[Bug tree-optimization/31040] New: unroll/peel loops not aggressive enough
jv244 at cam dot ac dot uk
gcc-bugzilla@gcc.gnu.org
Mon Mar 5 09:11:00 GMT 2007
Looking at the asm for the program below, there plenty of loops left after
compiling with
> gfortran -S -march=native -O3 -funroll-loops -funroll-all-loops -fpeel-loops test.f90
or any combination of these options. A full unrolling (and in that case a
return of the value 3) would be possible and much faster.
> cat test.f90
INTEGER FUNCTION lxy()
lxy=0
DO lxa=0,1
DO lxb=0,0
DO lya=0,1-lxa
DO lyb=0,0-lxb
lxy=lxy+1
ENDDO
ENDDO
ENDDO
ENDDO
END FUNCTION
write(6,*) lxy()
END
--
Summary: unroll/peel loops not aggressive enough
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jv244 at cam dot ac dot uk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31040
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