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Mark the x86 fp stack registers as "reserved". This tells LiveVariables

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and the RegisterScavenger not to expect traditional liveness 
techniques are applicable to these registers, since we don't fully
modify the effects of push and pop after stackification.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61179 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2008-12-18 01:05:09 +00:00
parent 12b882cf53
commit a32b7ac86f
1 changed files with 14 additions and 0 deletions
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14
lib/Target/X86/X86RegisterInfo.cpp
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@ -263,16 +263,30 @@ X86RegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
// Set the stack-pointer register and its aliases as reserved.
Reserved.set(X86::RSP);
Reserved.set(X86::ESP);
Reserved.set(X86::SP);
Reserved.set(X86::SPL);
// Set the frame-pointer register and its aliases as reserved if needed.
if (hasFP(MF)) {
Reserved.set(X86::RBP);
Reserved.set(X86::EBP);
Reserved.set(X86::BP);
Reserved.set(X86::BPL);
}
// Mark the x87 stack registers as reserved, since they don't
// behave normally with respect to liveness. We don't fully
// model the effects of x87 stack pushes and pops after
// stackification.
Reserved.set(X86::ST0);
Reserved.set(X86::ST1);
Reserved.set(X86::ST2);
Reserved.set(X86::ST3);
Reserved.set(X86::ST4);
Reserved.set(X86::ST5);
Reserved.set(X86::ST6);
Reserved.set(X86::ST7);
return Reserved;
}