https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40838
--- Comment #97 from Dzianis Kahanovich <mahatma at eu dot by> ---
No. Looking into gcc/opts.c - "-O3 optimizations" section - line:
{ OPT_LEVELS_3_PLUS, OPT_fvect_cost_model_, NULL, VECT_COST_MODEL_DYNAMIC },
- so, for -O3 it's "dynamic". Then, RTFM, "cheap" more cares about aligning.
But anymore, I not try to rebuild 32bit "world" without ANY workaround, so all
still dirty ;)
PS For some options configuration behaviour still non-linear, so queryng "gcc
-Q ..." still unsafe to check some defaults...
(In reply to Viktor Ostashevskyi from comment #96)
> Honestly, I don't see how your compiler flags could help. cost-model=cheap
> is default, data-alignment doesn't change incoming stack alignment.
>
> ср, 15 січ. 2020, 14:31 користувач mahatma at eu dot by <
> gcc-bugzi...@gcc.gnu.org> пише:
>
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40838
> >
> > --- Comment #95 from Dzianis Kahanovich <mahatma at eu dot by> ---
> > Just FYI. Novadays, on my Thinkpad tablet with Atom (32 bit userspace
> > Gentoo),
> > I globally replace patch/-mstackrealign to "-fvect-cost-model=cheap
> > -fsimd-cost-model=cheap -malign-data=cacheline" and all works fine for -O3
> > +.
> > (This is dirty example, as cacheline for some old SSE CPUs are different,
> > etc).
> >
> > --
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