[HIP] Fix managed variable linkage

Currently managed variables are emitted as undefined symbols, which
causes difficulty for diagnosing undefined symbols for non-managed
variables.

This patch transforms managed variables in device compilation so that
they can be emitted as normal variables.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D96195

lib/IR/ReplaceConstant.cpp

@@ -60,6 +60,7 @@ Instruction *createReplacementInstr(ConstantExpr *CE, Instruction *Instr) {
   case Instruction::PtrToInt:
   case Instruction::IntToPtr:
   case Instruction::BitCast:
+  case Instruction::AddrSpaceCast:
     return dyn_cast<Instruction>(
         Builder.CreateCast((Instruction::CastOps)OpCode, CE->getOperand(0),
                            CE->getType(), CE->getName()));