[PATCH] Allow casts of mixed-size same-arity vectors

Stephen Canon scanon at apple.com
Wed Sep 11 15:31:09 PDT 2013


On Sep 11, 2013, at 3:29 PM, Hal Finkel <hfinkel at anl.gov> wrote:

> ----- Original Message -----
>> ----- Original Message -----
>>> Hal —
>>> 
>>> Am I understanding this correctly:
>>> 
>>> 	vector4float x;
>>> 	vector4int16 y = (vector4int16)x; // this is a conversion
>>> 	vector4int32 z = (vector4int32)x; // this is a bitcast
>>> 
>>> This seems confusing in the extreme.
> 
> On the other hand, I don't really like the implied int-to-float bitcast semantics. Maybe it would be better to just add a warning for this case. What do you think?

bitcast semantics for vector casts are an essential tool for SIMD programming.  Essentially all warnings generated would be false positives.

– Steve
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