[all-commits] [llvm/llvm-project] bfa3b6: [InstCombine] Erase attribute lists for simplified...

[Gui Andrade via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: bfa3b627c6832552a7808a9f0f7f9cab61c7ea1a
      https://github.com/llvm/llvm-project/commit/bfa3b627c6832552a7808a9f0f7f9cab61c7ea1a
  Author: Gui Andrade <guiand at google.com>
  Date:   2020-07-13 (Mon, 13 Jul 2020)

  Changed paths:
    M llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
    M llvm/test/Transforms/InstCombine/pow_fp_int.ll
    M llvm/test/Transforms/InstCombine/simplify-libcalls.ll

  Log Message:
  -----------
  [InstCombine] Erase attribute lists for simplified libcalls

Currently, a transformation like pow(2.0, x) -> exp2(x) copies the pow
attribute list verbatim and applies it to exp2. This works out fine
when the attribute list is empty, but when it isn't clang may error due
due to the mismatch.

The source function and destination don't necessarily have anything
to do with one another, attribute-wise. So it makes sense to remove
the attribute lists (this is similar to what IPO does in this
situation).

This was discovered after implementing the `noundef` param attribute.

Differential Revision: https://reviews.llvm.org/D82820