:37.500> have<00:22:37.530> to<00:22:37.890> add 00:22:38.000 --> 00:22:38.010 align:start position:0% so it doesn't make sense to have to add 00:22:38.010 --> 00:22:40.760 align:start position:0% so it doesn't make sense to have to add the<00:22:38.220> huge<00:22:38.700> overhead<00:22:39.360> of<00:22:39.510> memory<00:22:39.810> management 00:22:40.760 --> 00:22:40.770 align:start position:0% the huge overhead of memory management 00:22:40.770 --> 00:22:43.610 align:start position:0% the huge overhead of memory management and<00:22:41.160> these<00:22:41.970> currently<00:22:42.510> results<00:22:43.020> in<00:22:43.230> some 00:22:43.610 --> 00:22:43.620 align:start position:0% and these currently results in some 00:22:43.620 --> 00:22:46.190 align:start position:0% and these currently results in some wasted<00:22:44.130> memory<00:22:44.510> especially<00:22:45.510> if<00:22:45.660> you<00:22:45.900> for 00:22:46.190 --> 00:22:46.200 align:start position:0% wasted memory especially if you for 00:22:46.200 --> 00:22:49.340 align:start position:0% wasted memory especially if you for example<00:22:46.230> if<00:22:46.560> you<00:22:46.650> allocate<00:22:47.070> a<00:22:48.020> memory<00:22:49.020> array 00:22:49.340 --> 00:22:49.350 align:start position:0% example if you allocate a memory array 00:22:49.350 --> 00:22:52.130 align:start position:0% example if you allocate a memory array inside<00:22:49.830> a<00:22:49.890> function<00:22:50.130> and<00:22:50.700> do<00:22:51.330> not<00:22:51.510> return<00:22:51.750> it 00:22:52.130 --> 00:22:52.140 align:start position:0% inside a function and do not return it 00:22:52.140 --> 00:22:53.630 align:start position:0% inside a function and do not return it so<00:22:52.260> you<00:22:52.320> basically<00:22:52.590> don't<00:22:52.800> really<00:22:53.430> use<00:22:53.610> it 00:22:53.630 --> 00:22:53.640 align:start position:0% so you basically don't really use it 00:22:53.640 --> 00:22:55.610 align:start position:0% so you basically don't really use it then<00:22:54.000> it<00:22:54.330> would<00:22:54.510> make<00:22:54.690> sense<00:22:54.900> to<00:22:55.020> free<00:22:55.410> the 00:22:55.610 --> 00:22:55.620 align:start position:0% then it would make sense to free the 00:22:55.620 --> 00:22:57.320 align:start position:0% then it would make sense to free the memory<00:22:55.770> again<00:22:56.190> after<00:22:56.910> the<00:22:57.000> end<00:22:57.120> of<00:22:57.240> the 00:22:57.320 --> 00:22:57.330 align:start position:0% memory again after the end of the 00:22:57.330 --> 00:23:00.170 align:start position:0% memory again after the end of the function<00:22:57.480> and<00:22:58.460> this<00:22:59.460> is<00:22:59.640> something<00:22:59.820> we 00:23:00.170 --> 00:23:00.180 align:start position:0% function and this is something we 00:23:00.180 --> 00:23:01.970 align:start position:0% function and this is something we believe<00:23:00.450> that<00:23:00.720> the<00:23:00.960> yule<00:23:01.110> optimizer<00:23:01.590> can<00:23:01.830> do 00:23:01.970 --> 00:23:01.980 align:start position:0% believe that the yule optimizer can do 00:23:01.980 --> 00:23:06.220 align:start position:0% believe that the yule optimizer can do when<00:23:02.250> we<00:23:02.370> introduce<00:23:02.820> yes<00:23:03.510> memory<00:23:04.410> objects<00:23:04.980> as 00:23:06.220 --> 00:23:06.230 align:start position:0% when we introduce yes memory objects as 00:23:06.230 --> 00:23:11.500 align:start position:0% when we introduce yes memory objects as yeah<00:23:07.230> first-class<00:23:07.620> citizens<00:23:10.250> there<00:23:11.250> is<00:23:11.400> a 00:23:11.500 --> 00:23:11.510 align:start position:0% yeah first-class citizens there is a 00:23:11.510 --> 00:23:14.270 align:start position:0% yeah first-class citizens there is a version<00:23:12.510> of<00:23:12.690> you<00:23:12.810> that<00:23:13.080> has<00:23:13.200> types<00:23:13.530> and<00:23:13.860> this 00:23:14.270 --> 00:23:14.280 align:start position:0% version of you that has types and this 00:23:14.280 --> 00:23:16.540 align:start position:0% version of you that has types and this would<00:23:14.520> fit<00:23:14.760> nicely<00:23:15.330> into<00:23:15.660> the<00:23:15.870> type<00:23:16.050> Kuehl 00:23:16.540 --> 00:23:16.550 align:start position:0% would fit nicely into the type Kuehl 00:23:16.550 --> 00:23:23.390 align:start position:0% would fit nicely into the type Kuehl dialect<00:23:18.680> yeah<00:23:19.680> so<00:23:20.060> as<00:23:21.060> a<00:23:21.930> summary<00:23:22.260> I<00:23:22.890> hope<00:23:23.220> that 00:23:23.390 --> 00:23:23.400 align:start position:0% dialect yeah so as a summary I hope that 00:23:23.400 --> 00:23:25.100 align:start position:0% dialect yeah so as a summary I hope that the<00:23:23.490> new<00:23:23.640> optimizer<00:23:24.090> will<00:23:24.330> be<00:23:24.420> safer<00:23:24.810> more 00:23:25.100 --> 00:23:25.110 align:start position:0% the new optimizer will be safer more 00:23:25.110 --> 00:23:26.840 align:start position:0% the new optimizer will be safer more transparent<00:23:25.590> and<00:23:25.620> more<00:23:25.710> powerful<00:23:26.250> the<00:23:26.610> main 00:23:26.840 --> 00:23:26.850 align:start position:0% transparent and more powerful the main 00:23:26.850 --> 00:23:28.160 align:start position:0% transparent and more powerful the main challenge<00:23:27.210> here<00:23:27.420> is<00:23:27.540> finding<00:23:28.110> good 00:23:28.160 --> 00:23:28.170 align:start position:0% challenge here is finding good 00:23:28.170 --> 00:23:31.610 align:start position:0% challenge here is finding good heuristics<00:23:28.710> per<00:23:28.950> step<00:23:29.130> as<00:23:29.520> I<00:23:29.640> explained<00:23:30.620> this 00:23:31.610 --> 00:23:31.620 align:start position:0% heuristics per step as I explained this 00:23:31.620 --> 00:23:36.950 align:start position:0% heuristics per step as I explained this will<00:23:32.010> not<00:23:32.130> impact<00:23:33.350> correctness<00:23:34.350> and<00:23:35.960> yeah 00:23:36.950 --> 00:23:36.960 align:start position:0% will not impact correctness and yeah 00:23:36.960 --> 00:23:40.430 align:start position:0% will not impact correctness and yeah code<00:23:37.950> size<00:23:38.280> is<00:23:38.580> always<00:23:38.850> an<00:23:38.940> important<00:23:39.440> measure 00:23:40.430 --> 00:23:40.440 align:start position:0% code size is always an important measure 00:23:40.440 --> 00:23:42.320 align:start position:0% code size is always an important measure whether<00:23:41.220> or<00:23:41.460> not<00:23:41.580> to<00:23:41.760> apply<00:23:41.940> some 00:23:42.320 --> 00:23:42.330 align:start position:0% whether or not to apply some 00:23:42.330 --> 00:23:44.810 align:start position:0% whether or not to apply some transformation<00:23:42.920> but<00:23:43.920> sometimes<00:23:44.520> it<00:23:44.670> makes 00:23:44.810 --> 00:23:44.820 align:start position:0% transformation but sometimes it makes 00:23:44.820 --> 00:23:48.370 align:start position:0% transformation but sometimes it makes sense<00:23:45.090> to<00:23:45.360> create<00:23:45.870> larger<00:23:46.320> court<00:23:46.590> larger<00:23:47.310> code 00:23:48.370 --> 00:23:48.380 align:start position:0% sense to create larger court larger code 00:23:48.380 --> 00:23:50.990 align:start position:0% sense to create larger court larger code in<00:23:49.380> intermediate<00:23:49.800> steps<00:23:50.190> that<00:23:50.580> can<00:23:50.820> be 00:23:50.990 --> 00:23:51.000 align:start position:0% in intermediate steps that can be 00:23:51.000 --> 00:23:58.930 align:start position:0% in intermediate steps that can be reduced<00:23:51.240> to<00:23:51.450> even<00:23:51.750> shorter<00:23:52.200> code<00:23:52.380> later<00:23:57.740> yeah 00:23:58.930 --> 00:23:58.940 align:start position:0% reduced to even shorter code later yeah 00:23:58.940 --> 00:24:02.210 align:start position:0% reduced to even shorter code later yeah just<00:23:59.940> some<00:24:00.180> quick<00:24:00.480> words<00:24:00.690> on<00:24:00.870> the<00:24:01.020> roadmap<00:24:01.230> we 00:24:02.210 --> 00:24:02.220 align:start position:0% just some quick words on the roadmap we 00:24:02.220 --> 00:24:05.300 align:start position:0% just some quick words on the roadmap we currently<00:24:02.640> implemented<00:24:03.770> most<00:24:04.770> of<00:24:05.010> the<00:24:05.100> steps 00:24:05.300 --> 00:24:05.310 align:start position:0% currently implemented most of the steps 00:24:05.310 --> 00:24:09.320 align:start position:0% currently implemented most of the steps we've<00:24:05.520> seen<00:24:05.850> here<00:24:06.240> apart<00:24:06.720> from<00:24:07.370> the<00:24:08.370> two<00:24:09.180> or 00:24:09.320 --> 00:24:09.330 align:start position:0% we've seen here apart from the two or 00:24:09.330 --> 00:24:11.780 align:start position:0% we've seen here apart from the two or three<00:24:09.510> loop<00:24:09.900> transformations<00:24:10.460> we've<00:24:11.460> seen 00:24:11.780 --> 00:24:11.790 align:start position:0% three loop transformations we've seen 00:24:11.790 --> 00:24:16.340 align:start position:0% three loop transformations we've seen and<00:24:12.320> now<00:24:13.320> the<00:24:13.380> next<00:24:14.190> step<00:24:14.340> is<00:24:14.580> to<00:24:15.350> implement 00:24:16.340 --> 00:24:16.350 align:start position:0% and now the next step is to implement 00:24:16.350 --> 00:24:19.930 align:start position:0% and now the next step is to implement these<00:24:16.620> loop<00:24:17.130> transformations<00:24:17.610> too<00:24:18.090> and 00:24:19.930 --> 00:24:19.940 align:start position:0% these loop transformations too and 00:24:19.940 --> 00:24:22.129 align:start position:0% these loop transformations too and check<00:24:20.940> that<00:24:21.149> all<00:24:21.389> the<00:24:21.419> transformations<00:24:22.019> are 00:24:22.129 --> 00:24:22.139 align:start position:0% check that all the transformations are 00:24:22.139 --> 00:24:25.580 align:start position:0% check that all the transformations are correct<00:24:22.940> and<00:24:23.940> then<00:24:24.240> we<00:24:24.450> will<00:24:24.629> apply<00:24:25.139> that<00:24:25.230> to 00:24:25.580 --> 00:24:25.590 align:start position:0% correct and then we will apply that to 00:24:25.590 --> 00:24:28.220 align:start position:0% correct and then we will apply that to the<00:24:25.710> a<00:24:25.740> bi<00:24:26.009> coder<00:24:26.549> take<00:24:26.999> the<00:24:27.179> ABI<00:24:27.419> KOTOR<00:24:27.990> out<00:24:28.110> of 00:24:28.220 --> 00:24:28.230 align:start position:0% the a bi coder take the ABI KOTOR out of 00:24:28.230 --> 00:24:32.840 align:start position:0% the a bi coder take the ABI KOTOR out of experimental<00:24:28.830> and<00:24:29.059> then<00:24:31.190> ya<00:24:32.190> make<00:24:32.669> the 00:24:32.840 --> 00:24:32.850 align:start position:0% experimental and then ya make the 00:24:32.850 --> 00:24:36.230 align:start position:0% experimental and then ya make the rewrite<00:24:33.240> of<00:24:33.269> the<00:24:33.509> solidity<00:24:34.379> compiler<00:24:34.830> and<00:24:35.240> at 00:24:36.230 --> 00:24:36.240 align:start position:0% rewrite of the solidity compiler and at 00:24:36.240 --> 00:24:39.470 align:start position:0% rewrite of the solidity compiler and at that<00:24:36.480> point<00:24:36.919> also<00:24:37.919> other<00:24:38.700> steps<00:24:38.999> might<00:24:39.299> make 00:24:39.470 --> 00:24:39.480 align:start position:0% that point also other steps might make 00:24:39.480 --> 00:24:41.659 align:start position:0% that point also other steps might make sense<00:24:39.690> that<00:24:39.899> do<00:24:39.990> not<00:24:40.110> make<00:24:40.289> sense<00:24:40.350> in<00:24:40.860> the<00:24:41.340> ABI 00:24:41.659 --> 00:24:41.669 align:start position:0% sense that do not make sense in the ABI 00:24:41.669 --> 00:24:44.149 align:start position:0% sense that do not make sense in the ABI coder<00:24:41.999> so<00:24:42.120> we<00:24:42.419> will<00:24:42.600> continually<00:24:43.350> improve<00:24:43.830> the 00:24:44.149 --> 00:24:44.159 align:start position:0% coder so we will continually improve the 00:24:44.159 --> 00:24:46.549 align:start position:0% coder so we will continually improve the optimizer<00:24:44.999> there<00:24:45.409> thanks<00:24:46.409> for<00:24:46.499> your 00:24:46.549 --> 00:24:46.559 align:start position:0% optimizer there thanks for your 00:24:46.559 --> 00:24:47.610 align:start position:0% optimizer there thanks for your attention 00:24:47.610 --> 00:24:47.620 align:start position:0% attention 00:24:47.620 --> 00:24:59.170 align:start position:0% attention [Applause] 00:24:59.170 --> 00:24:59.180 align:start position:0% 00:24:59.180 --> 00:25:01.240 align:start position:0% you