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[Bug debug/55585] compile time hog at -O1 -fboundscheck -g
- From: "Joost.VandeVondele at mat dot ethz.ch" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 04 Dec 2012 10:43:10 +0000
- Subject: [Bug debug/55585] compile time hog at -O1 -fboundscheck -g
- Auto-submitted: auto-generated
- References: <bug-55585-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55585
--- Comment #4 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> 2012-12-04 10:43:10 UTC ---
Interestingly, the magic switch is -fstrict-aliasing... 20x speedup. for a
Fortran code quite a surprise.
> time gfortran -c -O1 -fbounds-check -g -fstrict-aliasing slow.f90
real 0m11.483s
I think for Fortran -fstrict-aliasing could well be the default at -O1, but
maybe there is an underlying reason why this flag is needed ?