[all-commits] [llvm/llvm-project] 04013a: [X86] Fix two places that appear to misuse peekThr...

[topperc via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 04013a07ac3b67eb176ddfd1ddaeda41415c038f
      https://github.com/llvm/llvm-project/commit/04013a07ac3b67eb176ddfd1ddaeda41415c038f
  Author: Craig Topper <craig.topper at intel.com>
  Date:   2020-07-12 (Sun, 12 Jul 2020)

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

  Log Message:
  -----------
  [X86] Fix two places that appear to misuse peekThroughOneUseBitcasts

peekThroughOneUseBitcasts checks the use count of the operand of the bitcast. Not the bitcast itself. So I think that means we need to do any outside haseOneUse checks before calling the function not after.

I was working on another patch where I misused the function and did a very quick audit to see if I there were other similar mistakes.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D83598


  Commit: f8f007e378e1ed84fadf281f05166a4463a79316
      https://github.com/llvm/llvm-project/commit/f8f007e378e1ed84fadf281f05166a4463a79316
  Author: Craig Topper <craig.topper at intel.com>
  Date:   2020-07-12 (Sun, 12 Jul 2020)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/vector-trunc.ll

  Log Message:
  -----------
  [X86] Consistently use 128 as the PSHUFB/VPPERM index for zero

Bit 7 of the index controls zeroing, the other bits are ignored when bit 7 is set. Shuffle lowering was using 128 and shuffle combining was using 255. Seems like we should be consistent.

This patch changes shuffle combining to use 128 to match lowering.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D83587


Compare: https://github.com/llvm/llvm-project/compare/65dc97b79eb1...f8f007e378e1