| Issue |
174045
|
| Summary |
[InstSimplify] Folds vector pointer `select (icmp eq <N x ptr>)` to operand and loses provenance
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
cardigan1008
|
Instsimplify can fold:
```llvm
%cmp = icmp eq <2 x ptr> %a, %b
%sel = select <2 x i1> %cmp, <2 x ptr> %a, %b
```
to `ret <2 x ptr> %b`, which is not always valid for pointers. Even if `%a[0]` and `%b[0]` have the same address , they might have different provenance, so selecting `%a[0]` is not equivalent to returning `%b[0]`.
Alive2 proof: https://alive2.llvm.org/ce/z/JxDjAx
Exposed from https://github.com/llvm/llvm-project/commit/1af627b592dd15bbe58136f902ced46251fc344d, cc @dtcxzyw
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