[Bug tree-optimization/57534] [6/7/8 Regression]: Performance regression versus 4.7.3, 4.8.1 is ~15% slower

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57534

--- Comment #29 from amker at gcc dot gnu.org ---
(In reply to Jeffrey A. Law from comment #28)
> BTW, ISTM that we need Bin to chime in on the complexity of improving this
> in IVOPTS -- ie, is it gcc-8 or gcc-9 material.  If the latter, then we
> should adjust the target milestone.

Yes, it's more like a GCC9 stuff.
For the record, I think this could be generalized to cover addressing mode
issue revealed by PR84037.  That is, not only non-iv addresses, but also
addresses after iv_rewrite could be refined for best selection of addressing
mode.