[all-commits] [llvm/llvm-project] 3706bd: [X86] Remove unnecessary COPY from EmitLoweredCasc...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3706bdad4ae0fe91fbb8bb3e0acc88cf6b13ce56
      https://github.com/llvm/llvm-project/commit/3706bdad4ae0fe91fbb8bb3e0acc88cf6b13ce56
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2022-06-28 (Tue, 28 Jun 2022)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp

  Log Message:
  -----------
  [X86] Remove unnecessary COPY from EmitLoweredCascadedSelect.

I believe we already checked that the destination of the first
CMOV is only used by the second CMOV so I don't think there is any
reason we need the PHI to write the register that was used by the
first CMOV. We can directly use the second CMOV destination and
avoid the copy.

This may be a left over from when the cascaded select handling
was part of the main algorithm before it was refactored in D35685.

Reviewed By: pengfei

Differential Revision: https://reviews.llvm.org/D128124