[PATCH] Make Scalar Replacement of Aggregates use the right opcode for converting from vector-of-int to vector-of-pointer

[Benjamin Kramer]

On 20.09.2013, at 20:55, Tom Roeder <tmroeder at google.com> wrote:

> Index: lib/Transforms/Scalar/SROA.cpp
> ===================================================================
> --- lib/Transforms/Scalar/SROA.cpp	(revision 191100)
> +++ lib/Transforms/Scalar/SROA.cpp	(working copy)
> @@ -1460,6 +1460,22 @@
>      return false;
>    }
>  
> +  if (NewTy->isVectorTy() || OldTy->isVectorTy()) {
> +    // Since the two vectors were checked above to have the same size in bits,
> +    // any two vector types can be converted with bitcast, inttoptr, or
> +    // ptrtotint.
> +    if (NewTy->isVectorTy() && OldTy->isVectorTy())
> +      return true;
> +
> +    // At this point, exactly one of OldTy and NewTy is a vector type.
> +    // The conversion between <n x type*> and any other non-vector type is not
> +    // possible. So, check that the vector type does not have a pointer element
> +    // type.

Not possible is a bit hard in wording, it just needs an intermediate bitcast step through the intptr type.

> +    VectorType *VecTy = cast<VectorType>(OldTy->isVectorTy() ? OldTy : NewTy);
> +    if (VecTy->getElementType()->isPointerTy())
> +      return false;
> +  }
> +
>    return true;
>  }
>  
> @@ -1479,9 +1495,16 @@
>      if (IntegerType *NewITy = dyn_cast<IntegerType>(Ty))
>        if (NewITy->getBitWidth() > OldITy->getBitWidth())
>          return IRB.CreateZExt(V, NewITy);
> -  if (V->getType()->isIntegerTy() && Ty->isPointerTy())
> +  Type *SrcTy = V->getType();
> +  Type *DstTy = Ty;

I think renaming the parameters from the beginning of the function is a good idea, preferably using the same naming scheme (OldTy, NewTy) as canConvertValue. Typing V->getType() all the time is tiresome.

> +  if (VectorType *SrcVecTy = dyn_cast<VectorType>(SrcTy))
> +    SrcTy = SrcVecTy->getElementType();
> +  if (VectorType *DstVecTy = dyn_cast<VectorType>(DstTy))
> +    DstTy = DstVecTy->getElementType();

This could use Type->getScalarType() which returns the element type if it's a vector or the type if it's not. It could also be inlined into the checks below.

- Ben

> +
> +  if (SrcTy->isIntegerTy() && DstTy->isPointerTy())
>      return IRB.CreateIntToPtr(V, Ty);
> -  if (V->getType()->isPointerTy() && Ty->isIntegerTy())
> +  if (SrcTy->isPointerTy() && DstTy->isIntegerTy())
>      return IRB.CreatePtrToInt(V, Ty);
>  
>    return IRB.CreateBitCast(V, Ty);