[Bug rtl-optimization/31849] [4.2/4.3 Regression] Code size regression caused by fix to PR 31360

[rakdver at gcc dot gnu dot org]

------- Comment #11 from rakdver at gcc dot gnu dot org  2007-05-07 14:25 -------
(In reply to comment #10)
> So this comes down to the orders of passes?  At least that is what is being
> said as far as I can tell (though maybe flow is just too stupid to pull back
> the increment and have it as being free).

About what testcase are you speaking?  As for the first one, I really have no
idea yet what is going on there (all that was written here are just
hypothesis).

As for the second one, the problem is that ivopts do not know about
autoincrements, so it transforms

  something (*src++);
  something (*dest++);
(which is better on autoinc-having architecture)

to

  something (src[i]);
  something (dest[i]);
  i++;

(which would be better if autoinc is not available).

At the moment, I have no intention to teach ivopts about autoinc (since ivopts
need to be rewritten, anyway).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31849