GCC no longer synthesizing v2sf operations from v4sf operations?

[Richard Guenther]

Hi!

For

typedef float v4sf __attribute__((vector_size(16)));
void foo(v4sf *a, v4sf *b, v4sf *c)
{
        *a = *b + *c;
}

we no longer (since 4.0) synthesize v2sf (aka sse) operations
for f.i. -march=athlon (not that we were too successful at this
in 3.4 - we generated horrible code instead).  Instead for !sse2
architectures we generate standard i387 FP code (with some
unnecessary temporaries, but reasonably well).

Does this mean the generic manual vectorization with +-* experiment
has failed?  I.e. are we really supposed to use ?mmintrin.h and friends,
or of course rely on auto-vectorization?

Thanks for clarification,
Richard.

--
Richard Guenther <richard dot guenther at uni-tuebingen dot de>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/