Do not compute optimized MIR if code does not type-check. #147092

cjgillot · 2025-09-27T13:47:09Z

Since #128612, we compute optimized MIR when -Zvalidate-mir is present.

This is done as part of required analyses, even if type-checking fails. This causes ICEs, as most of the mir-opt pipeline expects well-formed code.

Fixes #129095
Fixes #134174
Fixes #134654
Fixes #135570
Fixes #136381
Fixes #137468
Fixes #144491
Fixes #147011

This does not fix issue #137190, as it ICEs without -Zvalidate-mir.

r? @compiler-errors

rustbot · 2025-09-27T13:47:12Z

This PR changes a file inside tests/crashes. If a crash was fixed, please move into the corresponding ui subdir and add 'Fixes #' to the PR description to autoclose the issue upon merge.

rustbot · 2025-09-27T13:47:13Z

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r=me when green

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cjgillot · 2025-09-27T16:07:17Z

@bors r=compiler-errors rollup

bors · 2025-09-27T16:07:19Z

📌 Commit c6657be has been approved by compiler-errors

It is now in the queue for this repository.

…iler-errors Do not compute optimized MIR if code does not type-check. Since rust-lang#128612, we compute optimized MIR when `-Zvalidate-mir` is present. This is done as part of required analyses, even if type-checking fails. This causes ICEs, as most of the mir-opt pipeline expects well-formed code. Fixes rust-lang#129095 Fixes rust-lang#134174 Fixes rust-lang#134654 Fixes rust-lang#136381 Fixes rust-lang#137468 Fixes rust-lang#144491 Fixes rust-lang#147011 This does not fix issue rust-lang#137190, as it ICEs without `-Zvalidate-mir`. r? `@compiler-errors`

Rollup of 16 pull requests Successful merges: - #142139 (Include additional hashes in src/stage0) - #146745 (Clarified error note for usize range matching) - #146763 (cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 5)) - #146788 (chore: removes deprecated discord.) - #146942 ([rustdoc] Finish getting rid of usages `write_str`) - #147002 (rustdoc-search: stringdex update with more packing) - #147061 (fix rebasing cycle heads when not reaching a fixpoint) - #147066 (Fix tracking issue number for feature(macro_attr)) - #147081 (doc: fix a typo in platform-support.md) - #147082 (formatting_options: fix alternate docs 0b/0o mixup) - #147086 (compiletest: Use `PanicHookInfo::payload_as_str` now that it's stable in beta) - #147092 (Do not compute optimized MIR if code does not type-check.) - #147093 (redox: switch to colon as path separator) - #147095 (Library: Remove remaining private `#[repr]` workarounds) - #147098 (Add auto extra-checks in pre-push hook) - #147110 (Fix typo) r? `@ghost` `@rustbot` modify labels: rollup

Zalathar · 2025-09-28T07:21:34Z

Probably failed in rollup due to crash test not crashing: #147114 (comment)

@bors r-

Zalathar · 2025-09-28T07:26:21Z

(Bisecting the rollup now; I'll reapprove if my guess was wrong.)

Zalathar · 2025-09-28T08:03:38Z

OK I can confirm that this PR also fixes tests/crashes/134654.rs and tests/crashes/135570.rs.

Tracking this down was made much harder by the tests being marked //@ only-x86_64 for seemingly no reason.

rustbot · 2025-09-28T15:59:31Z

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

cjgillot · 2025-09-28T16:37:06Z

@bors r=compiler-errors rollup

bors · 2025-09-28T16:37:09Z

📌 Commit 7a7cb05 has been approved by compiler-errors

It is now in the queue for this repository.

…iler-errors Do not compute optimized MIR if code does not type-check. Since rust-lang#128612, we compute optimized MIR when `-Zvalidate-mir` is present. This is done as part of required analyses, even if type-checking fails. This causes ICEs, as most of the mir-opt pipeline expects well-formed code. Fixes rust-lang#129095 Fixes rust-lang#134174 Fixes rust-lang#134654 Fixes rust-lang#135570 Fixes rust-lang#136381 Fixes rust-lang#137468 Fixes rust-lang#144491 Fixes rust-lang#147011 This does not fix issue rust-lang#137190, as it ICEs without `-Zvalidate-mir`. r? `@compiler-errors`

Rollup of 6 pull requests Successful merges: - #133477 (Detect tuple structs that are unconstructable due to re-export) - #140916 (Fix unuseful span in type error in some format_args!() invocations) - #146979 (constify Default on Nanoseconds) - #147090 (Skip stack overflow handler for panic=immediate-abort) - #147092 (Do not compute optimized MIR if code does not type-check.) - #147127 (Add a leading dash to linker plugin arguments in the gcc codegen) r? `@ghost` `@rustbot` modify labels: rollup

Rollup of 7 pull requests Successful merges: - #133477 (Detect tuple structs that are unconstructable due to re-export) - #146929 (compiletest: Remove old-output-capture and become a stage0 bootstrap tool) - #146979 (constify Default on Nanoseconds) - #147092 (Do not compute optimized MIR if code does not type-check.) - #147112 (all 48 keywords in just 300 characters) - #147122 (Fix some crash-test directives) - #147127 (Add a leading dash to linker plugin arguments in the gcc codegen) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #147092 - cjgillot:late-validate-mir, r=compiler-errors Do not compute optimized MIR if code does not type-check. Since #128612, we compute optimized MIR when `-Zvalidate-mir` is present. This is done as part of required analyses, even if type-checking fails. This causes ICEs, as most of the mir-opt pipeline expects well-formed code. Fixes #129095 Fixes #134174 Fixes #134654 Fixes #135570 Fixes #136381 Fixes #137468 Fixes #144491 Fixes #147011 This does not fix issue #137190, as it ICEs without `-Zvalidate-mir`. r? ``@compiler-errors``

Zalathar · 2025-09-29T11:05:17Z

@rust-timer build 5e08e7f

rust-timer · 2025-09-29T13:26:15Z

Finished benchmarking commit (5e08e7f): comparison URL.

Overall result: ❌ regressions - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	3.0%	[3.0%, 3.0%]	1
Regressions ❌ (secondary)	0.3%	[0.3%, 0.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.0%	[3.0%, 3.0%]	1

Max RSS (memory usage)

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

Cycles

Results (primary 2.3%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	2.3%	[1.9%, 2.7%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.3%	[1.9%, 2.7%]	2

Binary size

Results (primary 1.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.1%	[1.1%, 1.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.1%	[1.1%, 1.1%]	1

Bootstrap: 469.945s -> 471.627s (0.36%)
Artifact size: 387.67 MiB -> 387.67 MiB (0.00%)

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 Sep 27, 2025

rustbot assigned compiler-errors Sep 27, 2025

compiler-errors approved these changes Sep 27, 2025

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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 Sep 27, 2025

Zalathar mentioned this pull request Sep 28, 2025

Rollup of 16 pull requests #147114

Closed

bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Sep 28, 2025

Do not validate MIR if code does not type-check.

7a7cb05

cjgillot force-pushed the late-validate-mir branch from c6657be to 7a7cb05 Compare September 28, 2025 15:59

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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 28, 2025

Zalathar mentioned this pull request Sep 29, 2025

Rollup of 6 pull requests #147139

Closed

Zalathar mentioned this pull request Sep 29, 2025

Rollup of 7 pull requests #147140

Merged

bors merged commit 01b172e into rust-lang:master Sep 29, 2025
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rustbot added this to the 1.92.0 milestone Sep 29, 2025

cjgillot deleted the late-validate-mir branch September 29, 2025 10:26

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Do not compute optimized MIR if code does not type-check. #147092

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Overall result: ❌ regressions - please read the text below

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