//===----------------------------------------------------------------------===//
#include "AArch64InstrInfo.h"
+#include "AArch64MachineCombinerPattern.h"
#include "AArch64Subtarget.h"
#include "MCTargetDesc/AArch64AddressingModes.h"
-#include "AArch64MachineCombinerPattern.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineMemOperand.h"
BuildMI(&MBB, DL, get(AArch64::Bcc)).addImm(Cond[0].getImm()).addMBB(TBB);
} else {
// Folded compare-and-branch
+ // Note that we use addOperand instead of addReg to keep the flags.
const MachineInstrBuilder MIB =
- BuildMI(&MBB, DL, get(Cond[1].getImm())).addReg(Cond[2].getReg());
+ BuildMI(&MBB, DL, get(Cond[1].getImm())).addOperand(Cond[2]);
if (Cond.size() > 3)
MIB.addImm(Cond[3].getImm());
MIB.addMBB(TBB);
assert(MBB && "Can't get MachineBasicBlock here");
MachineFunction *MF = MBB->getParent();
assert(MF && "Can't get MachineFunction here");
- const TargetMachine *TM = &MF->getTarget();
- const TargetInstrInfo *TII = TM->getSubtargetImpl()->getInstrInfo();
- const TargetRegisterInfo *TRI = TM->getSubtargetImpl()->getRegisterInfo();
+ const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
+ const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
MachineRegisterInfo *MRI = &MF->getRegInfo();
for (unsigned OpIdx = 0, EndIdx = Instr->getNumOperands(); OpIdx < EndIdx;
return true;
}
-/// convertFlagSettingOpcode - return opcode that does not
-/// set flags when possible. The caller is responsible to do
-/// the actual substitution and legality checking.
-static unsigned convertFlagSettingOpcode(MachineInstr *MI) {
- unsigned NewOpc;
- switch (MI->getOpcode()) {
- default:
- return false;
- case AArch64::ADDSWrr: NewOpc = AArch64::ADDWrr; break;
- case AArch64::ADDSWri: NewOpc = AArch64::ADDWri; break;
- case AArch64::ADDSWrs: NewOpc = AArch64::ADDWrs; break;
- case AArch64::ADDSWrx: NewOpc = AArch64::ADDWrx; break;
- case AArch64::ADDSXrr: NewOpc = AArch64::ADDXrr; break;
- case AArch64::ADDSXri: NewOpc = AArch64::ADDXri; break;
- case AArch64::ADDSXrs: NewOpc = AArch64::ADDXrs; break;
- case AArch64::ADDSXrx: NewOpc = AArch64::ADDXrx; break;
- case AArch64::SUBSWrr: NewOpc = AArch64::SUBWrr; break;
- case AArch64::SUBSWri: NewOpc = AArch64::SUBWri; break;
- case AArch64::SUBSWrs: NewOpc = AArch64::SUBWrs; break;
- case AArch64::SUBSWrx: NewOpc = AArch64::SUBWrx; break;
- case AArch64::SUBSXrr: NewOpc = AArch64::SUBXrr; break;
- case AArch64::SUBSXri: NewOpc = AArch64::SUBXri; break;
- case AArch64::SUBSXrs: NewOpc = AArch64::SUBXrs; break;
- case AArch64::SUBSXrx: NewOpc = AArch64::SUBXrx; break;
- }
- return NewOpc;
+/// \brief Return the opcode that does not set flags when possible - otherwise
+/// return the original opcode. The caller is responsible to do the actual
+/// substitution and legality checking.
+static unsigned convertFlagSettingOpcode(const MachineInstr *MI) {
+ // Don't convert all compare instructions, because for some the zero register
+ // encoding becomes the sp register.
+ bool MIDefinesZeroReg = false;
+ if (MI->definesRegister(AArch64::WZR) || MI->definesRegister(AArch64::XZR))
+ MIDefinesZeroReg = true;
+
+ switch (MI->getOpcode()) {
+ default:
+ return MI->getOpcode();
+ case AArch64::ADDSWrr:
+ return AArch64::ADDWrr;
+ case AArch64::ADDSWri:
+ return MIDefinesZeroReg ? AArch64::ADDSWri : AArch64::ADDWri;
+ case AArch64::ADDSWrs:
+ return MIDefinesZeroReg ? AArch64::ADDSWrs : AArch64::ADDWrs;
+ case AArch64::ADDSWrx:
+ return AArch64::ADDWrx;
+ case AArch64::ADDSXrr:
+ return AArch64::ADDXrr;
+ case AArch64::ADDSXri:
+ return MIDefinesZeroReg ? AArch64::ADDSXri : AArch64::ADDXri;
+ case AArch64::ADDSXrs:
+ return MIDefinesZeroReg ? AArch64::ADDSXrs : AArch64::ADDXrs;
+ case AArch64::ADDSXrx:
+ return AArch64::ADDXrx;
+ case AArch64::SUBSWrr:
+ return AArch64::SUBWrr;
+ case AArch64::SUBSWri:
+ return MIDefinesZeroReg ? AArch64::SUBSWri : AArch64::SUBWri;
+ case AArch64::SUBSWrs:
+ return MIDefinesZeroReg ? AArch64::SUBSWrs : AArch64::SUBWrs;
+ case AArch64::SUBSWrx:
+ return AArch64::SUBWrx;
+ case AArch64::SUBSXrr:
+ return AArch64::SUBXrr;
+ case AArch64::SUBSXri:
+ return MIDefinesZeroReg ? AArch64::SUBSXri : AArch64::SUBXri;
+ case AArch64::SUBSXrs:
+ return MIDefinesZeroReg ? AArch64::SUBSXrs : AArch64::SUBXrs;
+ case AArch64::SUBSXrx:
+ return AArch64::SUBXrx;
+ }
}
+/// True when condition code could be modified on the instruction
+/// trace starting at from and ending at to.
+static bool modifiesConditionCode(MachineInstr *From, MachineInstr *To,
+ const bool CheckOnlyCCWrites,
+ const TargetRegisterInfo *TRI) {
+ // We iterate backward starting \p To until we hit \p From
+ MachineBasicBlock::iterator I = To, E = From, B = To->getParent()->begin();
+
+ // Early exit if To is at the beginning of the BB.
+ if (I == B)
+ return true;
+
+ // Check whether the definition of SrcReg is in the same basic block as
+ // Compare. If not, assume the condition code gets modified on some path.
+ if (To->getParent() != From->getParent())
+ return true;
+
+ // Check that NZCV isn't set on the trace.
+ for (--I; I != E; --I) {
+ const MachineInstr &Instr = *I;
+
+ if (Instr.modifiesRegister(AArch64::NZCV, TRI) ||
+ (!CheckOnlyCCWrites && Instr.readsRegister(AArch64::NZCV, TRI)))
+ // This instruction modifies or uses NZCV after the one we want to
+ // change.
+ return true;
+ if (I == B)
+ // We currently don't allow the instruction trace to cross basic
+ // block boundaries
+ return true;
+ }
+ return false;
+}
/// optimizeCompareInstr - Convert the instruction supplying the argument to the
/// comparison into one that sets the zero bit in the flags register.
bool AArch64InstrInfo::optimizeCompareInstr(
// Replace SUBSWrr with SUBWrr if NZCV is not used.
int Cmp_NZCV = CmpInstr->findRegisterDefOperandIdx(AArch64::NZCV, true);
if (Cmp_NZCV != -1) {
+ if (CmpInstr->definesRegister(AArch64::WZR) ||
+ CmpInstr->definesRegister(AArch64::XZR)) {
+ CmpInstr->eraseFromParent();
+ return true;
+ }
unsigned Opc = CmpInstr->getOpcode();
unsigned NewOpc = convertFlagSettingOpcode(CmpInstr);
if (NewOpc == Opc)
if (!MI)
return false;
- // We iterate backward, starting from the instruction before CmpInstr and
- // stop when reaching the definition of the source register or done with the
- // basic block, to check whether NZCV is used or modified in between.
- MachineBasicBlock::iterator I = CmpInstr, E = MI,
- B = CmpInstr->getParent()->begin();
-
- // Early exit if CmpInstr is at the beginning of the BB.
- if (I == B)
- return false;
-
- // Check whether the definition of SrcReg is in the same basic block as
- // Compare. If not, we can't optimize away the Compare.
- if (MI->getParent() != CmpInstr->getParent())
- return false;
-
- // Check that NZCV isn't set between the comparison instruction and the one we
- // want to change.
+ bool CheckOnlyCCWrites = false;
const TargetRegisterInfo *TRI = &getRegisterInfo();
- for (--I; I != E; --I) {
- const MachineInstr &Instr = *I;
-
- if (Instr.modifiesRegister(AArch64::NZCV, TRI) ||
- Instr.readsRegister(AArch64::NZCV, TRI))
- // This instruction modifies or uses NZCV after the one we want to
- // change. We can't do this transformation.
- return false;
- if (I == B)
- // The 'and' is below the comparison instruction.
- return false;
- }
+ if (modifiesConditionCode(MI, CmpInstr, CheckOnlyCCWrites, TRI))
+ return false;
unsigned NewOpc = MI->getOpcode();
switch (MI->getOpcode()) {
}
}
-MachineInstr *AArch64InstrInfo::emitFrameIndexDebugValue(MachineFunction &MF,
- int FrameIx,
- uint64_t Offset,
- const MDNode *MDPtr,
- DebugLoc DL) const {
+MachineInstr *AArch64InstrInfo::emitFrameIndexDebugValue(
+ MachineFunction &MF, int FrameIx, uint64_t Offset, const MDNode *Var,
+ const MDNode *Expr, DebugLoc DL) const {
MachineInstrBuilder MIB = BuildMI(MF, DL, get(AArch64::DBG_VALUE))
.addFrameIndex(FrameIx)
.addImm(0)
.addImm(Offset)
- .addMetadata(MDPtr);
+ .addMetadata(Var)
+ .addMetadata(Expr);
return &*MIB;
}
RC = &AArch64::GPR32RegClass;
} else {
OrrOpc = AArch64::ORRXri;
- OrrRC = &AArch64::GPR64RegClass;
+ OrrRC = &AArch64::GPR64spRegClass;
BitSize = 64;
ZeroReg = AArch64::XZR;
Opc = AArch64::MADDXrrr;
return;
}
+
+/// \brief Replace csincr-branch sequence by simple conditional branch
+///
+/// Examples:
+/// 1.
+/// csinc w9, wzr, wzr, <condition code>
+/// tbnz w9, #0, 0x44
+/// to
+/// b.<inverted condition code>
+///
+/// 2.
+/// csinc w9, wzr, wzr, <condition code>
+/// tbz w9, #0, 0x44
+/// to
+/// b.<condition code>
+///
+/// \param MI Conditional Branch
+/// \return True when the simple conditional branch is generated
+///
+bool AArch64InstrInfo::optimizeCondBranch(MachineInstr *MI) const {
+ bool IsNegativeBranch = false;
+ bool IsTestAndBranch = false;
+ unsigned TargetBBInMI = 0;
+ switch (MI->getOpcode()) {
+ default:
+ llvm_unreachable("Unknown branch instruction?");
+ case AArch64::Bcc:
+ return false;
+ case AArch64::CBZW:
+ case AArch64::CBZX:
+ TargetBBInMI = 1;
+ break;
+ case AArch64::CBNZW:
+ case AArch64::CBNZX:
+ TargetBBInMI = 1;
+ IsNegativeBranch = true;
+ break;
+ case AArch64::TBZW:
+ case AArch64::TBZX:
+ TargetBBInMI = 2;
+ IsTestAndBranch = true;
+ break;
+ case AArch64::TBNZW:
+ case AArch64::TBNZX:
+ TargetBBInMI = 2;
+ IsNegativeBranch = true;
+ IsTestAndBranch = true;
+ break;
+ }
+ // So we increment a zero register and test for bits other
+ // than bit 0? Conservatively bail out in case the verifier
+ // missed this case.
+ if (IsTestAndBranch && MI->getOperand(1).getImm())
+ return false;
+
+ // Find Definition.
+ assert(MI->getParent() && "Incomplete machine instruciton\n");
+ MachineBasicBlock *MBB = MI->getParent();
+ MachineFunction *MF = MBB->getParent();
+ MachineRegisterInfo *MRI = &MF->getRegInfo();
+ unsigned VReg = MI->getOperand(0).getReg();
+ if (!TargetRegisterInfo::isVirtualRegister(VReg))
+ return false;
+
+ MachineInstr *DefMI = MRI->getVRegDef(VReg);
+
+ // Look for CSINC
+ if (!(DefMI->getOpcode() == AArch64::CSINCWr &&
+ DefMI->getOperand(1).getReg() == AArch64::WZR &&
+ DefMI->getOperand(2).getReg() == AArch64::WZR) &&
+ !(DefMI->getOpcode() == AArch64::CSINCXr &&
+ DefMI->getOperand(1).getReg() == AArch64::XZR &&
+ DefMI->getOperand(2).getReg() == AArch64::XZR))
+ return false;
+
+ if (DefMI->findRegisterDefOperandIdx(AArch64::NZCV, true) != -1)
+ return false;
+
+ AArch64CC::CondCode CC =
+ (AArch64CC::CondCode)DefMI->getOperand(3).getImm();
+ bool CheckOnlyCCWrites = true;
+ // Convert only when the condition code is not modified between
+ // the CSINC and the branch. The CC may be used by other
+ // instructions in between.
+ if (modifiesConditionCode(DefMI, MI, CheckOnlyCCWrites, &getRegisterInfo()))
+ return false;
+ MachineBasicBlock &RefToMBB = *MBB;
+ MachineBasicBlock *TBB = MI->getOperand(TargetBBInMI).getMBB();
+ DebugLoc DL = MI->getDebugLoc();
+ if (IsNegativeBranch)
+ CC = AArch64CC::getInvertedCondCode(CC);
+ BuildMI(RefToMBB, MI, DL, get(AArch64::Bcc)).addImm(CC).addMBB(TBB);
+ MI->eraseFromParent();
+ return true;
+}
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