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Re: [i386] Replace builtins with vector extensions


On Tue, 9 Apr 2013, Marc Glisse wrote:

On Tue, 9 Apr 2013, Richard Biener wrote:

I seem to remember discussion in the PR(s) that the intrinsics should
(and do for other compilers) expand to the desired instructions even when
the corresponding instruction set is disabled.

emmintrin.h starts with:
#ifndef __SSE2__
# error "SSE2 instruction set not enabled"

Oh, re-reading your post, it looks like you mean we should change the current behavior, not just avoid regressions...

My opinion on the intrinsics is that they are the portable way to use vectors on x86, but they are not equivalent to asm (which people should use if they don't want the compiler looking at their code). Knowingly generating SSE code with -mno-sse is not very appealing.

However, the arguments in:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56298
make sense. I guess I'll forget about this patch.

--
Marc Glisse


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