https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113701
Roger Sayle <roger at nextmovesoftware dot com> changed:
What |Removed |Added
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See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=106518
--- Comment #5 from Roger Sayle <roger at nextmovesoftware dot com> ---
I like Uros' patch in comment #2. There have been so many incremental changes
and improvements to x86 TImode and register allocation, that this legacy
heuristic (workaround?) is not only no longer useful, but it actually hurts
register allocation. *cmp<dwi>_doubleword appears to be the only (remaining?)
place this idiom is used.
Additionally, I think I've mentioned in the past that it might also be useful
to have a xchg/swap sinking pass, perhaps as part of cprop_hardreg, so that for
example swap followed by swap is eliminated, that swap with one destination
REG_DEAD is transformed into mov, etc. Swap/xchg is almost always just hard
register renaming, so these should often be eliminatable, but the abstraction
is useful to allow this to happen.
