Experimental variant on #57465 with two optimizations

[danvk]

This adds two optimizations to #57465:

• For the false check, if trueType is a large union (20+ constituents) then split it into two chunks when calling getFlowTypeOfReference. The first chunk has the first 10 types, the second has the remainder. If the first chunk doesn't narrow to never then we don't have to check the second. This is a huge win on Use union types for all common classes of AST nodes #54148. On my laptop it reduces the time for the most extreme check from 312ms→140ms by only checking 10/112 types in the union. There are several other expensive calls on that PR that it's able to bypass as well. This has less of an effect on the Compiler-Unions benchmark.
• A fast path for functions of the form x => x === y (or ==, !==, !=). These can only be type predicates if y is a unit type like null or undefined, but that can be expensive to determine via the usual calls to getFlowTypeOfReference if x and y are both large union types. In both Compiler-Unions and Use union types for all common classes of AST nodes #54148 there are some expensive checks that this bypasses, notably d => d === objectLiteralDeclaration.

In local testing these help on both Compiler-Unions and #54148. The x === y optimization is definitely targeted at a specific case in Compiler-Unions, but it's a win on #54148 as well, so perhaps it does generalize.

[jakebailey]

@typescript-bot perf test this

[typescript-bot]

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
perf test this	✅ Started	👀 Results

[typescript-bot]

@jakebailey
The results of the perf run you requested are in!

Here they are:

tsc

Comparison Report - baseline..pr

Metric	baseline	pr	Delta	Best	Worst	p-value
Angular - node (v18.15.0, x64)
Memory used	295,565k (± 0.00%)	295,585k (± 0.01%)	~	295,516k	295,620k	p=0.230 n=6
Parse Time	2.66s (± 0.28%)	2.66s (± 0.51%)	~	2.64s	2.67s	p=0.672 n=6
Bind Time	0.83s (± 0.62%)	0.83s (± 0.76%)	~	0.82s	0.84s	p=0.386 n=6
Check Time	8.22s (± 0.18%)	8.21s (± 0.37%)	~	8.19s	8.27s	p=0.415 n=6
Emit Time	7.10s (± 0.43%)	7.10s (± 0.19%)	~	7.08s	7.12s	p=0.806 n=6
Total Time	18.81s (± 0.14%)	18.80s (± 0.14%)	~	18.77s	18.84s	p=0.627 n=6
Compiler-Unions - node (v18.15.0, x64)
Memory used	192,120k (± 0.73%)	192,445k (± 0.71%)	+325k (+ 0.17%)	191,772k	195,220k	p=0.045 n=6
Parse Time	1.35s (± 0.98%)	1.37s (± 1.01%)	~	1.35s	1.38s	p=0.156 n=6
Bind Time	0.72s (± 0.00%)	0.72s (± 0.00%)	~	0.72s	0.72s	p=1.000 n=6
Check Time	9.36s (± 0.50%)	9.52s (± 0.32%)	+0.16s (+ 1.71%)	9.47s	9.55s	p=0.005 n=6
Emit Time	2.61s (± 0.66%)	2.61s (± 0.78%)	~	2.59s	2.64s	p=0.870 n=6
Total Time	14.04s (± 0.35%)	14.22s (± 0.22%)	+0.18s (+ 1.26%)	14.17s	14.26s	p=0.005 n=6
Monaco - node (v18.15.0, x64)
Memory used	347,339k (± 0.00%)	347,384k (± 0.00%)	+45k (+ 0.01%)	347,370k	347,395k	p=0.005 n=6
Parse Time	2.48s (± 0.42%)	2.48s (± 0.47%)	~	2.47s	2.50s	p=0.801 n=6
Bind Time	0.93s (± 0.56%)	0.93s (± 0.56%)	~	0.92s	0.93s	p=1.000 n=6
Check Time	6.97s (± 0.34%)	6.99s (± 0.34%)	~	6.95s	7.02s	p=0.056 n=6
Emit Time	4.06s (± 0.31%)	4.09s (± 0.33%)	+0.03s (+ 0.66%)	4.07s	4.11s	p=0.014 n=6
Total Time	14.43s (± 0.25%)	14.48s (± 0.22%)	+0.05s (+ 0.35%)	14.43s	14.52s	p=0.037 n=6
TFS - node (v18.15.0, x64)
Memory used	302,784k (± 0.01%)	302,754k (± 0.01%)	~	302,712k	302,809k	p=0.128 n=6
Parse Time	2.00s (± 1.17%)	2.00s (± 0.86%)	~	1.98s	2.03s	p=0.459 n=6
Bind Time	1.01s (± 1.31%)	1.00s (± 1.04%)	~	0.99s	1.02s	p=0.451 n=6
Check Time	6.33s (± 0.28%)	6.34s (± 0.49%)	~	6.29s	6.38s	p=0.803 n=6
Emit Time	3.61s (± 0.34%)	3.61s (± 0.41%)	~	3.59s	3.63s	p=0.934 n=6
Total Time	12.96s (± 0.30%)	12.95s (± 0.16%)	~	12.93s	12.99s	p=0.295 n=6
material-ui - node (v18.15.0, x64)
Memory used	511,211k (± 0.00%)	511,251k (± 0.01%)	~	511,186k	511,373k	p=0.078 n=6
Parse Time	2.65s (± 0.81%)	2.66s (± 0.51%)	~	2.64s	2.67s	p=0.365 n=6
Bind Time	0.99s (± 0.99%)	0.99s (± 1.23%)	~	0.97s	1.00s	p=0.865 n=6
Check Time	17.24s (± 0.23%)	17.31s (± 0.50%)	~	17.19s	17.43s	p=0.146 n=6
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	~	0.00s	0.00s	p=1.000 n=6
Total Time	20.88s (± 0.22%)	20.95s (± 0.41%)	~	20.84s	21.08s	p=0.128 n=6
mui-docs - node (v18.15.0, x64)
Memory used	2,296,341k (± 0.00%)	2,296,522k (± 0.00%)	+181k (+ 0.01%)	2,296,497k	2,296,573k	p=0.005 n=6
Parse Time	11.98s (± 0.81%)	11.97s (± 0.75%)	~	11.87s	12.13s	p=1.000 n=6
Bind Time	2.66s (± 0.69%)	2.64s (± 0.31%)	~	2.63s	2.65s	p=0.121 n=6
Check Time	101.41s (± 0.87%)	101.53s (± 0.66%)	~	100.73s	102.62s	p=1.000 n=6
Emit Time	0.32s (± 1.60%)	0.32s (± 1.97%)	~	0.31s	0.33s	p=0.386 n=6
Total Time	116.37s (± 0.81%)	116.47s (± 0.57%)	~	115.64s	117.55s	p=1.000 n=6
self-build-src - node (v18.15.0, x64)
Memory used	2,394,444k (± 0.01%)	2,396,586k (± 0.03%)	+2,142k (+ 0.09%)	2,395,763k	2,397,458k	p=0.005 n=6
Parse Time	5.04s (± 1.25%)	5.05s (± 1.49%)	~	4.94s	5.14s	p=0.748 n=6
Bind Time	1.89s (± 0.43%)	1.90s (± 0.86%)	~	1.87s	1.92s	p=0.605 n=6
Check Time	33.61s (± 0.31%)	33.68s (± 0.22%)	~	33.59s	33.81s	p=0.173 n=6
Emit Time	2.64s (± 0.99%)	2.66s (± 1.49%)	~	2.59s	2.70s	p=0.295 n=6
Total Time	43.19s (± 0.27%)	43.30s (± 0.33%)	~	43.17s	43.52s	p=0.689 n=6
self-compiler - node (v18.15.0, x64)
Memory used	414,431k (± 0.01%)	415,047k (± 0.01%)	+616k (+ 0.15%)	415,001k	415,088k	p=0.005 n=6
Parse Time	2.82s (± 0.70%)	2.79s (± 0.84%)	~	2.76s	2.82s	p=0.087 n=6
Bind Time	1.07s (± 0.48%)	1.07s (± 0.51%)	~	1.06s	1.07s	p=0.640 n=6
Check Time	15.14s (± 0.40%)	15.26s (± 0.29%)	+0.12s (+ 0.78%)	15.19s	15.32s	p=0.008 n=6
Emit Time	1.10s (± 1.33%)	1.11s (± 1.47%)	~	1.08s	1.12s	p=0.564 n=6
Total Time	20.13s (± 0.40%)	20.22s (± 0.33%)	~	20.13s	20.32s	p=0.093 n=6
vscode - node (v18.15.0, x64)
Memory used	2,859,177k (± 0.01%)	2,859,763k (± 0.00%)	+586k (+ 0.02%)	2,859,683k	2,859,806k	p=0.005 n=6
Parse Time	10.76s (± 0.11%)	10.76s (± 0.35%)	~	10.71s	10.81s	p=1.000 n=6
Bind Time	3.44s (± 0.12%)	3.44s (± 0.34%)	~	3.43s	3.46s	p=0.584 n=6
Check Time	61.28s (± 0.29%)	61.16s (± 0.55%)	~	60.69s	61.49s	p=0.688 n=6
Emit Time	17.41s (±10.15%)	16.33s (± 0.40%)	~	16.25s	16.44s	p=0.810 n=6
Total Time	92.89s (± 1.89%)	91.68s (± 0.36%)	~	91.26s	92.05s	p=0.173 n=6
webpack - node (v18.15.0, x64)
Memory used	397,024k (± 0.01%)	397,141k (± 0.02%)	+117k (+ 0.03%)	397,049k	397,211k	p=0.013 n=6
Parse Time	3.13s (± 0.94%)	3.14s (± 0.77%)	~	3.10s	3.17s	p=0.373 n=6
Bind Time	1.38s (± 1.63%)	1.39s (± 1.55%)	~	1.37s	1.43s	p=0.105 n=6
Check Time	13.93s (± 0.31%)	14.06s (± 0.40%)	+0.13s (+ 0.95%)	13.97s	14.13s	p=0.008 n=6
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	~	0.00s	0.00s	p=1.000 n=6
Total Time	18.44s (± 0.18%)	18.60s (± 0.22%)	+0.16s (+ 0.87%)	18.54s	18.64s	p=0.005 n=6
xstate - node (v18.15.0, x64)
Memory used	513,132k (± 0.01%)	513,198k (± 0.02%)	~	513,106k	513,414k	p=0.298 n=6
Parse Time	3.28s (± 0.36%)	3.27s (± 0.37%)	~	3.26s	3.29s	p=0.507 n=6
Bind Time	1.54s (± 0.49%)	1.54s (± 0.49%)	~	1.53s	1.55s	p=0.487 n=6
Check Time	2.86s (± 0.41%)	2.87s (± 0.90%)	~	2.83s	2.90s	p=0.618 n=6
Emit Time	0.08s (± 0.00%)	0.07s (± 0.00%)	🟩-0.01s (-12.50%)	0.07s	0.07s	p=0.001 n=6
Total Time	7.76s (± 0.28%)	7.77s (± 0.35%)	~	7.73s	7.81s	p=0.688 n=6

System info unknown

Hosts

• node (v18.15.0, x64)

Scenarios

• Angular - node (v18.15.0, x64)
• Compiler-Unions - node (v18.15.0, x64)
• Monaco - node (v18.15.0, x64)
• TFS - node (v18.15.0, x64)
• material-ui - node (v18.15.0, x64)
• mui-docs - node (v18.15.0, x64)
• self-build-src - node (v18.15.0, x64)
• self-compiler - node (v18.15.0, x64)
• vscode - node (v18.15.0, x64)
• webpack - node (v18.15.0, x64)
• xstate - node (v18.15.0, x64)

Benchmark	Name	Iterations
Current	pr	6
Baseline	baseline	6

tsserver

Comparison Report - baseline..pr

Metric	baseline	pr	Delta	Best	Worst	p-value
Compiler-UnionsTSServer - node (v18.15.0, x64)
Req 1 - updateOpen	2,354ms (± 0.85%)	2,365ms (± 0.58%)	~	2,354ms	2,391ms	p=0.230 n=6
Req 2 - geterr	5,580ms (± 1.00%)	5,585ms (± 0.36%)	~	5,564ms	5,620ms	p=0.936 n=6
Req 3 - references	328ms (± 1.27%)	330ms (± 0.97%)	~	324ms	333ms	p=0.624 n=6
Req 4 - navto	274ms (± 0.79%)	274ms (± 0.00%)	~	274ms	274ms	p=1.000 n=6
Req 5 - completionInfo count	1,357 (± 0.00%)	1,357 (± 0.00%)	~	1,357	1,357	p=1.000 n=6
Req 5 - completionInfo	86ms (± 7.52%)	79ms (± 0.65%)	~	79ms	80ms	p=0.103 n=6
CompilerTSServer - node (v18.15.0, x64)
Req 1 - updateOpen	2,522ms (± 0.42%)	2,514ms (± 0.53%)	~	2,493ms	2,532ms	p=0.228 n=6
Req 2 - geterr	4,195ms (± 1.94%)	4,177ms (± 0.52%)	~	4,152ms	4,214ms	p=1.000 n=6
Req 3 - references	344ms (± 6.92%)	333ms (± 0.23%)	~	332ms	334ms	p=0.565 n=6
Req 4 - navto	284ms (± 1.03%)	285ms (± 0.29%)	~	285ms	287ms	p=1.000 n=6
Req 5 - completionInfo count	1,519 (± 0.00%)	1,519 (± 0.00%)	~	1,519	1,519	p=1.000 n=6
Req 5 - completionInfo	81ms (± 8.93%)	76ms (± 5.92%)	~	74ms	85ms	p=0.157 n=6
xstateTSServer - node (v18.15.0, x64)
Req 1 - updateOpen	2,608ms (± 0.24%)	2,597ms (± 0.67%)	~	2,567ms	2,620ms	p=0.170 n=6
Req 2 - geterr	1,750ms (± 2.03%)	1,741ms (± 2.90%)	~	1,659ms	1,786ms	p=0.873 n=6
Req 3 - references	123ms (± 6.76%)	118ms (± 9.54%)	~	105ms	128ms	p=0.872 n=6
Req 4 - navto	373ms (± 3.08%)	369ms (± 1.30%)	~	360ms	373ms	p=0.936 n=6
Req 5 - completionInfo count	2,079 (± 0.00%)	2,079 (± 0.00%)	~	2,079	2,079	p=1.000 n=6
Req 5 - completionInfo	305ms (± 1.08%)	307ms (± 1.61%)	~	301ms	313ms	p=0.810 n=6

System info unknown

Hosts

• node (v18.15.0, x64)

Scenarios

• CompilerTSServer - node (v18.15.0, x64)
• Compiler-UnionsTSServer - node (v18.15.0, x64)
• xstateTSServer - node (v18.15.0, x64)

Benchmark	Name	Iterations
Current	pr	6
Baseline	baseline	6

startup

Comparison Report - baseline..pr

Metric	baseline	pr	Delta	Best	Worst	p-value
tsc-startup - node (v18.15.0, x64)
Execution time	153.07ms (± 0.18%)	153.08ms (± 0.17%)	~	152.14ms	155.04ms	p=0.618 n=600
tsserver-startup - node (v18.15.0, x64)
Execution time	229.04ms (± 0.17%)	228.70ms (± 0.17%)	-0.34ms (- 0.15%)	227.37ms	231.75ms	p=0.000 n=600
tsserverlibrary-startup - node (v18.15.0, x64)
Execution time	221.72ms (± 0.17%)	221.75ms (± 0.16%)	~	219.92ms	227.86ms	p=0.159 n=600
typescript-startup - node (v18.15.0, x64)
Execution time	221.79ms (± 0.16%)	221.78ms (± 0.15%)	~	220.19ms	226.38ms	p=0.991 n=600

System info unknown

Hosts

• node (v18.15.0, x64)

Scenarios

• tsc-startup - node (v18.15.0, x64)
• tsserver-startup - node (v18.15.0, x64)
• tsserverlibrary-startup - node (v18.15.0, x64)
• typescript-startup - node (v18.15.0, x64)

Benchmark	Name	Iterations
Current	pr	6
Baseline	baseline	6

Developer Information:

Download Benchmarks

[danvk]

I'm surprised this wasn't a win. Might be time to stop optimizing this!