Search code, repositories, users, issues, pull requests...

@scottmcm scottmcm force-pushed the tweak-if-const branch from c9c3092 to 2fb9d27 Compare

March 31, 2024 07:15

scottmcm

scottmcm commented

tests/mir-opt/pre-codegen/slice_iter.forward_loop.PreCodegen.after.panic-abort.mir Outdated

@@ -25,19 +25,18 @@ fn forward_loop(_1: &[T], _2: impl Fn(&T)) -> () {

debug slice => _1;

let _3: usize;

let mut _5: std::ptr::NonNull<[T]>;

let mut _8: bool;

Copy link

Member Author

@scottmcm scottmcm Mar 31, 2024

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This PR means this local -- and its associated storage markers -- are no longer needed.

Copy link

Member Author

scottmcm commented Mar 31, 2024

@bors try @rust-timer queue

@rust-timer

This comment has been minimized.

@rustbot rustbot added the S-waiting-on-perf label

@bors

Copy link

Collaborator

bors commented Mar 31, 2024

⌛ Trying commit 2fb9d27 with merge 3d3fbc3...

bors added a commit to rust-lang-ci/rust that referenced this pull request

@bors


 Auto merge of rust-lang#123259 - scottmcm:tweak-if-const, r=<try>

3d3fbc3

Fixup `if T::CONST` in MIR
r? ghost

RalfJung

RalfJung reviewed

compiler/rustc_mir_transform/src/switch_const.rs

/// A `MirPass` for simplifying `if T::CONST`.

///

/// Today, MIR building for things like `if T::IS_ZST` introduce a constant

Copy link

Member

@RalfJung RalfJung Mar 31, 2024

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Suggested change

/// Today, MIR building for things like `if T::IS_ZST` introduce a constant

/// Today, MIR building for things like `if T::IS_ZST` introduce a temporary

RalfJung

RalfJung reviewed

compiler/rustc_mir_transform/src/switch_const.rs

#[derive(Default)]

pub struct SwitchConst;

impl<'tcx> MirPass<'tcx> for SwitchConst {

Copy link

Member

@RalfJung RalfJung Mar 31, 2024

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Note that as a pass that runs in opt-level 0, this pass should not do UB-based reasoning or transform code with UB into code without UB. Miri relies on that.

The pass seems fine but this is worth pointing out with a comment as the requirement is implicit in the absence of an opt-level check.

@bors

Copy link

Collaborator

bors commented Mar 31, 2024

☀️ Try build successful - checks-actions
Build commit: 3d3fbc3 (3d3fbc3c91e604af5b9b333f21043027fab15906)

@rust-timer

This comment has been minimized.

bjorn3

bjorn3 reviewed

compiler/rustc_codegen_ssa/src/mir/block.rs

let target = targets.target_for_value(const_discr);

bx.br(helper.llbb_with_cleanup(self, target));

return;

};

}

Copy link

Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Note to self: cg_clif needs this too

@rust-timer

Copy link

Collaborator

rust-timer commented Mar 31, 2024

Finished benchmarking commit (3d3fbc3): comparison URL.

Overall result: ❌✅ regressions and improvements - 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.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@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)	0.6%	[0.4%, 0.9%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.6%	[-1.3%, -0.2%]	6
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.2%	[-1.3%, 0.9%]	9

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)	2.0%	[0.2%, 3.3%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-4.6%	[-4.6%, -4.6%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.4%	[-4.6%, 3.3%]	4

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)	0.9%	[0.8%, 1.1%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.2%	[-1.2%, -1.2%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[-1.2%, 1.1%]	3

Binary size

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)	0.6%	[0.1%, 2.0%]	62
Regressions ❌ (secondary)	0.5%	[0.2%, 2.7%]	18
Improvements ✅ (primary)	-0.4%	[-0.8%, -0.1%]	14
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.4%	[-0.8%, 2.0%]	76

Bootstrap: 668.042s -> 671.806s (0.56%)
Artifact size: 315.71 MiB -> 315.75 MiB (0.01%)

@rustbot rustbot added perf-regression and removed S-waiting-on-perf labels

@Dylan-DPC Dylan-DPC added S-experimental and removed S-waiting-on-review labels

May 5, 2024

scottmcm added 3 commits

July 4, 2024 17:58


 Add a mir pre-codegen test for if T::ASSOC_CONST

a1e3451


 Move constants into the SwitchInt to be easier to see

0d804b9