[PATCH] Add CreatePointerBitCastOrAddrSpaceCast to IRBuilder and co.

[Quentin Colombet]

  Let me be more specific on the proposal.

  I think CastInst::CreatePointerCast can call CastInst::CreatePointerBitCastOrAddrSpaceCast as soon as we handled the PtrToInt part.
  I.e.,
  CastInst *CastInst::CreatePointerCast(Value *S, Type *Ty,
                                        const Twine &Name,
                                        BasicBlock *InsertAtEnd) {
    assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
    assert((Ty->isIntOrIntVectorTy() || Ty->isPtrOrPtrVectorTy()) &&
           "Invalid cast");
    assert(Ty->isVectorTy() == S->getType()->isVectorTy() && "Invalid cast");
    assert((!Ty->isVectorTy() ||
            Ty->getVectorNumElements() == S->getType()->getVectorNumElements()) &&
           "Invalid cast");

    if (Ty->isIntOrIntVectorTy())
      return Create(Instruction::PtrToInt, S, Ty, Name, InsertAtEnd);
  /* ==== Call Your New method instead ==== */
    Type *STy = S->getType();
    if (STy->getPointerAddressSpace() != Ty->getPointerAddressSpace())
      return Create(Instruction::AddrSpaceCast, S, Ty, Name, InsertAtEnd);

    return Create(Instruction::BitCast, S, Ty, Name, InsertAtEnd);
  /* ====== */
  }

  Same thing for the instruction version.

  Moreover, we should do the same for Constant *ConstantExpr::getPointerCast(Constant *S, Type *Ty).

  Again maybe I am missing something, but at first glance, it seems at those points in the code path of XXXPointerCast we have the same restriction, isn’t it?

  Thanks,
  -Quentin

http://llvm-reviews.chandlerc.com/D2598