[flang-commits] [clang] [flang] [llvm] [InstCombine] Canonicalize constant GEPs to i8 source element type (PR #68882)

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Prabhuk wrote:

> I am debugging an assertion failure regression in one of our projects that uses the FlatMap data structure implemented here:
> 
> https://pigweed.googlesource.com/pigweed/pigweed/+/refs/heads/main/pw_containers/public/pw_containers/flat_map.h#180
> 
> The regression was that the `find` function above failed to return the value that's stored in the Map for a valid key.
> 
> A bit of debugging and git bisect of LLVM commits pointed me to this commit [90ba330#diff-0ffb024c6c026c4b93507d08e6d24dccf98980023130781164b71586bc747f2d](https://github.com/llvm/llvm-project/commit/90ba33099cbb17e7c159e9ebc5a512037db99d6d#diff-0ffb024c6c026c4b93507d08e6d24dccf98980023130781164b71586bc747f2d) as the source of failure. Reverting this commit locally fixes the regression.
> 
> I am working on generating a simple reproducer.

This bug is the actual root cause of the failure: https://github.com/llvm/llvm-project/issues/85333


https://github.com/llvm/llvm-project/pull/68882