[Bug middle-end/51233] [ipa-iterations] running multiple passes of early IPA on zlib produces more optimal code

[matt at use dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51233

--- Comment #2 from Matt Hargett <matt at use dot net> 2012-08-14 00:26:35 UTC ---
Okay. I filed this bug at your request last year because of your concerns that
some of the improvements seen with multiple iterations might be "papering over"
existing bugs in the optimizers. Does this mean that in this zlib case the
passes are all fine, but multiple iterations legitimately helps?

The original discussion was in the context of Maxim's devirt patches. Would the
approach you mention still allow for the testcases from his proposed patches to
pass? (We can discuss this second question on-list, if you like.)

Thanks for reviving this; we saw dramatic performance improvements with the
4.6-based deliverable we got from Maxim.