Add support for encoding immediates in icmp and fcmp. Hopefully, this will
remove a fair number of unnecessary materialized constants.
rdar://10412592
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144163 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 3c6d1e8..23629e7 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -1206,16 +1206,42 @@
if (isFloat && !Subtarget->hasVFP2())
return false;
+ // Check to see if the 2nd operand is a constant that we can encode directly
+ // in the compare.
+ uint64_t Imm;
+ int EncodedImm = 0;
+ bool EncodeImm = false;
+ bool isNegativeImm = false;
+ if (const ConstantInt *ConstInt = dyn_cast<ConstantInt>(Src2Value)) {
+ if (SrcVT == MVT::i32 || SrcVT == MVT::i16 || SrcVT == MVT::i8 ||
+ SrcVT == MVT::i1) {
+ const APInt &CIVal = ConstInt->getValue();
+
+ isNegativeImm = CIVal.isNegative();
+ Imm = (isNegativeImm) ? (-CIVal).getZExtValue() : CIVal.getZExtValue();
+ EncodedImm = (int)Imm;
+ EncodeImm = isThumb2 ? (ARM_AM::getT2SOImmVal(EncodedImm) != -1) :
+ (ARM_AM::getSOImmVal(EncodedImm) != -1);
+ }
+ } else if (const ConstantFP *ConstFP = dyn_cast<ConstantFP>(Src2Value)) {
+ if (SrcVT == MVT::f32 || SrcVT == MVT::f64)
+ if (ConstFP->isZero() && !ConstFP->isNegative())
+ EncodeImm = true;
+ }
+
unsigned CmpOpc;
+ bool isICmp = true;
bool needsExt = false;
switch (SrcVT.getSimpleVT().SimpleTy) {
default: return false;
// TODO: Verify compares.
case MVT::f32:
- CmpOpc = ARM::VCMPES;
+ isICmp = false;
+ CmpOpc = EncodeImm ? ARM::VCMPEZS : ARM::VCMPES;
break;
case MVT::f64:
- CmpOpc = ARM::VCMPED;
+ isICmp = false;
+ CmpOpc = EncodeImm ? ARM::VCMPEZD : ARM::VCMPED;
break;
case MVT::i1:
case MVT::i8:
@@ -1223,30 +1249,56 @@
needsExt = true;
// Intentional fall-through.
case MVT::i32:
- CmpOpc = isThumb2 ? ARM::t2CMPrr : ARM::CMPrr;
+ if (isThumb2) {
+ if (!EncodeImm)
+ CmpOpc = ARM::t2CMPrr;
+ else
+ CmpOpc = isNegativeImm ? ARM::t2CMNzri : ARM::t2CMPri;
+ } else {
+ if (!EncodeImm)
+ CmpOpc = ARM::CMPrr;
+ else
+ CmpOpc = isNegativeImm ? ARM::CMNzri : ARM::CMPri;
+ }
break;
}
unsigned SrcReg1 = getRegForValue(Src1Value);
if (SrcReg1 == 0) return false;
- unsigned SrcReg2 = getRegForValue(Src2Value);
- if (SrcReg2 == 0) return false;
+ unsigned SrcReg2;
+ if (!EncodeImm) {
+ SrcReg2 = getRegForValue(Src2Value);
+ if (SrcReg2 == 0) return false;
+ }
// We have i1, i8, or i16, we need to either zero extend or sign extend.
if (needsExt) {
unsigned ResultReg;
- EVT DestVT = MVT::i32;
- ResultReg = ARMEmitIntExt(SrcVT, SrcReg1, DestVT, isZExt);
+ ResultReg = ARMEmitIntExt(SrcVT, SrcReg1, MVT::i32, isZExt);
if (ResultReg == 0) return false;
SrcReg1 = ResultReg;
- ResultReg = ARMEmitIntExt(SrcVT, SrcReg2, DestVT, isZExt);
- if (ResultReg == 0) return false;
- SrcReg2 = ResultReg;
+ if (!EncodeImm) {
+ ResultReg = ARMEmitIntExt(SrcVT, SrcReg2, MVT::i32, isZExt);
+ if (ResultReg == 0) return false;
+ SrcReg2 = ResultReg;
+ }
}
- AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(CmpOpc))
- .addReg(SrcReg1).addReg(SrcReg2));
+ if (!EncodeImm) {
+ AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
+ TII.get(CmpOpc))
+ .addReg(SrcReg1).addReg(SrcReg2));
+ } else {
+ MachineInstrBuilder MIB;
+ MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(CmpOpc))
+ .addReg(SrcReg1);
+
+ // Only add immediate for icmp as the immediate for fcmp is an implicit 0.0.
+ if (isICmp)
+ MIB.addImm(EncodedImm);
+ AddOptionalDefs(MIB);
+ }
// For floating point we need to move the result to a comparison register
// that we can then use for branches.