[SelectionDAG] In InstrEmitter, handle EXTRACT_SUBREG of a physical register.
Summary:
Without this change, the getVR() call would hit an assert since it was
being passed a physical register.
Update the AArch64/ldst-opt.ll test with a case that triggers this
behavior by adding a run with strict-align, which causes an unaligned
STR XZR instruction to be split into byte stores, creating an
EXTRACT_SUBREG of XZR that triggers the original problem.
Reviewers: bogner, qcolombet, MatzeB, atrick
Subscribers: aemerson, mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D29495
llvm-svn: 294129
diff --git a/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index 3b91e58..4a9042c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -502,8 +502,17 @@
const TargetRegisterClass *TRC =
TLI->getRegClassFor(Node->getSimpleValueType(0));
- unsigned VReg = getVR(Node->getOperand(0), VRBaseMap);
- MachineInstr *DefMI = MRI->getVRegDef(VReg);
+ unsigned Reg;
+ MachineInstr *DefMI;
+ RegisterSDNode *R = dyn_cast<RegisterSDNode>(Node->getOperand(0));
+ if (R && TargetRegisterInfo::isPhysicalRegister(R->getReg())) {
+ Reg = R->getReg();
+ DefMI = nullptr;
+ } else {
+ Reg = getVR(Node->getOperand(0), VRBaseMap);
+ DefMI = MRI->getVRegDef(Reg);
+ }
+
unsigned SrcReg, DstReg, DefSubIdx;
if (DefMI &&
TII->isCoalescableExtInstr(*DefMI, SrcReg, DstReg, DefSubIdx) &&
@@ -519,20 +528,26 @@
TII->get(TargetOpcode::COPY), VRBase).addReg(SrcReg);
MRI->clearKillFlags(SrcReg);
} else {
- // VReg may not support a SubIdx sub-register, and we may need to
+ // Reg may not support a SubIdx sub-register, and we may need to
// constrain its register class or issue a COPY to a compatible register
// class.
- VReg = ConstrainForSubReg(VReg, SubIdx,
- Node->getOperand(0).getSimpleValueType(),
- Node->getDebugLoc());
+ if (TargetRegisterInfo::isVirtualRegister(Reg))
+ Reg = ConstrainForSubReg(Reg, SubIdx,
+ Node->getOperand(0).getSimpleValueType(),
+ Node->getDebugLoc());
// Create the destreg if it is missing.
if (VRBase == 0)
VRBase = MRI->createVirtualRegister(TRC);
// Create the extract_subreg machine instruction.
- BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
- TII->get(TargetOpcode::COPY), VRBase).addReg(VReg, 0, SubIdx);
+ MachineInstrBuilder CopyMI =
+ BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
+ TII->get(TargetOpcode::COPY), VRBase);
+ if (TargetRegisterInfo::isVirtualRegister(Reg))
+ CopyMI.addReg(Reg, 0, SubIdx);
+ else
+ CopyMI.addReg(TRI->getSubReg(Reg, SubIdx));
}
} else if (Opc == TargetOpcode::INSERT_SUBREG ||
Opc == TargetOpcode::SUBREG_TO_REG) {