[PATCH] Add __builtin_convertvector

[Eli Friedman]

On Mon, Sep 16, 2013 at 8:41 PM, hfinkel at anl.gov <hfinkel at anl.gov> wrote:

>
>
> ================
> Comment at: include/clang/AST/Expr.h:3474
> @@ +3473,3 @@
> +/// vector type of the same arity.
> +class ConvertVectorExpr : public Expr { // Should this be an
> ExplicitCastExpr?
> +private:
> ----------------
> Eli Friedman wrote:
> > No, this should not be a CastExpr.
> Okay; I copied this comment from the AsTypeExpr node, so we should
> probably remove it from there too.
>

Okay.


>
> ================
> Comment at: lib/CodeGen/CGExprScalar.cpp:1011
> @@ +1010,3 @@
> +      Res = Builder.CreateIntCast(Src, DstTy, InputSigned, "conv");
> +    else if (InputSigned)
> +      Res = Builder.CreateSIToFP(Src, DstTy, "conv");
> ----------------
> Eli Friedman wrote:
> > What if the destination type is a bool vector?
> I think bool vectors are explicitly forbidden (in r190721).
>

You can still use the ext_vector_type attribute to get one.


>
> ================
> Comment at: lib/Sema/SemaExpr.cpp:4489
> @@ +4488,3 @@
> +                     << E->getSourceRange());
> +
> +  return Owned(new (Context) ConvertVectorExpr(E, DstTy, VK, OK,
> BuiltinLoc,
> ----------------
> Eli Friedman wrote:
> > You might want to be careful exactly what vector types we accept here...
> but I can't think of anything you actually need to check for, so maybe not.
> I *think* that everything relevant is checked in Sema::BuildExtVectorType
> and HandleVectorSizeAttr (in SemaType.cpp), and so checking that we have a
> vector type should be sufficient.
>
> I could add an assert here just to be on the safe side; something like
> assert(Ty->isBuiltinType() && !Ty->isBooleanType() && (Ty->isIntegerType()
> || Ty->->isRealFloatingType()) && "...");
>

Okay.


>
> ================
> Comment at: lib/Sema/TreeTransform.h:9171
> @@ +9170,3 @@
> +  llvm_unreachable("Cannot transform convertVector expressions yet");
> +}
> +
> ----------------
> Eli Friedman wrote:
> > It would be nice to fix this before committing.
> Agreed; this is another thing coped from the AsTypeExpr code. How can I
> test this?
>
>
This ought to trigger it:

typedef int int_v4 __attribute__((vector_size(16)));
typedef float float_v4 __attribute__((vector_size(16)));
template<typename T> T f(int_v4 x) { return __builtin_convertvector(x, T); }
float_v4 g(int_v4 x) { return f<float_v4>(x); }

-Eli
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20130916/b240bcf9/attachment.html>