AMDGPU/GlobalISel: Implement select() for G_IMPLICIT_DEF

Reviewers: arsenm, nhaehnle

Subscribers: kzhuravl, wdng, yaxunl, rovka, kristof.beyls, dstuttard, tpr, t-tye, llvm-commits

Differential Revision: https://reviews.llvm.org/D46150

llvm-svn: 335307

1 files changed, 15 insertions, 0 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp b/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
index 0b605fd92a7..27bd191b93e 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
@@ -159,6 +159,19 @@ bool AMDGPUInstructionSelector::selectG_GEP(MachineInstr &I) const {
   return selectG_ADD(I);
 }
 
+bool AMDGPUInstructionSelector::selectG_IMPLICIT_DEF(MachineInstr &I) const {
+  MachineBasicBlock *BB = I.getParent();
+  MachineFunction *MF = BB->getParent();
+  MachineRegisterInfo &MRI = MF->getRegInfo();
+  const MachineOperand &MO = I.getOperand(0);
+  const TargetRegisterClass *RC =
+      TRI.getConstrainedRegClassForOperand(MO, MRI);
+  if (RC)
+    RBI.constrainGenericRegister(MO.getReg(), *RC, MRI);
+  I.setDesc(TII.get(TargetOpcode::IMPLICIT_DEF));
+  return true;
+}
+
 bool AMDGPUInstructionSelector::selectG_INTRINSIC(MachineInstr &I,
                                           CodeGenCoverage &CoverageInfo) const {
   unsigned IntrinsicID =  I.getOperand(1).getIntrinsicID();
@@ -535,6 +548,8 @@ bool AMDGPUInstructionSelector::select(MachineInstr &I,
     return selectG_CONSTANT(I);
   case TargetOpcode::G_GEP:
     return selectG_GEP(I);
+  case TargetOpcode::G_IMPLICIT_DEF:
+    return selectG_IMPLICIT_DEF(I);
   case TargetOpcode::G_INTRINSIC:
     return selectG_INTRINSIC(I, CoverageInfo);
   case TargetOpcode::G_LOAD: