X86 Built-in Functions

[Falk Hueffner]

Jay Groven <grovenjl@rose-hulman.edu> writes:

> All of the SSE functions listed in the gcc manual return a value, i.e. we have
> 
> v4sf __builtin_ia32_mulps (v4sf, v4sf)
> 
> which returns the component-wise product of the two given vectors.  However, 
> the actual sse instruction mulps is accumulator-based.  This seems to make 
> gcc use quite a few temp registers when you call mulps, since it's trying to 
> give a return value for an instruction that doesn't work that way.

The register allocator should do this for you. Do you have concrete
code where this doesn't work?

-- 
	Falk