Implement Thumb2 ldr.
After much back and forth, I decided to deviate from ARM design and split LDR into 4 instructions (r + imm12, r + imm8, r + r << imm12, constantpool). The advantage of this is 1) it follows the latest ARM technical manual, and 2) makes it easier to reduce the width of the instruction later. The down side is this creates more inconsistency between the two sub-targets. We should split ARM LDR instruction in a similar fashion later. I've added a README entry for this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74420 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 200371b..7035064 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -64,6 +64,8 @@
SDNode *Select(SDValue Op);
virtual void InstructionSelect();
+ bool SelectShifterOperandReg(SDValue Op, SDValue N, SDValue &A,
+ SDValue &B, SDValue &C);
bool SelectAddrMode2(SDValue Op, SDValue N, SDValue &Base,
SDValue &Offset, SDValue &Opc);
bool SelectAddrMode2Offset(SDValue Op, SDValue N,
@@ -92,10 +94,15 @@
bool SelectThumbAddrModeSP(SDValue Op, SDValue N, SDValue &Base,
SDValue &OffImm);
- bool SelectShifterOperandReg(SDValue Op, SDValue N, SDValue &A,
- SDValue &B, SDValue &C);
bool SelectT2ShifterOperandReg(SDValue Op, SDValue N,
SDValue &BaseReg, SDValue &Opc);
+ bool SelectT2AddrModeImm12(SDValue Op, SDValue N, SDValue &Base,
+ SDValue &OffImm);
+ bool SelectT2AddrModeImm8(SDValue Op, SDValue N, SDValue &Base,
+ SDValue &OffImm);
+ bool SelectT2AddrModeSoReg(SDValue Op, SDValue N, SDValue &Base,
+ SDValue &OffReg, SDValue &ShImm);
+
// Include the pieces autogenerated from the target description.
#include "ARMGenDAGISel.inc"
@@ -116,6 +123,30 @@
CurDAG->RemoveDeadNodes();
}
+bool ARMDAGToDAGISel::SelectShifterOperandReg(SDValue Op,
+ 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;
+ 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);
+ return true;
+}
+
bool ARMDAGToDAGISel::SelectAddrMode2(SDValue Op, SDValue N,
SDValue &Base, SDValue &Offset,
SDValue &Opc) {
@@ -519,30 +550,6 @@
return false;
}
-bool ARMDAGToDAGISel::SelectShifterOperandReg(SDValue Op,
- 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;
- 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);
- return true;
-}
-
bool ARMDAGToDAGISel::SelectT2ShifterOperandReg(SDValue Op, SDValue N,
SDValue &BaseReg,
SDValue &Opc) {
@@ -563,6 +570,106 @@
return false;
}
+bool ARMDAGToDAGISel::SelectT2AddrModeImm12(SDValue Op, SDValue N,
+ SDValue &Base, SDValue &OffImm) {
+ // Match simple R + imm12 operands.
+ if (N.getOpcode() != ISD::ADD)
+ return false;
+
+ if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
+ int RHSC = (int)RHS->getZExtValue();
+ if (RHSC >= 0 && RHSC < 0x1000) { // 12 bits.
+ Base = N.getOperand(0);
+ OffImm = CurDAG->getTargetConstant(RHSC, MVT::i32);
+ return true;
+ }
+ }
+
+ return false;
+}
+
+bool ARMDAGToDAGISel::SelectT2AddrModeImm8(SDValue Op, SDValue N,
+ SDValue &Base, SDValue &OffImm) {
+ if (N.getOpcode() == ISD::ADD) {
+ if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
+ int RHSC = (int)RHS->getZExtValue();
+ if (RHSC < 0 && RHSC > -0x100) { // 8 bits.
+ Base = N.getOperand(0);
+ OffImm = CurDAG->getTargetConstant(RHSC, MVT::i32);
+ return true;
+ }
+ }
+ } else if (N.getOpcode() == ISD::SUB) {
+ if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
+ int RHSC = (int)RHS->getZExtValue();
+ if (RHSC >= 0 && RHSC < 0x100) { // 8 bits.
+ Base = N.getOperand(0);
+ OffImm = CurDAG->getTargetConstant(-RHSC, MVT::i32);
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+
+bool ARMDAGToDAGISel::SelectT2AddrModeSoReg(SDValue Op, SDValue N,
+ SDValue &Base,
+ SDValue &OffReg, SDValue &ShImm) {
+ // Base only.
+ if (N.getOpcode() != ISD::ADD && N.getOpcode() != ISD::SUB) {
+ Base = N;
+ if (N.getOpcode() == ISD::FrameIndex) {
+ int FI = cast<FrameIndexSDNode>(N)->getIndex();
+ Base = CurDAG->getTargetFrameIndex(FI, TLI.getPointerTy());
+ } else if (N.getOpcode() == ARMISD::Wrapper) {
+ Base = N.getOperand(0);
+ if (Base.getOpcode() == ISD::TargetConstantPool)
+ return false; // We want to select t2LDRpci instead.
+ }
+ OffReg = CurDAG->getRegister(0, MVT::i32);
+ ShImm = CurDAG->getTargetConstant(0, MVT::i32);
+ return true;
+ }
+
+ // Look for (R + R) or (R + (R << [1,2,3])).
+ unsigned ShAmt = 0;
+ Base = N.getOperand(0);
+ OffReg = N.getOperand(1);
+
+ // Swap if it is ((R << c) + R).
+ ARM_AM::ShiftOpc ShOpcVal = ARM_AM::getShiftOpcForNode(OffReg);
+ if (ShOpcVal != ARM_AM::lsl) {
+ ShOpcVal = ARM_AM::getShiftOpcForNode(Base);
+ if (ShOpcVal == ARM_AM::lsl)
+ std::swap(Base, OffReg);
+ }
+
+ if (ShOpcVal == ARM_AM::lsl) {
+ // Check to see if the RHS of the shift is a constant, if not, we can't fold
+ // it.
+ if (ConstantSDNode *Sh = dyn_cast<ConstantSDNode>(OffReg.getOperand(1))) {
+ ShAmt = Sh->getZExtValue();
+ if (ShAmt >= 4) {
+ ShAmt = 0;
+ ShOpcVal = ARM_AM::no_shift;
+ } else
+ OffReg = OffReg.getOperand(0);
+ } else {
+ ShOpcVal = ARM_AM::no_shift;
+ }
+ } else if (SelectT2AddrModeImm12(Op, N, Base, ShImm) ||
+ SelectT2AddrModeImm8 (Op, N, Base, ShImm))
+ // Don't match if it's possible to match to one of the r +/- imm cases.
+ return false;
+
+ ShImm = CurDAG->getTargetConstant(ShAmt, MVT::i32);
+
+ return true;
+}
+
+//===--------------------------------------------------------------------===//
+
/// getAL - Returns a ARMCC::AL immediate node.
static inline SDValue getAL(SelectionDAG *CurDAG) {
return CurDAG->getTargetConstant((uint64_t)ARMCC::AL, MVT::i32);