[Bug target/43743] Dumb use of SSE regs for MMX operation

ian at airs dot com gcc-bugzilla@gcc.gnu.org
Mon Apr 19 17:09:00 GMT 2010



------- Comment #4 from ian at airs dot com  2010-04-19 17:08 -------
Staying away from MMX registers is not an option here.  This code is reduced
from some code in Chrome.  Chrome is trying to provide several different
routines which do the same thing but which run on different processors.  The
MMX code is for use on processors which only support MMX.

I've recommended that the compile the code in different source files, although
that is apparently complex for some reason.  In any case, this seems to me like
a clear bug: using MMX intrinsics should cause the use of MMX registers.  One
simple approach here would be to avoid using the same define_insn for both MMX
and SSE.

If it is not going to be fixed, then it should be documented.  The docs should
say something like "if you use <mmintrin.h>, compile with -mno-sse."


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43743



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