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[Bug tree-optimization/69042] [6 regression] Missed optimization in ivopts


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69042

--- Comment #9 from amker at gcc dot gnu.org ---
(In reply to amker from comment #8)
> Though adding candidate with offset stripped from base helps this case, it
> causes other regressions which I need to understand.

I can confirm that one major regression on AArch64 for spec2k is in 173.applu. 
The root cause is this change increases candidate number.  The number exceeds
the default "--param iv-consider-all-candidates-bound=30".  It can be resolved
by increasing this param.
Other regressions seem false alarms, I couldn't reproduce it.

There are some small improvements in other cases, overall the spec2k perf isn't
changed on AArch64.  I will check spec2k6 and will send the patch if there is
no regression either.
And can we increase the param bound a little now (or in GCC 7)?

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