[PATCH] D151848: [X86, Peephole] Enable FoldImmediate for X86

[Guozhi Wei via Phabricator via llvm-commits]

Carrot added inline comments.


================
Comment at: llvm/test/CodeGen/X86/vector-shuffle-combining-avx512bwvl.ll:176-182
+; X86-NEXT:    xorl %edx, %edx
 ; X86-NEXT:    xorl %eax, %eax
-; X86-NEXT:    testb %al, %al
+; X86-NEXT:    testb %dl, %dl
 ; X86-NEXT:    jne .LBB10_2
 ; X86-NEXT:  # %bb.1: # %if
 ; X86-NEXT:    xorl %eax, %eax
+; X86-NEXT:    xorl %edx, %edx
----------------
MatzeB wrote:
> Odd to see new `xor %edx, %edx` added here. Is that the result of poison or undef values? (in that case "meh" we can ignore it)
This 'xor %edx, %edx' should be the movl instruction in LBB10_2. The first xorl instruction in the function is new. Compare to the source code, %edx and %eax should be variable %i275 and %i277, both are generated from undef value.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D151848/new/

https://reviews.llvm.org/D151848