http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38306
Joost VandeVondele <Joost.VandeVondele at pci dot uzh.ch> changed:
What |Removed |Added
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Last reconfirmed|2011-02-20 19:01:16 |2011-09-09 19:01:16
--- Comment #24 from Joost VandeVondele <Joost.VandeVondele at pci dot uzh.ch>
2011-09-09 19:06:50 UTC ---
checked again current trunk, the situation remains that -O2 is much faster than
-O3:
> gfortran -O2 -march=native -funroll-loops -ffast-math -ftree-vectorize
> pr38306.f90 ; ./a.out
Time for evaluation [s]: 2.830
> gfortran -O3 -march=native -funroll-loops -ffast-math -ftree-vectorize
> pr38306.f90 ; ./a.out
Time for evaluation [s]: 4.593
The issue is that at -O3 the subroutine PD2VAL is not vectorized, while it is
at -O2.
