AMDGPU/GlobalISel: Work around a selector crash

Ideally types without a corresponding register class wouldn't reach
here, but we're currently missing some (in particular a 192-bit class
is missing).

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp b/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
index a52816d..f1bb8f3 100644 (file)
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
@@ -1627,6 +1627,8 @@ bool AMDGPUInstructionSelector::selectG_TRUNC(MachineInstr &I) const {
     = TRI.getRegClassForSizeOnBank(SrcSize, *SrcRB, *MRI);
   const TargetRegisterClass *DstRC
     = TRI.getRegClassForSizeOnBank(DstSize, *DstRB, *MRI);
+  if (!SrcRC || !DstRC)
+    return false;
 
   if (!RBI.constrainGenericRegister(SrcReg, *SrcRC, *MRI) ||
       !RBI.constrainGenericRegister(DstReg, *DstRC, *MRI)) {