[PATCH] Fix assert with copy from global through addrspacecast

[Michele Scandale]

  The suggested name won't be ambiguous, so +1.

  BTW, I don't see the problem, if a non pointer value is passed, an addrspacecast would be illegal because it requires a pointer value, while a bitcast would be valid w.r.t. its constraints.

    Constant *ConstantExpr::getBitCastOrAddrSpaceCast(Constant *S, Type *Ty) {
      assert((CastInst::castIsValid(Instruction::BitCast, S, Ty) ||
              CastInst::castIsValid(Instruction::AddrSpaceCast, S, Ty)) &&
              "Invalid cast");

      unsigned SrcTy = S->getType();
      if (Ty->isPtrOrPtrVectorTy() && DestTy->isPtrOrPtrVectorTy() &&
          SrcTy->getPointerAddressSpace() != Ty->getPointerAddressSpace())
        return getAddrSpaceCast(S, Ty);

      return getBitCast(S, Ty);
    }

  But maybe something like this could just an helper in IRBuilder...

http://llvm-reviews.chandlerc.com/D2205