Implement code to convert SetCC into straight line code where appropriate. Add necessary instructions for this transformation to the .td file.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15952 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPC32ISelSimple.cpp b/lib/Target/PowerPC/PPC32ISelSimple.cpp
index e5f5728..a49f253 100644
--- a/lib/Target/PowerPC/PPC32ISelSimple.cpp
+++ b/lib/Target/PowerPC/PPC32ISelSimple.cpp
@@ -33,6 +33,7 @@
namespace {
Statistic<> GEPFolds("ppc-codegen", "Number of GEPs folded");
+ Statistic<> NumSetCC("ppc-codegen", "Number of SetCC straight-lined");
/// TypeClass - Used by the PowerPC backend to group LLVM types by their basic
/// PPC Representation.
@@ -280,6 +281,10 @@
abort();
}
+ unsigned ExtendOrClear(MachineBasicBlock *MBB,
+ MachineBasicBlock::iterator IP,
+ unsigned Reg, const Type *CompTy);
+
/// promote32 - Make a value 32-bits wide, and put it somewhere.
///
void promote32(unsigned targetReg, const ValueRecord &VR);
@@ -959,6 +964,33 @@
BuildMI(*MBB, IP, PPC::FCMPU, 2, PPC::CR0).addReg(LHS).addReg(RHS);
}
+unsigned ISel::ExtendOrClear(MachineBasicBlock *MBB,
+ MachineBasicBlock::iterator IP,
+ unsigned Reg, const Type *CompTy) {
+ unsigned Class = getClassB(CompTy);
+
+ // Before we do a comparison or SetCC, we have to make sure that we truncate
+ // the source registers appropriately.
+ if (Class == cByte) {
+ unsigned TmpReg = makeAnotherReg(CompTy);
+ if (CompTy->isSigned())
+ BuildMI(*MBB, IP, PPC::EXTSB, 1, TmpReg).addReg(Reg);
+ else
+ BuildMI(*MBB, IP, PPC::RLWINM, 4, TmpReg).addReg(Reg).addImm(0)
+ .addImm(24).addImm(31);
+ Reg = TmpReg;
+ } else if (Class == cShort) {
+ unsigned TmpReg = makeAnotherReg(CompTy);
+ if (CompTy->isSigned())
+ BuildMI(*MBB, IP, PPC::EXTSH, 1, TmpReg).addReg(Reg);
+ else
+ BuildMI(*MBB, IP, PPC::RLWINM, 4, TmpReg).addReg(Reg).addImm(0)
+ .addImm(16).addImm(31);
+ Reg = TmpReg;
+ }
+ return Reg;
+}
+
/// EmitComparison - emits a comparison of the two operands, returning the
/// extended setcc code to use. The result is in CR0.
///
@@ -968,27 +1000,7 @@
// The arguments are already supposed to be of the same type.
const Type *CompTy = Op0->getType();
unsigned Class = getClassB(CompTy);
- unsigned Op0r = getReg(Op0, MBB, IP);
-
- // Before we do a comparison, we have to make sure that we're truncating our
- // registers appropriately.
- if (Class == cByte) {
- unsigned TmpReg = makeAnotherReg(CompTy);
- if (CompTy->isSigned())
- BuildMI(*MBB, IP, PPC::EXTSB, 1, TmpReg).addReg(Op0r);
- else
- BuildMI(*MBB, IP, PPC::RLWINM, 4, TmpReg).addReg(Op0r).addImm(0)
- .addImm(24).addImm(31);
- Op0r = TmpReg;
- } else if (Class == cShort) {
- unsigned TmpReg = makeAnotherReg(CompTy);
- if (CompTy->isSigned())
- BuildMI(*MBB, IP, PPC::EXTSH, 1, TmpReg).addReg(Op0r);
- else
- BuildMI(*MBB, IP, PPC::RLWINM, 4, TmpReg).addReg(Op0r).addImm(0)
- .addImm(16).addImm(31);
- Op0r = TmpReg;
- }
+ unsigned Op0r = ExtendOrClear(MBB, IP, getReg(Op0, MBB, IP), CompTy);
// Use crand for lt, gt and crandc for le, ge
unsigned CROpcode = (OpNum == 2 || OpNum == 4) ? PPC::CRAND : PPC::CRANDC;
@@ -1098,13 +1110,148 @@
if (canFoldSetCCIntoBranchOrSelect(&I))
return;
+ Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ const Type *Ty = Op0->getType();
+ unsigned Class = getClassB(Ty);
+ unsigned Opcode = I.getOpcode();
unsigned DestReg = getReg(I);
- unsigned OpNum = I.getOpcode();
- const Type *Ty = I.getOperand (0)->getType();
- EmitComparison(OpNum, I.getOperand(0), I.getOperand(1), BB, BB->end());
+ // If the comparison type is byte, short, or int, then we can emit a
+ // branchless version of the SetCC that puts 0 (false) or 1 (true) in the
+ // destination register.
+ if (Class <= cInt) {
+ ++NumSetCC;
+ MachineBasicBlock::iterator MI = BB->end();
+ unsigned OpNum = getSetCCNumber(Opcode);
+ unsigned Op0Reg = getReg(Op0, BB, MI);
+ Op0Reg = ExtendOrClear(BB, MI, Op0Reg, Ty);
+
+ // comparisons against constant zero often have shorter sequences than the
+ // general case, handled below.
+ ConstantInt *CI = dyn_cast<ConstantInt>(Op1);
+ if (CI && CI->getRawValue() == 0) {
+ switch(OpNum) {
+ case 0: { // eq0
+ unsigned TempReg = makeAnotherReg(Type::IntTy);
+ BuildMI(*BB, MI, PPC::CNTLZW, 1, TempReg).addReg(Op0Reg);
+ BuildMI(*BB, MI, PPC::SRWI, 2, DestReg).addReg(TempReg).addImm(5);
+ break;
+ }
+ case 1: { // ne0
+ unsigned TempReg = makeAnotherReg(Type::IntTy);
+ BuildMI(*BB, MI, PPC::ADDIC, 2, TempReg).addReg(Op0Reg).addSImm(-1);
+ BuildMI(*BB, MI, PPC::SUBFE, 2, DestReg).addReg(TempReg).addReg(Op0Reg);
+ break;
+ }
+ case 2: { // lt0, always false if unsigned
+ if (Ty->isSigned())
+ BuildMI(*BB, MI, PPC::SRWI, 2, DestReg).addReg(Op0Reg).addImm(31);
+ else
+ BuildMI(*BB, MI, PPC::LI, 1, DestReg).addSImm(0);
+ break;
+ }
+ case 3: { // ge0, always true if unsigned
+ if (Ty->isSigned()) {
+ unsigned TempReg = makeAnotherReg(Type::IntTy);
+ BuildMI(*BB, MI, PPC::SRWI, 2, TempReg).addReg(Op0Reg).addImm(31);
+ BuildMI(*BB, MI, PPC::XORI, 2, DestReg).addReg(TempReg).addImm(1);
+ } else {
+ BuildMI(*BB, MI, PPC::LI, 1, DestReg).addSImm(1);
+ }
+ break;
+ }
+ case 4: { // gt0, equivalent to ne0 if unsigned
+ unsigned Temp1 = makeAnotherReg(Type::IntTy);
+ unsigned Temp2 = makeAnotherReg(Type::IntTy);
+ if (Ty->isSigned()) {
+ BuildMI(*BB, MI, PPC::NEG, 2, Temp1).addReg(Op0Reg);
+ BuildMI(*BB, MI, PPC::ANDC, 2, Temp2).addReg(Temp1).addReg(Op0Reg);
+ BuildMI(*BB, MI, PPC::SRWI, 2, DestReg).addReg(Temp2).addImm(31);
+ } else {
+ BuildMI(*BB, MI, PPC::ADDIC, 2, Temp1).addReg(Op0Reg).addSImm(-1);
+ BuildMI(*BB, MI, PPC::SUBFE, 2, DestReg).addReg(Temp1).addReg(Op0Reg);
+ }
+ break;
+ }
+ case 5: { // le0, equivalent to eq0 if unsigned
+ unsigned Temp1 = makeAnotherReg(Type::IntTy);
+ unsigned Temp2 = makeAnotherReg(Type::IntTy);
+ if (Ty->isSigned()) {
+ BuildMI(*BB, MI, PPC::NEG, 2, Temp1).addReg(Op0Reg);
+ BuildMI(*BB, MI, PPC::ORC, 2, Temp2).addReg(Op0Reg).addReg(Temp1);
+ BuildMI(*BB, MI, PPC::SRWI, 2, DestReg).addReg(Temp2).addImm(31);
+ } else {
+ BuildMI(*BB, MI, PPC::CNTLZW, 1, Temp1).addReg(Op0Reg);
+ BuildMI(*BB, MI, PPC::SRWI, 2, DestReg).addReg(Temp1).addImm(5);
+ }
+ break;
+ }
+ } // switch
+ return;
+ }
+ unsigned Op1Reg = getReg(Op1, BB, MI);
+ switch(OpNum) {
+ case 0: { // eq
+ unsigned Temp1 = makeAnotherReg(Type::IntTy);
+ unsigned Temp2 = makeAnotherReg(Type::IntTy);
+ BuildMI(*BB, MI, PPC::SUBF, 2, Temp1).addReg(Op0Reg).addReg(Op1Reg);
+ BuildMI(*BB, MI, PPC::CNTLZW, 1, Temp2).addReg(Temp1);
+ BuildMI(*BB, MI, PPC::SRWI, 2, DestReg).addReg(Temp2).addImm(5);
+ break;
+ }
+ case 1: { // ne
+ unsigned Temp1 = makeAnotherReg(Type::IntTy);
+ unsigned Temp2 = makeAnotherReg(Type::IntTy);
+ BuildMI(*BB, MI, PPC::SUBF, 2, Temp1).addReg(Op0Reg).addReg(Op1Reg);
+ BuildMI(*BB, MI, PPC::ADDIC, 2, Temp2).addReg(Temp1).addSImm(-1);
+ BuildMI(*BB, MI, PPC::SUBFE, 2, DestReg).addReg(Temp2).addReg(Temp1);
+ break;
+ }
+ case 2:
+ case 4: { // lt, gt
+ unsigned Temp1 = makeAnotherReg(Type::IntTy);
+ unsigned Temp2 = makeAnotherReg(Type::IntTy);
+ unsigned Temp3 = makeAnotherReg(Type::IntTy);
+ unsigned Temp4 = makeAnotherReg(Type::IntTy);
+ if (OpNum == 4) std::swap(Op0Reg, Op1Reg);
+ if (Ty->isSigned()) {
+ BuildMI(*BB, MI, PPC::SUBFC, 2, Temp1).addReg(Op1Reg).addReg(Op0Reg);
+ BuildMI(*BB, MI, PPC::EQV, 2, Temp2).addReg(Op1Reg).addReg(Op0Reg);
+ BuildMI(*BB, MI, PPC::SRWI, 2, Temp3).addReg(Temp2).addImm(31);
+ BuildMI(*BB, MI, PPC::ADDZE, 1, Temp4).addReg(Temp3);
+ BuildMI(*BB, MI, PPC::RLWINM, 4, DestReg).addReg(Temp4).addImm(0)
+ .addImm(31).addImm(31);
+ } else {
+ BuildMI(*BB, MI, PPC::SUBFC, 2, Temp1).addReg(Op1Reg).addReg(Op0Reg);
+ BuildMI(*BB, MI, PPC::SUBFE, 2, Temp2).addReg(Temp1).addReg(Temp1);
+ BuildMI(*BB, MI, PPC::NEG, 2, DestReg).addReg(Temp2);
+ }
+ break;
+ }
+ case 3:
+ case 5: { // le, ge
+ unsigned Temp1 = makeAnotherReg(Type::IntTy);
+ unsigned Temp2 = makeAnotherReg(Type::IntTy);
+ unsigned Temp3 = makeAnotherReg(Type::IntTy);
+ if (OpNum == 3) std::swap(Op0Reg, Op1Reg);
+ if (Ty->isSigned()) {
+ BuildMI(*BB, MI, PPC::SRWI, 2, Temp1).addReg(Op0Reg).addImm(31);
+ BuildMI(*BB, MI, PPC::SRAWI, 2, Temp2).addReg(Op1Reg).addImm(31);
+ BuildMI(*BB, MI, PPC::SUBFC, 2, Temp3).addReg(Op0Reg).addReg(Op1Reg);
+ BuildMI(*BB, MI, PPC::ADDE, 2, DestReg).addReg(Temp2).addReg(Temp1);
+ } else {
+ BuildMI(*BB, MI, PPC::LI, 1, Temp2).addSImm(-1);
+ BuildMI(*BB, MI, PPC::SUBFC, 2, Temp1).addReg(Op0Reg).addReg(Op1Reg);
+ BuildMI(*BB, MI, PPC::SUBFZE, 1, DestReg).addReg(Temp2);
+ }
+ break;
+ }
+ } // switch
+ return;
+ }
+ EmitComparison(Opcode, Op0, Op1, BB, BB->end());
- unsigned Opcode = getPPCOpcodeForSetCCNumber(OpNum);
+ unsigned PPCOpcode = getPPCOpcodeForSetCCNumber(Opcode);
MachineBasicBlock *thisMBB = BB;
const BasicBlock *LLVM_BB = BB->getBasicBlock();
ilist<MachineBasicBlock>::iterator It = BB;
@@ -1121,7 +1268,7 @@
// bCC. But MBB->getFirstTerminator() can't understand this.
MachineBasicBlock *copy1MBB = new MachineBasicBlock(LLVM_BB);
F->getBasicBlockList().insert(It, copy1MBB);
- BuildMI(BB, Opcode, 2).addReg(PPC::CR0).addMBB(copy1MBB);
+ BuildMI(BB, PPCOpcode, 2).addReg(PPC::CR0).addMBB(copy1MBB);
MachineBasicBlock *copy0MBB = new MachineBasicBlock(LLVM_BB);
F->getBasicBlockList().insert(It, copy0MBB);
BuildMI(BB, PPC::B, 1).addMBB(copy0MBB);