[PATCH] D86260: [CodeGen] Postprocess PHI nodes for callbr

Nick Desaulniers via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Thu Aug 20 11:18:04 PDT 2020


nickdesaulniers added inline comments.


================
Comment at: llvm/test/CodeGen/X86/callbr-asm-phi-nodes.ll:9
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    movl %gs:0, %eax
+; CHECK-NEXT:    #APP
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craig.topper wrote:
> nickdesaulniers wrote:
> > What was the input C program, was it precisely https://godbolt.org/z/zqK1K7 from https://bugs.llvm.org/show_bug.cgi?id=47242.  If so, this `mov` into `%eax` looks problematic; it gets overwritten on both branches of the INLINEASM_BR, and looks like a dead store to me.
> I think its there because the value of @var is an input to the inline asm. But the asm doesn't use it?
ah, I think removing `thread_local` from `@var` may remove this noise from the test case.


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D86260/new/

https://reviews.llvm.org/D86260



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