[all-commits] [llvm/llvm-project] ba6a10: [MachineCopyPropagation] In isNopCopy, check the d...

[topperc via All-commits]

  Branch: refs/heads/release/11.x
  Home:   https://github.com/llvm/llvm-project
  Commit: ba6a10d87f57b78303555028f92add22918b3bcb
      https://github.com/llvm/llvm-project/commit/ba6a10d87f57b78303555028f92add22918b3bcb
  Author: Craig Topper <craig.topper at intel.com>
  Date:   2020-09-07 (Mon, 07 Sep 2020)

  Changed paths:
    M llvm/lib/CodeGen/MachineCopyPropagation.cpp
    A llvm/test/CodeGen/X86/machine-cp-mask-reg.mir

  Log Message:
  -----------
  [MachineCopyPropagation] In isNopCopy, check the destination registers match in addition to the source registers.

Previously if the source match we asserted that the destination
matched. But GPR <-> mask register copies on X86 can violate this
since we use the same K-registers for multiple sizes.

Fixes this ISPC issue https://github.com/ispc/ispc/issues/1851

Differential Revision: https://reviews.llvm.org/D86507

(cherry picked from commit 4783e2c9c603ed6aeacc76bb1177056a9d307bd1)