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i386/x86-64 UNSPEC_NOP usage
- From: "Jan Beulich" <JBeulich at novell dot com>
- To: "Jan Hubicka" <jh at suse dot de>
- Cc: <gcc at gcc dot gnu dot org>
- Date: Fri, 18 Jun 2004 11:22:25 +0200
- Subject: i386/x86-64 UNSPEC_NOP usage
Would you be able to explain what UNSPEC_NOP is really good for. Since
it's being used only for very few insns, it would seem that if it's
required at all the problem might lie somewhere else. While I'm trying
to fix various inconsistencies in the MMX/SSE support, I'd like to also
do away with some of the superfluous builtins. While for SSE2 the
logicals don't have this set (and thus can be made, by removing their
sse_ prefixes, generic insns that can be recognized also for operations
on vector operands without using builtin functions), the MMX logicals
have this set and I would thus be unsure whether this conflicts in some
way with other expectations the compiler may have elsewhere,
consequently putting under question whether the mmx_ prefixes can also
safely be removed.
Thanks, Jan