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Be over-conservative: scan for all used virtual registers and calculate maximal stack alignment in assumption, that there will be spill of vector register.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50167 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov 2008-04-23 18:23:30 +00:00
parent 856914fe00
commit d52bdaff0c
2 changed files with 11 additions and 2 deletions
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11
lib/Target/X86/X86RegisterInfo.cpp
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@ -1121,11 +1121,18 @@ namespace {
virtual bool runOnMachineFunction(MachineFunction &MF) {
MachineFrameInfo *FFI = MF.getFrameInfo();
MachineRegisterInfo &RI = MF.getRegInfo();
// Calculate and set max stack object alignment early, so we can decide
// whether we will need stack realignment (and thus FP).
// Calculate max stack alignment of all already allocated stack objects.
unsigned MaxAlign = calculateMaxStackAlignment(FFI);
// Be over-conservative: scan over all vreg defs and find, whether vector
// registers are used. If yes - there is probability, that vector register
// will be spilled and thus stack needs to be aligned properly.
for (unsigned RegNum = TargetRegisterInfo::FirstVirtualRegister;
RegNum < RI.getLastVirtReg(); ++RegNum)
MaxAlign = std::max(MaxAlign, RI.getRegClass(RegNum)->getAlignment());
FFI->setMaxAlignment(MaxAlign);
return false;

2
lib/Target/X86/X86TargetMachine.cpp
View File

@ -162,6 +162,8 @@ bool X86TargetMachine::addInstSelector(PassManagerBase &PM, bool Fast) {
}
bool X86TargetMachine::addPreRegAlloc(PassManagerBase &PM, bool Fast) {
// Calculate and set max stack object alignment early, so we can decide
// whether we will need stack realignment (and thus FP).
PM.add(createX86MaxStackAlignmentCalculatorPass());
return false; // -print-machineinstr shouldn't print after this.
}