On 19/07/11 16:06, DJ Delorie wrote:
What's the point of the second define insn? The first insn seems to
take us from expansion to asm generation so I can't see where the
second one will come into play except in an expansion after reload
but that doesn't happen, right?
IIRC it has to do with optimizing away compare instructions. Which
pattern you need depends on whether the flags will get used by a
conditional branch or not.
So, this seems to have to do with the post-reload comparison
optimization pass Richard mentioned. But I am still confused as to how
GCC matches them. Is *_flags any special name GCC loops for (doubtful)?
--
PMatos
