[PATCH] D110869: [X86] Implement -fzero-call-used-regs option

Mon Jan 31 16:03:24 PST 2022

nickdesaulniers added inline comments.

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Comment at: llvm/lib/Target/X86/X86RegisterInfo.cpp:621

+BitVector X86RegisterInfo::getArgumentRegs(const MachineFunction &MF) const {
+  const X86Subtarget &Subtarget = MF.getSubtarget<X86Subtarget>();
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nickdesaulniers wrote:
> pengfei wrote:
> > Can we get this info from calling conversion?
> > Different calling conversions may use different argument registers.
> when working on the ppc issue recently (https://reviews.llvm.org/D116424), I recall there being an existing check for whether a register was callee saved.
> 
> RegisterClassInfo::getLastCalleeSavedAlias
> 
> Can that be reused here or in any of the below?
> 
> Do we need to zero stack slots when arguments are passed on the stack (after exhausting the "argument registers?"
oops, my last comment here was a draft that I meant to delete before submitting all my previous comments. Feel free to ignore.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110869/new/

https://reviews.llvm.org/D110869