Files
rust/tests/codegen-llvm
Matthias Krüger c772af78e9 Rollup merge of #146732 - durin42:llvm-22-less-assumes, r=nikic
tests: relax expectations after llvm change 902ddda120a5

LLVM 22 is able to drop assumes that seem to not help further optimizations, which actually seems to dramatically _help_ further optimizations in some of our small test cases.

I'm a little unclear how to fix the last failure, in `tests/codegen-llvm/issues/issue-122600-ptr-discriminant-update.rs`:

```
-; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite, inaccessiblemem: write) uwtable
+; Function Attrs: mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(argmem: readwrite, inaccessiblemem: write) uwtable
 define void ``@update(ptr`` noundef captures(none) %s) unnamed_addr #0 {
 start:
-  %_3.sroa.0.0.copyload = load i8, ptr %s, align 1
-  %0 = trunc nuw i8 %_3.sroa.0.0.copyload to i1
-  %1 = xor i1 %0, true
-  tail call void ``@llvm.assume(i1`` %1)
   store i8 1, ptr %s, align 1
   ret void
 }
```

I'm just not conversant enough in LLVM IR to follow the changes here.

``@rustbot`` label llvm-main
r? nikic
2025-09-27 21:25:57 +02:00
..
2025-08-15 16:42:21 +00:00
2025-08-20 16:35:33 +02:00

The files here use the LLVM FileCheck framework, documented at https://llvm.org/docs/CommandGuide/FileCheck.html.

One extension worth noting is the use of revisions as custom prefixes for FileCheck. If your codegen test has different behavior based on the chosen target or different compiler flags that you want to exercise, you can use a revisions annotation, like so:

// revisions: aaa bbb
// [bbb] compile-flags: --flags-for-bbb

After specifying those variations, you can write different expected, or explicitly unexpected output by using <prefix>-SAME: and <prefix>-NOT:, like so:

// CHECK: expected code
// aaa-SAME: emitted-only-for-aaa
// aaa-NOT:                        emitted-only-for-bbb
// bbb-NOT:  emitted-only-for-aaa
// bbb-SAME:                       emitted-only-for-bbb