https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63986
Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |ebotcazou at gcc dot gnu.org
--- Comment #4 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> I suppose RTL CSE cannot CSE flag register sets...?
Yes, it can, if you define
-- Target Hook: bool TARGET_FIXED_CONDITION_CODE_REGS (unsigned int
*P1, unsigned int *P2)
On targets which do not use `(cc0)', and which use a hard register
rather than a pseudo-register to hold condition codes, the regular
CSE passes are often not able to identify cases in which the hard
register is set to a common value. Use this hook to enable a
small pass which optimizes such cases. This hook should return
true to enable this pass, and it should set the integers to which
its arguments point to the hard register numbers used for
condition codes. When there is only one such register, as is true
on most systems, the integer pointed to by P2 should be set to
`INVALID_REGNUM'.
