Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust by sgasho · Pull Request #156777 · rust-lang/rust

sgasho · 2026-05-20T15:05:35Z

Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust
Change some llvm ir check in codegen_llvm/autodiff tests

sgasho · 2026-06-12T14:47:53Z

I tested this PR still works after enzyme submodule update: #157716

ZuseZ4 · 2026-06-15T07:07:28Z

I think I've seen some of these changes before, so my concern is that either we continue to make the tests increasingly weaker, or we'll keep swapping back and forth between different outputs.
In the past, I added the noPostOpt flag, which made it a little better, but since the output still changed, we should find a more robust solution before putting it in CI.
Can you have a look at the -C passes=val -- a list of extra LLVM passes to run (space separated) flag, as well as some of the enzyme tests which run extra opts after enzyme?
https://github.com/EnzymeAD/Enzyme/blob/c96508349d9f121957292308c646b4a1fd53c507/enzyme/test/Enzyme/ReverseMode/add.ll#L2

We probably want to remove -Zautodiff=NoPostopt and replace it with -Zautodiff=Passes=... or something like that.
There is a -Zoffload=Host=path flag, which is also nested as an example.
The idea is that not setting the flag would result in the current behavior (full O3 after Enzyme), setting it to "" would be equal to the current NoPostOpt flag (which can then be removed) and by setting anything else we can specify the actual passes to run, similar to Enzyme.

sgasho · 2026-06-20T11:52:14Z

Thanks!
I added the autodiff_post_passes flag. I thought it would be convenient to pass LLVM passes in the same format LLVM expects, comma separated. If we add a nested option like -Zautodiff=Passes=..., we would need special parsing or escaping, since -Zautodiff options are also separated by commas.

rustbot · 2026-06-29T12:26:08Z

This PR was rebased onto a different main 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.

ZuseZ4 · 2026-07-02T15:08:26Z

lgtm, but can you clean up the story a bit? Maybe make one commit first to introduce the infra, and then another one to update the test.
@bors delegate
with updated history and when ci is green.

rust-bors · 2026-07-02T15:08:30Z

✌️ @sgasho, you can now approve this pull request!

If @ZuseZ4 told you to "r=me" after making some further change, then please make that change and post @bors r=ZuseZ4.

View changes since this delegation.

…er enzyme

sgasho · 2026-07-03T00:50:32Z

@bors r=ZuseZ4

rust-bors · 2026-07-03T00:50:35Z

📌 Commit 2a9e45d has been approved by ZuseZ4

It is now in the queue for this repository.

🌲 The tree is currently closed for pull requests below priority 10. This pull request will be tested once the tree is reopened.

@ZuseZ4

…iff-2, r=ZuseZ4 Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust * Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust * Change some llvm ir check in codegen_llvm/autodiff tests r? @ZuseZ4

Rollup of 18 pull requests Successful merges: - #158692 (Add release notes for 1.96.1) - #134021 (Implement `IntoIterator` for `[&[mut]] Box<[T; N], A>`) - #152860 (Port the `without_debuginfo` test from `backtrace-rs` to the testsuite) - #155932 (MIR Call terminator: evaluate destination place before arguments) - #156777 (Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust) - #157151 (JSON target specs: remove 'x86-softfloat' compatibility alias) - #157835 (expand free alias types in the auto-trait orphan check) - #158377 (add `-Zforce-intrinsic-fallback` flag) - #158434 (delegation: refactor AST -> HIR lowering) - #158552 (make some tidy errors around python easier to understand) - #158624 (borrowck: Introduce BlameConstraint::to_obligation_cause_from_path()) - #158704 (Optimize `ArrayChunks::try_rfold` with `DoubleEndedIterator::next_chunk_back`) - #158711 (library: Comment on libtest's dicey internal soundness) - #158539 (Move `SizeHint` and `IoHandle` to `core::io`) - #158659 (refactor the normalization in `coerce_shared_info`) - #158689 (resolver: don't use `Finalize` when resolving visibilities during AST expansion) - #158698 (Update TypeVisitable implementation) - #158706 (Tweaks to MIR building scope API)

@ZuseZ4

…iff-2, r=ZuseZ4 Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust * Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust * Change some llvm ir check in codegen_llvm/autodiff tests r? @ZuseZ4

…uwer Rollup of 20 pull requests Successful merges: - #158692 (Add release notes for 1.96.1) - #134021 (Implement `IntoIterator` for `[&[mut]] Box<[T; N], A>`) - #155932 (MIR Call terminator: evaluate destination place before arguments) - #155989 (Update `transmute_copy` to ub_checks and `?Sized`) - #156777 (Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust) - #157151 (JSON target specs: remove 'x86-softfloat' compatibility alias) - #157835 (expand free alias types in the auto-trait orphan check) - #157857 (Stabilize `#[my_macro] mod foo;` (part of `proc_macro_hygiene`)) - #158377 (add `-Zforce-intrinsic-fallback` flag) - #158434 (delegation: refactor AST -> HIR lowering) - #158552 (make some tidy errors around python easier to understand) - #158624 (borrowck: Introduce BlameConstraint::to_obligation_cause_from_path()) - #158704 (Optimize `ArrayChunks::try_rfold` with `DoubleEndedIterator::next_chunk_back`) - #158711 (library: Comment on libtest's dicey internal soundness) - #158751 (rustdoc: Fix crash when trying to inline foreign item which cannot have attributes) - #158539 (Move `SizeHint` and `IoHandle` to `core::io`) - #158659 (refactor the normalization in `coerce_shared_info`) - #158689 (resolver: don't use `Finalize` when resolving visibilities during AST expansion) - #158698 (Update TypeVisitable implementation) - #158706 (Tweaks to MIR building scope API)

…uwer Rollup of 19 pull requests Successful merges: - #158692 (Add release notes for 1.96.1) - #134021 (Implement `IntoIterator` for `[&[mut]] Box<[T; N], A>`) - #155932 (MIR Call terminator: evaluate destination place before arguments) - #155989 (Update `transmute_copy` to ub_checks and `?Sized`) - #156777 (Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust) - #157151 (JSON target specs: remove 'x86-softfloat' compatibility alias) - #157835 (expand free alias types in the auto-trait orphan check) - #157857 (Stabilize `#[my_macro] mod foo;` (part of `proc_macro_hygiene`)) - #158434 (delegation: refactor AST -> HIR lowering) - #158552 (make some tidy errors around python easier to understand) - #158624 (borrowck: Introduce BlameConstraint::to_obligation_cause_from_path()) - #158704 (Optimize `ArrayChunks::try_rfold` with `DoubleEndedIterator::next_chunk_back`) - #158711 (library: Comment on libtest's dicey internal soundness) - #158751 (rustdoc: Fix crash when trying to inline foreign item which cannot have attributes) - #158539 (Move `SizeHint` and `IoHandle` to `core::io`) - #158659 (refactor the normalization in `coerce_shared_info`) - #158689 (resolver: don't use `Finalize` when resolving visibilities during AST expansion) - #158698 (Update TypeVisitable implementation) - #158706 (Tweaks to MIR building scope API)

@ZuseZ4

Rollup merge of #156777 - sgasho:test-fix-codegen-llvm-autodiff-2, r=ZuseZ4 Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust * Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust * Change some llvm ir check in codegen_llvm/autodiff tests r? @ZuseZ4

rustbot assigned ZuseZ4 May 20, 2026

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 May 20, 2026

rust-cloud-vms Bot force-pushed the test-fix-codegen-llvm-autodiff-2 branch from 64371d7 to 0da69f6 Compare June 12, 2026 14:47

rustbot added the A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. label Jun 20, 2026

sgasho changed the title ~~Fix LLVM IR expectations for the autodiff abi_handling tests~~ Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust Jun 20, 2026

sgasho force-pushed the test-fix-codegen-llvm-autodiff-2 branch from 04bcb8e to 08f1ff1 Compare June 20, 2026 11:43

ZuseZ4 reviewed Jun 24, 2026

View reviewed changes

Comment thread tests/codegen-llvm/autodiff/batched.rs Outdated

Comment thread compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp Outdated

sgasho force-pushed the test-fix-codegen-llvm-autodiff-2 branch from a7089cb to bd0eab1 Compare June 29, 2026 12:26

sgasho requested a review from ZuseZ4 June 29, 2026 13:44

sgasho added 2 commits July 3, 2026 00:43

Add -Zautodiff_post_passes flag to limit which llvm passes to run aft…

d7e4edd

…er enzyme

Update LLVM IR checks in codegen-llvm/autodiff tests

2a9e45d

sgasho force-pushed the test-fix-codegen-llvm-autodiff-2 branch from 85ca87b to 2a9e45d Compare July 2, 2026 15:45

rust-bors Bot 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 Jul 3, 2026

jhpratt mentioned this pull request Jul 3, 2026

Rollup of 18 pull requests #158753

Closed

JonathanBrouwer mentioned this pull request Jul 5, 2026

Rollup of 20 pull requests #158798

Closed

JonathanBrouwer mentioned this pull request Jul 5, 2026

Rollup of 19 pull requests #158811

Merged

rust-bors Bot merged commit 2085491 into rust-lang:main Jul 5, 2026
13 checks passed

rustbot added this to the 1.98.0 milestone Jul 5, 2026

theemathas modified the milestones: 1.98.0, 1.99.0 Jul 6, 2026

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Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust#156777

Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust#156777
rust-bors[bot] merged 2 commits into
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sgasho:test-fix-codegen-llvm-autodiff-2

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