[Bug target/29953] [SH-4] Perfomance regression in loops. cmp/eq used instead of dt

[christian dot bruel at st dot com]

------- Comment #3 from christian dot bruel at st dot com  2007-04-03 07:43 -------
thank you for reporting this,

There is indeed a data dependency on 'r2' introduced by the cmp/eq instruction,
preventing the mov and the comparaison to be executed in parallel, unlike the
dt on the induction variable.

The use of dt seems to be quite sensitive, I checked on various versions sh-gcc
(3.3.x, 3.4.x) and it was difficult to find one using the correct strategy.
I'll check that issue.

Regards,


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29953