https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107946
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
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Target Milestone|--- |13.0
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Nope, it wasn't supposed to speedup the benchmark but it indeed (with -Ofast)
causes the hot loop kernels to be unswitched.
Btw, do we know if train and ref data align up in these loops?
Btw, with -Ofast on znver2 I didn't observe any change when benchmarking this.
I'm trying to reproduce.
OK, so with -O2 -flto -march=znver2 and FDO I get a runtime of 173s while
adding -fno-unswitch-loops gets me 188s. There's currently no knob to
specifically disable outer loop unswitching so I have to instead patch
that up. With -O2 -flto -funswitch-loops (w/o FDO) I get 178s. I'm going
to add a --param to allow easier reproduction.
