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Re: [PATCH] Re: Rewrite i386 string operation expansion
On 11/30/06, Jan Hubicka <jh@suse.cz> wrote:
> >> > Also crashes for -march=pentium, -march=k6 and -march=nocona.
> >>
> >> Attached patch fixes this failure. Bootstrapped on i686-pc-linux-gnu.
> If there is a better alternative, we still use it.
Actually I would probably go for rep_prefix_4_byte/rep_prefix_8_byte
when not optimizing for size and for rep_prefix_1_byte otherwise. The
full sized REP instruction is usually significantly faster in most
cases and it is what kernel folks do (and those are about the main users of
full inlining here).
Jan,
my proposed patch was more or less a band-aid for povray compilation
failure (-march=pentium4 -minline-all-stringops). However, I've
noticed that this proposed "solution" actually introduced a bit
(~1.4%) longer execution times on my povray test, perhaps due to the
reason you outlined above.
There is a fixup code for TARGET_INLINE_ALL_STRINGOPS below, but it is
never reached due to the assert that triggers in pentium4 case. I
guess that the correct solution is more complex than the one I
proposed.
Uros.