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

[glisse at gcc dot gnu.org]

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

--- Comment #19 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Aldy Hernandez from comment #16)
> It seems tree-ssa-reassoc.c avoids reassociating most non-bit expressions by
> design (because of signed overflows):
[...]
> So instead of whacking tree-ssa-reassoc.c to handle POINTER_PLUS_EXPR and
> PLUS_EXPR, etc,

There have been suggestions that we should do reassoc after some kind of
lowering, where all integer operations wrap, maybe pointer operations are
replaced with integer operations, etc.