[PATCH] D54095: [X86] X86DAGToDAGISel::matchBitExtract(): extract 'lshr' from `X`

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: test/CodeGen/X86/extract-bits.ll:54
 ; X86-BMI1NOTBM-NEXT:    shll $8, %eax
-; X86-BMI1NOTBM-NEXT:    bextrl %eax, %edx, %eax
+; X86-BMI1NOTBM-NEXT:    orl %ecx, %eax
+; X86-BMI1NOTBM-NEXT:    bextrl %eax, {{[0-9]+}}(%esp), %eax
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This doesn't look its zero-extending properly - the upper bits contents of RAX/RCX will both contain garbage as movb doesn't zero-extend.


Repository:
  rL LLVM

https://reviews.llvm.org/D54095