Debug Info: Bail out of AddMachineRegPiece() if MachineReg is not a

physical register. The call to getMinimalPhysRegClass() later on asserts
on this condition.

llvm-svn: 225852

llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp

@@ -93,6 +93,12 @@ void DwarfExpression::AddMachineRegPiece(unsigned MachineReg,
                                          unsigned PieceSizeInBits,
                                          unsigned PieceOffsetInBits) {
   const TargetRegisterInfo *TRI = getTRI();
+  if (!TRI->isPhysicalRegister(MachineReg)) {
+    // FIXME: We have no reasonable way of handling errors in here.
+    EmitOp(dwarf::DW_OP_nop, "nop (could not find a dwarf register number)");
+    return;
+  }
+
   int Reg = TRI->getDwarfRegNum(MachineReg, false);
 
   // If this is a valid register number, emit it.