Only clear written-to locals in ConstProp #109087

cjgillot · 2023-03-13T18:15:50Z

This aims to revert the regression in #108872

Clearing all locals at the end of each bb is very costly.
This PR goes back to the original implementation of recording which locals are modified.

rustbot · 2023-03-13T18:15:56Z

r? @davidtwco

(rustbot has picked a reviewer for you, use r? to override)

rustbot · 2023-03-13T18:15:59Z

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

cjgillot · 2023-03-13T18:16:16Z

@bors try @rust-timer queue

bors · 2023-03-13T18:16:28Z

⌛ Trying commit f1639046613c8a2d8d145b6988f07e483e6493c8 with merge b366731ad56f28626f3195de1a16febed2a84475...

Noratrieb · 2023-03-13T18:23:35Z

compiler/rustc_mir_transform/src/const_prop_lint.rs

+        self.ecx.machine.written_only_inside_own_block_locals =
+            written_only_inside_own_block_locals;
+
+        #[cfg(debug_assertions)]


could you turn this into an if cfg!(debug_assertions) instead? it does increase the indentation slightly but it's a lot nicer to work with

bors · 2023-03-13T21:04:55Z

☀️ Try build successful - checks-actions
Build commit: b366731ad56f28626f3195de1a16febed2a84475 (b366731ad56f28626f3195de1a16febed2a84475)

rust-timer · 2023-03-14T01:38:21Z

Finished benchmarking commit (b366731ad56f28626f3195de1a16febed2a84475): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.5%	[-6.2%, -0.6%]	30
Improvements ✅ (secondary)	-18.0%	[-59.1%, -0.4%]	14
All ❌✅ (primary)	-2.5%	[-6.2%, -0.6%]	30

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.6%	[2.6%, 2.6%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.5%	[-2.0%, -1.1%]	7
Improvements ✅ (secondary)	-17.2%	[-34.2%, -4.1%]	8
All ❌✅ (primary)	-1.5%	[-2.0%, -1.1%]	7

davidtwco

r=me, resolving nils comment if you want

nnethercote · 2023-03-19T05:24:01Z

Oh dear: #108815 was a big improvement for keccak and cranelift-codegen. Unfortunately, it was merged between #108872 (which massively regressed those benchmarks) and this PR (which mostly?/entirely? fixes the regression). It will be tricky to disentangle the individual perf effects of the three PRs.

cc @the8472

cjgillot · 2023-03-19T09:08:29Z

@bors r=davidtwco

bors · 2023-03-19T09:08:31Z

📌 Commit e5a55dc has been approved by davidtwco

It is now in the queue for this repository.

bors · 2023-03-21T17:51:58Z

⌛ Testing commit e5a55dc with merge 309b33d943f412e3c1c3235cf01ee083d7ec1dd9...

bors · 2023-03-21T18:08:38Z

💔 Test failed - checks-actions

rust-log-analyzer · 2023-03-21T20:43:23Z

The job x86_64-mingw-2 failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

[2529/3025] Building CXX object lib/ToolDrivers/llvm-lib/CMakeFiles/LLVMLibDriver.dir/LibDriver.cpp.obj
[2530/3025] Building CXX object lib/XRay/CMakeFiles/LLVMXRay.dir/BlockVerifier.cpp.obj
[2531/3025] Linking CXX static library lib\libLLVMDebugInfoDWARF.a
[2532/3025] Linking CXX static library lib\libLLVMRuntimeDyld.a
FAILED: lib/libLLVMRuntimeDyld.a 
cmd.exe /C "cd . && "C:\Program Files\CMake\bin\cmake.exe" -E rm -f lib\libLLVMRuntimeDyld.a && C:\a\rust\rust\mingw64\bin\ar.exe qc lib\libLLVMRuntimeDyld.a  lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/JITSymbol.cpp.obj lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/RTDyldMemoryManager.cpp.obj lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/RuntimeDyld.cpp.obj lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/RuntimeDyldChecker.cpp.obj lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/RuntimeDyldCOFF.cpp.obj lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/RuntimeDyldELF.cpp.obj lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/RuntimeDyldMachO.cpp.obj lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/Targets/RuntimeDyldELFMips.cpp.obj && C:\a\rust\rust\mingw64\bin\ranlib.exe lib\libLLVMRuntimeDyld.a && cd ."
C:\a\rust\rust\mingw64\bin\ar.exe: could not create temporary file whilst writing archive: no more archived files
[2533/3025] Linking CXX static library lib\libLLVMObjCopy.a
[2534/3025] Building CXX object lib/XRay/CMakeFiles/LLVMXRay.dir/Profile.cpp.obj
[2535/3025] Linking CXX static library lib\libLLVMJITLink.a
[2536/3025] Linking CXX static library lib\libLLVMDebugInfoGSYM.a
[2536/3025] Linking CXX static library lib\libLLVMDebugInfoGSYM.a
[2537/3025] Building CXX object lib/XRay/CMakeFiles/LLVMXRay.dir/RecordPrinter.cpp.obj
[2538/3025] Linking CXX static library lib\libLLVMDebugInfoPDB.a
[2539/3025] Linking CXX static library lib\libLLVMObjectYAML.a
ninja: build stopped: subcommand failed.
command did not execute successfully, got: exit code: 1


build script failed, must exit now', C:\Users\runneradmin\.cargo\registry\src\index.crates.io-6f17d22bba15001f\cmake-0.1.48\src\lib.rs:975:5
 finished in 280.692 seconds
Build completed unsuccessfully in 0:05:51
Build completed unsuccessfully in 0:05:51
make: *** [Makefile:80: ci-mingw-subset-2] Error 1

nnethercote · 2023-03-22T00:14:01Z

Failure while building LLVM:

could not create temporary file whilst writing archive: no more archived files

Seems like a transient error unrelated to this PR.

@bors retry

bors · 2023-03-22T02:49:07Z

⌛ Testing commit e5a55dc with merge 5fa73a7...

bors · 2023-03-22T05:33:11Z

☀️ Test successful - checks-actions
Approved by: davidtwco
Pushing 5fa73a7 to master...

rust-timer · 2023-03-22T13:14:22Z

Finished benchmarking commit (5fa73a7): comparison URL.

Overall result: ❌✅ regressions and improvements - ACTION NEEDED

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.5%	[0.5%, 0.5%]	3
Improvements ✅ (primary)	-2.7%	[-6.1%, -0.8%]	27
Improvements ✅ (secondary)	-15.8%	[-63.2%, -0.2%]	17
All ❌✅ (primary)	-2.7%	[-6.1%, -0.8%]	27

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.9%	[0.5%, 1.3%]	10
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.8%	[0.4%, 1.4%]	5
Improvements ✅ (primary)	-1.5%	[-1.9%, -1.0%]	6
Improvements ✅ (secondary)	-14.6%	[-36.5%, -0.6%]	10
All ❌✅ (primary)	-1.5%	[-1.9%, -1.0%]	6

rylev · 2023-03-28T13:13:59Z

Given the overall positive impact of this PR and the complex relationship it has with some other PRs, I think it's safe to say the perf results are fine here.

@rustbot label: +perf-regression-triaged

rustbot assigned davidtwco Mar 13, 2023

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 13, 2023

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 13, 2023

Noratrieb reviewed Mar 13, 2023

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 14, 2023

davidtwco approved these changes Mar 16, 2023

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cjgillot added 2 commits March 19, 2023 08:58

Only clear locals that are known to be written to.

0e866af

Prefer if cfg!.

e5a55dc

cjgillot force-pushed the sparse-bb-clear branch from f163904 to e5a55dc Compare March 19, 2023 09:00

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 19, 2023

bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Mar 21, 2023

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 22, 2023

bors added the merged-by-bors This PR was explicitly merged by bors. label Mar 22, 2023

bors merged commit 5fa73a7 into rust-lang:master Mar 22, 2023

rustbot added this to the 1.70.0 milestone Mar 22, 2023

cjgillot deleted the sparse-bb-clear branch March 22, 2023 07:40

rustbot added the perf-regression Performance regression. label Mar 22, 2023

rustbot added the perf-regression-triaged The performance regression has been triaged. label Mar 28, 2023

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Only clear written-to locals in ConstProp #109087

Only clear written-to locals in ConstProp #109087

cjgillot commented Mar 13, 2023

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rylev commented Mar 28, 2023

Only clear written-to locals in ConstProp #109087

Only clear written-to locals in ConstProp #109087

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Overall result: ✅ improvements - no action needed

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rust-timer commented Mar 22, 2023

Overall result: ❌✅ regressions and improvements - ACTION NEEDED

Instruction count

Max RSS (memory usage)

Cycles

rylev commented Mar 28, 2023