http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53676
--- Comment #13 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-08-22 08:46:54 UTC --- (In reply to comment #12) > I've been doing research into LLVM 3.1 and other GCC versions. LLVM 3.1 > correctly eliminate the (near) empty loop, and their current trunk does not > regress like 4.7 has. > > Is the trunk patch coupled to other changes that are too invasive for 4.7? I'm > confused and curious about what optimization regressions are serious enough to > warrant a back port, if any. No, it's only the commit referenced in this PR. No optimization regressions warrant a backport as they always come with the risk of regressing something worse than performance. Trivial restoring of old behavior might be worth backporting but the patch introduces a completely new non-trivial transform into a core analysis engine that is shared among many passes.
