[Bug target/39942] Nonoptimal code - leaveq; xchg %ax,%ax; retq

[jakub at gcc dot gnu dot org]

------- Comment #27 from jakub at gcc dot gnu dot org  2009-05-13 19:08 -------
If inserting the padding isn't worth it for say core2, m_CORE2 could be dropped
from X86_TUNE_FOUR_JUMP_LIMIT, but certainly it would be interesting to see
SPEC numbers backing that up.  Similarly for AMD CPUs, and if on at least one
of these it is beneficial, probably m_GENERIC should keep it, though with far
improved min_insn_size so that it doesn't trigger unnecessarily so often.

Vlad/Honza, could one of you SPEC test say current 4.4 with one (or both of):
http://gcc.gnu.org/ml/gcc-patches/2009-05/msg00702.html
http://gcc.gnu.org/ml/gcc-patches/2009-05/msg00703.html
on top of it (no need to compare clearly unneeded paddings to no paddings,
better compare only somewhat needed paddings against no paddings) compared with
X86_TUNE_FOUR_JUMP_LIMIT cleared for the used CPU?


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
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                 CC|                            |vmakarov at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39942