Use the "isCompare" machine instruction attribute instead of calling the

relatively expensive comparison analyzer on each instruction. Also rename the
comparison analyzer method to something more in line with what it actually does.

This pass is will eventually be folded into the Machine CSE pass.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110539 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2010-08-08 05:04:59 +00:00
parent be04fdeb6c
commit c98af3370f
5 changed files with 22 additions and 21 deletions

View File

@ -577,17 +577,17 @@ public:
virtual ScheduleHazardRecognizer*
CreateTargetPostRAHazardRecognizer(const InstrItineraryData&) const = 0;
/// isCompareInstr - If the machine instruction is a comparison instruction,
/// then return true. Also return the source register in SrcReg and the value
/// it compares against in CmpValue.
virtual bool isCompareInstr(const MachineInstr *MI,
/// AnalyzeCompare - For a comparison instruction, return the source register
/// in SrcReg and the value it compares against in CmpValue. Return true if
/// the comparison instruction can be analyzed.
virtual bool AnalyzeCompare(const MachineInstr *MI,
unsigned &SrcReg, int &CmpValue) const {
return false;
}
/// convertToSetZeroFlag - Convert the instruction to set the zero flag so
/// ConvertToSetZeroFlag - Convert the instruction to set the zero flag so
/// that we can remove a "comparison with zero".
virtual bool convertToSetZeroFlag(MachineInstr *Instr,
virtual bool ConvertToSetZeroFlag(MachineInstr *Instr,
MachineInstr *CmpInstr) const {
return false;
}

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@ -72,9 +72,8 @@ bool OptimizeCmps::OptimizeCmpInstr(MachineInstr *MI, MachineBasicBlock *MBB) {
// physical register, we can try to optimize it.
unsigned SrcReg;
int CmpValue;
if (!TII->isCompareInstr(MI, SrcReg, CmpValue) ||
TargetRegisterInfo::isPhysicalRegister(SrcReg) ||
CmpValue != 0)
if (!TII->AnalyzeCompare(MI, SrcReg, CmpValue) ||
TargetRegisterInfo::isPhysicalRegister(SrcReg) || CmpValue != 0)
return false;
MachineRegisterInfo::def_iterator DI = MRI->def_begin(SrcReg);
@ -83,7 +82,7 @@ bool OptimizeCmps::OptimizeCmpInstr(MachineInstr *MI, MachineBasicBlock *MBB) {
return false;
// Attempt to convert the defining instruction to set the "zero" flag.
if (TII->convertToSetZeroFlag(&*DI, MI)) {
if (TII->ConvertToSetZeroFlag(&*DI, MI)) {
++NumEliminated;
return true;
}
@ -104,7 +103,8 @@ bool OptimizeCmps::runOnMachineFunction(MachineFunction &MF) {
for (MachineBasicBlock::iterator
MII = MBB->begin(), ME = MBB->end(); MII != ME; ) {
MachineInstr *MI = &*MII++;
Changed |= OptimizeCmpInstr(MI, MBB);
if (MI->getDesc().isCompare())
Changed |= OptimizeCmpInstr(MI, MBB);
}
}

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@ -1355,7 +1355,7 @@ bool llvm::rewriteARMFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
}
bool ARMBaseInstrInfo::
isCompareInstr(const MachineInstr *MI, unsigned &SrcReg, int &CmpValue) const {
AnalyzeCompare(const MachineInstr *MI, unsigned &SrcReg, int &CmpValue) const {
switch (MI->getOpcode()) {
default: break;
case ARM::t2CMPri:
@ -1368,10 +1368,10 @@ isCompareInstr(const MachineInstr *MI, unsigned &SrcReg, int &CmpValue) const {
return false;
}
/// convertToSetZeroFlag - Convert the instruction to set the "zero" flag so
/// ConvertToSetZeroFlag - Convert the instruction to set the "zero" flag so
/// that we can remove a "comparison with zero".
bool ARMBaseInstrInfo::
convertToSetZeroFlag(MachineInstr *MI, MachineInstr *CmpInstr) const {
ConvertToSetZeroFlag(MachineInstr *MI, MachineInstr *CmpInstr) const {
// Conservatively refuse to convert an instruction which isn't in the same BB
// as the comparison.
if (MI->getParent() != CmpInstr->getParent())

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@ -337,15 +337,15 @@ public:
return NumInstrs && NumInstrs == 1;
}
/// isCompareInstr - If the machine instruction is a comparison instruction,
/// then return true. Also return the source register in SrcReg and the value
/// it compares against in CmpValue.
virtual bool isCompareInstr(const MachineInstr *MI, unsigned &SrcReg,
/// AnalyzeCompare - For a comparison instruction, return the source register
/// in SrcReg and the value it compares against in CmpValue. Return true if
/// the comparison instruction can be analyzed.
virtual bool AnalyzeCompare(const MachineInstr *MI, unsigned &SrcReg,
int &CmpValue) const;
/// convertToSetZeroFlag - Convert the instruction to set the zero flag so
/// ConvertToSetZeroFlag - Convert the instruction to set the zero flag so
/// that we can remove a "comparison with zero".
virtual bool convertToSetZeroFlag(MachineInstr *Instr,
virtual bool ConvertToSetZeroFlag(MachineInstr *Instr,
MachineInstr *CmpInstr) const;
};

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@ -2155,11 +2155,12 @@ def : T2Pat<(or (and rGPR:$src1, 0xFFFF0000),
//===----------------------------------------------------------------------===//
// Comparison Instructions...
//
let isCompare = 1 in {
defm t2CMP : T2I_cmp_irs<0b1101, "cmp",
BinOpFrag<(ARMcmp node:$LHS, node:$RHS)>>;
defm t2CMPz : T2I_cmp_irs<0b1101, "cmp",
BinOpFrag<(ARMcmpZ node:$LHS, node:$RHS)>>;
}
//FIXME: Disable CMN, as CCodes are backwards from compare expectations
// Compare-to-zero still works out, just not the relationals