SSE, XMM and GMP's configure
tg at gmplib.org
Sat Jan 25 18:15:47 UTC 2014
Our configure logic for excluding XMM register use is flawed. We
should to keep SSE2 availability from XMM availability apart, since a
CPU which supports SSE2 will always handle SSE2+MMX, while XMM requires
operating system support. Now, we suppress use of (some) gcc
sse-related options which trigger bad behaviour (via the acinclude.m4
GMP_GCC_PENTIUM4_SSE2) and in that context check of the OS handles XMM
Limiting that check to that context does not properly suppress assembly
code in sse2 subdirs. Suppressing all that code would actually be
sub-optimal, since some of it might actually stick to MMX regs.
I discovered this problem when running tests on the long-obsolete
It would be nice to clean this up, but I won't have time to work on it
before the release.
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