Shifter ops are not always free. Do not fold them (especially to form
complex load / store addressing mode) when they have higher cost and
when they have more than one use.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117509 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 5285a43..ec66cea 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -78,8 +78,12 @@
SDNode *Select(SDNode *N);
+ bool isShifterOpProfitable(const SDValue &Shift,
+ ARM_AM::ShiftOpc ShOpcVal, unsigned ShAmt);
bool SelectShifterOperandReg(SDValue N, SDValue &A,
SDValue &B, SDValue &C);
+ bool SelectShiftShifterOperandReg(SDValue N, SDValue &A,
+ SDValue &B, SDValue &C);
bool SelectAddrModeImm12(SDValue N, SDValue &Base, SDValue &OffImm);
bool SelectLdStSOReg(SDValue N, SDValue &Base, SDValue &Offset, SDValue &Opc);
@@ -246,6 +250,17 @@
}
+bool ARMDAGToDAGISel::isShifterOpProfitable(const SDValue &Shift,
+ ARM_AM::ShiftOpc ShOpcVal,
+ unsigned ShAmt) {
+ if (!Subtarget->isCortexA9())
+ return true;
+ if (Shift.hasOneUse())
+ return true;
+ // R << 2 is free.
+ return ShOpcVal == ARM_AM::lsl && ShAmt == 2;
+}
+
bool ARMDAGToDAGISel::SelectShifterOperandReg(SDValue N,
SDValue &BaseReg,
SDValue &ShReg,
@@ -266,6 +281,32 @@
ShImmVal = RHS->getZExtValue() & 31;
} else {
ShReg = N.getOperand(1);
+ if (!isShifterOpProfitable(N, ShOpcVal, ShImmVal))
+ return false;
+ }
+ Opc = CurDAG->getTargetConstant(ARM_AM::getSORegOpc(ShOpcVal, ShImmVal),
+ MVT::i32);
+ return true;
+}
+
+bool ARMDAGToDAGISel::SelectShiftShifterOperandReg(SDValue N,
+ SDValue &BaseReg,
+ SDValue &ShReg,
+ SDValue &Opc) {
+ ARM_AM::ShiftOpc ShOpcVal = ARM_AM::getShiftOpcForNode(N);
+
+ // Don't match base register only case. That is matched to a separate
+ // lower complexity pattern with explicit register operand.
+ if (ShOpcVal == ARM_AM::no_shift) return false;
+
+ BaseReg = N.getOperand(0);
+ unsigned ShImmVal = 0;
+ // Do not check isShifterOpProfitable. This must return true.
+ if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
+ ShReg = CurDAG->getRegister(0, MVT::i32);
+ ShImmVal = RHS->getZExtValue() & 31;
+ } else {
+ ShReg = N.getOperand(1);
}
Opc = CurDAG->getTargetConstant(ARM_AM::getSORegOpc(ShOpcVal, ShImmVal),
MVT::i32);
@@ -321,7 +362,8 @@
bool ARMDAGToDAGISel::SelectLdStSOReg(SDValue N, SDValue &Base, SDValue &Offset,
SDValue &Opc) {
- if (N.getOpcode() == ISD::MUL) {
+ if (N.getOpcode() == ISD::MUL &&
+ (!Subtarget->isCortexA9() || N.hasOneUse())) {
if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
// X * [3,5,9] -> X + X * [2,4,8] etc.
int RHSC = (int)RHS->getZExtValue();
@@ -357,6 +399,10 @@
}
}
+ if (Subtarget->isCortexA9() && !N.hasOneUse())
+ // Compute R +/- (R << N) and reuse it.
+ return false;
+
// Otherwise this is R +/- [possibly shifted] R.
ARM_AM::AddrOpc AddSub = N.getOpcode() == ISD::ADD ? ARM_AM::add:ARM_AM::sub;
ARM_AM::ShiftOpc ShOpcVal = ARM_AM::getShiftOpcForNode(N.getOperand(1));
@@ -371,14 +417,20 @@
if (ConstantSDNode *Sh =
dyn_cast<ConstantSDNode>(N.getOperand(1).getOperand(1))) {
ShAmt = Sh->getZExtValue();
- Offset = N.getOperand(1).getOperand(0);
+ if (isShifterOpProfitable(Offset, ShOpcVal, ShAmt))
+ Offset = N.getOperand(1).getOperand(0);
+ else {
+ ShAmt = 0;
+ ShOpcVal = ARM_AM::no_shift;
+ }
} else {
ShOpcVal = ARM_AM::no_shift;
}
}
// Try matching (R shl C) + (R).
- if (N.getOpcode() == ISD::ADD && ShOpcVal == ARM_AM::no_shift) {
+ if (N.getOpcode() == ISD::ADD && ShOpcVal == ARM_AM::no_shift &&
+ !(Subtarget->isCortexA9() || N.getOperand(0).hasOneUse())) {
ShOpcVal = ARM_AM::getShiftOpcForNode(N.getOperand(0));
if (ShOpcVal != ARM_AM::no_shift) {
// Check to see if the RHS of the shift is a constant, if not, we can't
@@ -386,8 +438,15 @@
if (ConstantSDNode *Sh =
dyn_cast<ConstantSDNode>(N.getOperand(0).getOperand(1))) {
ShAmt = Sh->getZExtValue();
- Offset = N.getOperand(0).getOperand(0);
- Base = N.getOperand(1);
+ if (!Subtarget->isCortexA9() ||
+ (N.hasOneUse() &&
+ isShifterOpProfitable(N.getOperand(0), ShOpcVal, ShAmt))) {
+ Offset = N.getOperand(0).getOperand(0);
+ Base = N.getOperand(1);
+ } else {
+ ShAmt = 0;
+ ShOpcVal = ARM_AM::no_shift;
+ }
} else {
ShOpcVal = ARM_AM::no_shift;
}
@@ -408,7 +467,8 @@
SDValue &Base,
SDValue &Offset,
SDValue &Opc) {
- if (N.getOpcode() == ISD::MUL) {
+ if (N.getOpcode() == ISD::MUL &&
+ (!Subtarget->isCortexA9() || N.hasOneUse())) {
if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
// X * [3,5,9] -> X + X * [2,4,8] etc.
int RHSC = (int)RHS->getZExtValue();
@@ -474,6 +534,16 @@
}
}
+ if (Subtarget->isCortexA9() && !N.hasOneUse()) {
+ // Compute R +/- (R << N) and reuse it.
+ Base = N;
+ Offset = CurDAG->getRegister(0, MVT::i32);
+ Opc = CurDAG->getTargetConstant(ARM_AM::getAM2Opc(ARM_AM::add, 0,
+ ARM_AM::no_shift),
+ MVT::i32);
+ return AM2_BASE;
+ }
+
// Otherwise this is R +/- [possibly shifted] R.
ARM_AM::AddrOpc AddSub = N.getOpcode() == ISD::ADD ? ARM_AM::add:ARM_AM::sub;
ARM_AM::ShiftOpc ShOpcVal = ARM_AM::getShiftOpcForNode(N.getOperand(1));
@@ -488,14 +558,20 @@
if (ConstantSDNode *Sh =
dyn_cast<ConstantSDNode>(N.getOperand(1).getOperand(1))) {
ShAmt = Sh->getZExtValue();
- Offset = N.getOperand(1).getOperand(0);
+ if (isShifterOpProfitable(Offset, ShOpcVal, ShAmt))
+ Offset = N.getOperand(1).getOperand(0);
+ else {
+ ShAmt = 0;
+ ShOpcVal = ARM_AM::no_shift;
+ }
} else {
ShOpcVal = ARM_AM::no_shift;
}
}
// Try matching (R shl C) + (R).
- if (N.getOpcode() == ISD::ADD && ShOpcVal == ARM_AM::no_shift) {
+ if (N.getOpcode() == ISD::ADD && ShOpcVal == ARM_AM::no_shift &&
+ !(Subtarget->isCortexA9() || N.getOperand(0).hasOneUse())) {
ShOpcVal = ARM_AM::getShiftOpcForNode(N.getOperand(0));
if (ShOpcVal != ARM_AM::no_shift) {
// Check to see if the RHS of the shift is a constant, if not, we can't
@@ -503,8 +579,15 @@
if (ConstantSDNode *Sh =
dyn_cast<ConstantSDNode>(N.getOperand(0).getOperand(1))) {
ShAmt = Sh->getZExtValue();
- Offset = N.getOperand(0).getOperand(0);
- Base = N.getOperand(1);
+ if (!Subtarget->isCortexA9() ||
+ (N.hasOneUse() &&
+ isShifterOpProfitable(N.getOperand(0), ShOpcVal, ShAmt))) {
+ Offset = N.getOperand(0).getOperand(0);
+ Base = N.getOperand(1);
+ } else {
+ ShAmt = 0;
+ ShOpcVal = ARM_AM::no_shift;
+ }
} else {
ShOpcVal = ARM_AM::no_shift;
}
@@ -543,7 +626,12 @@
// it.
if (ConstantSDNode *Sh = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
ShAmt = Sh->getZExtValue();
- Offset = N.getOperand(0);
+ if (isShifterOpProfitable(N, ShOpcVal, ShAmt))
+ Offset = N.getOperand(0);
+ else {
+ ShAmt = 0;
+ ShOpcVal = ARM_AM::no_shift;
+ }
} else {
ShOpcVal = ARM_AM::no_shift;
}
@@ -959,6 +1047,12 @@
return false;
}
+ if (Subtarget->isCortexA9() && !N.hasOneUse()) {
+ // Compute R + (R << [1,2,3]) and reuse it.
+ Base = N;
+ return false;
+ }
+
// Look for (R + R) or (R + (R << [1,2,3])).
unsigned ShAmt = 0;
Base = N.getOperand(0);
@@ -977,11 +1071,12 @@
// it.
if (ConstantSDNode *Sh = dyn_cast<ConstantSDNode>(OffReg.getOperand(1))) {
ShAmt = Sh->getZExtValue();
- if (ShAmt >= 4) {
+ if (ShAmt < 4 && isShifterOpProfitable(OffReg, ShOpcVal, ShAmt))
+ OffReg = OffReg.getOperand(0);
+ else {
ShAmt = 0;
ShOpcVal = ARM_AM::no_shift;
- } else
- OffReg = OffReg.getOperand(0);
+ }
} else {
ShOpcVal = ARM_AM::no_shift;
}