Cache flags for `ty::Const` #118189

compiler-errors · 2023-11-22T23:29:17Z

Not sure if this has been attempted yet, but worth a shot. It does make the code simpler in rustc_type_ir, since we can assume that consts have a flags method that is no-cost.

r? @ghost

compiler-errors · 2023-11-22T23:29:24Z

@bors try @rust-timer queue

bors · 2023-11-22T23:30:34Z

⌛ Trying commit 4ec6857 with merge d300094...

…t, r=<try> Cache flags for `ty::Const` Not sure if this has been attempted yet, but worth a shot. It does make the code simpler in `rustc_type_ir`, since we can assume that consts have a `flags` method that is no-cost. r? `@ghost`

bors · 2023-11-23T00:56:36Z

☀️ Try build successful - checks-actions
Build commit: d300094 (d3000946843e316f5e0045ed65a24d07e853f03b)

rust-timer · 2023-11-23T11:51:31Z

Finished benchmarking commit (d300094): 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)	-0.3%	[-0.4%, -0.2%]	12
Improvements ✅ (secondary)	-0.2%	[-0.3%, -0.2%]	4
All ❌✅ (primary)	-0.3%	[-0.4%, -0.2%]	12

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)	3.9%	[3.8%, 4.0%]	2
Regressions ❌ (secondary)	1.2%	[1.2%, 1.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.2%	[-1.2%, -1.2%]	1
All ❌✅ (primary)	3.9%	[3.8%, 4.0%]	2

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 675.896s -> 674.726s (-0.17%)
Artifact size: 313.66 MiB -> 313.53 MiB (-0.04%)

compiler-errors · 2023-11-24T02:09:36Z

cool beans

r? @nnethercote

you have any idea why this wasn't attempted sooner? i may be missing some history/background of WithCachedTypeInfo, and i feel like you'd know it, since you're the perf guy.

compiler-errors

There are likely other folders/visiting that could take advantage of the fact that consts have an O(1) flag/outer_exclusive_binder computation, and short-circuit folding/visiting in this case. I'll leave that up to follow-ups.

compiler-errors · 2023-11-24T02:11:28Z

compiler/rustc_middle/src/ty/flags.rs

@@ -28,10 +28,11 @@ impl FlagComputation {
        result
    }

-    pub fn for_const(c: ty::Const<'_>) -> TypeFlags {
+    pub fn for_const(c: &ty::ConstKind<'_>, t: Ty<'_>) -> FlagComputation {


Maybe this should take &ConstData?

compiler-errors · 2023-11-24T02:11:48Z

compiler/rustc_middle/src/ty/flags.rs

+        self.add_exclusive_binder(c.outer_exclusive_binder());
+    }
+
+    fn add_const_kind(&mut self, c: &ty::ConstKind<'_>) {


I actually am unsure if it's more efficient just to take the ConstKind by value here.

nnethercote · 2023-11-24T04:32:19Z

I think @oli-obk added WithCachedTypeInfo. I suspect consts weren't done just because they're so much less common than types, so the potential wins are a lot smaller.

@bors r+

bors · 2023-11-24T04:32:21Z

📌 Commit 4ec6857 has been approved by nnethercote

It is now in the queue for this repository.

bors · 2023-11-24T04:54:38Z

⌛ Testing commit 4ec6857 with merge 41fe75e...

bors · 2023-11-24T07:21:54Z

☀️ Test successful - checks-actions
Approved by: nnethercote
Pushing 41fe75e to master...

rust-timer · 2023-11-24T09:42:16Z

Finished benchmarking commit (41fe75e): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -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)	-0.3%	[-0.3%, -0.2%]	10
Improvements ✅ (secondary)	-0.3%	[-0.3%, -0.2%]	3
All ❌✅ (primary)	-0.3%	[-0.3%, -0.2%]	10

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)	2.1%	[2.1%, 2.1%]	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)	1.2%	[1.2%, 1.2%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.2%	[1.2%, 1.2%]	1

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 675.697s -> 676.001s (0.04%)
Artifact size: 313.74 MiB -> 313.55 MiB (-0.06%)

Cache flags for ty::Const

4ec6857

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 Nov 22, 2023

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Nov 23, 2023

compiler-errors marked this pull request as ready for review November 24, 2023 02:09

rustbot assigned nnethercote Nov 24, 2023

compiler-errors commented Nov 24, 2023

View reviewed changes

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 Nov 24, 2023

bors added the merged-by-bors This PR was explicitly merged by bors. label Nov 24, 2023

bors merged commit 41fe75e into rust-lang:master Nov 24, 2023
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rustbot added this to the 1.76.0 milestone Nov 24, 2023

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Cache flags for `ty::Const` #118189

Cache flags for `ty::Const` #118189

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Cache flags for ty::Const #118189

Cache flags for ty::Const #118189

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Overall result: ✅ improvements - no action needed

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nnethercote commented Nov 24, 2023

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rust-timer commented Nov 24, 2023

Overall result: ✅ improvements - no action needed

Cache flags for `ty::Const` #118189

Cache flags for `ty::Const` #118189

compiler-errors commented Nov 24, 2023 •

edited