Do not clone the Body for ConstProp

[cjgillot]

Based on #115748 for the POST_MONO_CHECKS flag.

[rustbot]

r? @davidtwco

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

[rustbot]

Some changes occurred in const_evaluatable.rs

cc @BoxyUwU

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

Some changes might have occurred in exhaustiveness checking

cc @Nadrieril

Some changes occurred to the core trait solver

cc @rust-lang/initiative-trait-system-refactor

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

[RalfJung]

Which part of #115748 do you need? If it's just the flag to skip the required_consts loop, it might be easier to just have a single commit with that. I expect that PR to potentially take a bit.

[RalfJung]

Turns out this is not the entire reason, with const-generics we (try to) run regular CTFE on generic MIR as well.

It's just, we really don't need the post-mono checks here since we're not actually doing evaluation.

[cjgillot]

@bors try @rust-timer queue

[bors]

⌛ Trying commit d0cba3d with merge 438955f...

[blyxyas]

Is there an error with bors or has there been a point in time where this PR modified other submodules (at least, it doesn't modify any Clippy files)? I can't find any commit that modifies one of these files. 🤷‍♀️

[cjgillot]

No issue with bors. Just me being lazy and cherry-picking a large commit instead of re-coding 8 lines.

[bors]

☀️ Try build successful - checks-actions
Build commit: 438955f (438955f5517859a3ed112a9da26ddb927c256fbb)

[rust-timer]

Finished benchmarking commit (438955f): comparison URL.

Overall result: no relevant changes - 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 benchmark run did not return any relevant results for this metric.

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
Improvements ✅ (primary)	-1.4%	[-1.4%, -1.4%]	1
Improvements ✅ (secondary)	-3.3%	[-4.5%, -1.5%]	5
All ❌✅ (primary)	-1.4%	[-1.4%, -1.4%]	1

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)	2.3%	[2.3%, 2.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 632.565s -> 631.473s (-0.17%)
Artifact size: 317.90 MiB -> 318.05 MiB (0.05%)

[oli-obk]

@bors r+

[bors]

📌 Commit d0cba3d has been approved by oli-obk

It is now in the queue for this repository.

[bors]

⌛ Testing commit d0cba3d with merge 5adddad...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 5adddad to master...

[rust-timer]

Finished benchmarking commit (5adddad): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

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

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: 632.671s -> 632.02s (-0.10%)
Artifact size: 317.85 MiB -> 317.95 MiB (0.03%)

[klensy]

Can this be applied to const_prop_lint too? Code looks c&p at some places.

rust/compiler/rustc_mir_transform/src/const_prop_lint.rs

Lines 108 to 119 in 56e1aaa

	let dummy_body = &Body::new(
	body.source,
	(*body.basic_blocks).to_owned(),
	body.source_scopes.clone(),
	body.local_decls.clone(),
	Default::default(),
	body.arg_count,
	Default::default(),
	body.span,
	body.generator_kind(),
	body.tainted_by_errors,
	);