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Enable post-pass frame index register scavenging for ARM and Thumb2

llvm-svn: 84585
This commit is contained in:
Jim Grosbach 2009-10-20 01:26:58 +00:00
parent 8b2fb5c12a
commit c4acd85bfd
3 changed files with 10 additions and 25 deletions

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@ -785,11 +785,6 @@ void PEI::scavengeFrameVirtualRegs(MachineFunction &Fn) {
if (Reg == 0)
continue;
if (!TargetRegisterInfo::isVirtualRegister(Reg)) {
// If we have an active scavenged register, we shouldn't be
// seeing any references to it.
assert (Reg != CurrentScratchReg
&& "overlapping use of scavenged frame index register!");
// If we have a previous scratch reg, check and see if anything
// here kills whatever value is in there.
if (Reg == PrevScratchReg) {

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@ -934,6 +934,10 @@ bool ARMBaseRegisterInfo::
requiresRegisterScavenging(const MachineFunction &MF) const {
return true;
}
bool ARMBaseRegisterInfo::
requiresFrameIndexScavenging(const MachineFunction &MF) const {
return true;
}
// hasReservedCallFrame - Under normal circumstances, when a frame pointer is
// not required, we reserve argument space for call sites in the function
@ -1010,17 +1014,6 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MBB.erase(I);
}
/// findScratchRegister - Find a 'free' ARM register. If register scavenger
/// is not being used, R12 is available. Otherwise, try for a call-clobbered
/// register first and then a spilled callee-saved register if that fails.
static
unsigned findScratchRegister(RegScavenger *RS, const TargetRegisterClass *RC,
ARMFunctionInfo *AFI) {
unsigned Reg = RS ? RS->FindUnusedReg(RC) : (unsigned) ARM::R12;
assert(!AFI->isThumb1OnlyFunction());
return Reg;
}
unsigned
ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, int *Value,
@ -1075,14 +1068,7 @@ ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
(MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode4) &&
"This code isn't needed if offset already handled!");
// Insert a set of r12 with the full address: r12 = sp + offset
// If the offset we have is too large to fit into the instruction, we need
// to form it with a series of ADDri's. Do this by taking 8-bit chunks
// out of 'Offset'.
unsigned ScratchReg = findScratchRegister(RS, ARM::GPRRegisterClass, AFI);
if (ScratchReg == 0)
// No register is "free". Scavenge a register.
ScratchReg = RS->scavengeRegister(ARM::GPRRegisterClass, II, SPAdj);
unsigned ScratchReg = 0;
int PIdx = MI.findFirstPredOperandIdx();
ARMCC::CondCodes Pred = (PIdx == -1)
? ARMCC::AL : (ARMCC::CondCodes)MI.getOperand(PIdx).getImm();
@ -1091,6 +1077,8 @@ ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
// Must be addrmode4.
MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
else {
ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
*Value = Offset;
if (!AFI->isThumbFunction())
emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
Offset, Pred, PredReg, TII);
@ -1101,7 +1089,7 @@ ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
}
MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);
}
return 0;
return ScratchReg;
}
/// Move iterator pass the next bunch of callee save load / store ops for

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@ -122,6 +122,8 @@ public:
virtual bool requiresRegisterScavenging(const MachineFunction &MF) const;
virtual bool requiresFrameIndexScavenging(const MachineFunction &MF) const;
virtual bool hasReservedCallFrame(MachineFunction &MF) const;
virtual void eliminateCallFramePseudoInstr(MachineFunction &MF,