[all-commits] [llvm/llvm-project] c85eda: [AMDGPU] fix copies between 32 and 16 bit

[Stanislav Mekhanoshin via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: c85eda74b8581ee068431b73937f1aeeed455698
      https://github.com/llvm/llvm-project/commit/c85eda74b8581ee068431b73937f1aeeed455698
  Author: Stanislav Mekhanoshin <Stanislav.Mekhanoshin at amd.com>
  Date:   2020-05-04 (Mon, 04 May 2020)

  Changed paths:
    M llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
    A llvm/test/CodeGen/AMDGPU/lo16-32bit-physreg-copy.mir

  Log Message:
  -----------
  [AMDGPU] fix copies between 32 and 16 bit

This a hack to fix illegal 32 to 16 bit copies.
The problem is when we make 16 bit subregs legal it creates
a huge amount of failures which can only be resolved at once
without a temporary hack like this.

The next step is to change operands, instruction definitions
and patterns until this hack is not needed.

Differential Revision: https://reviews.llvm.org/D79119