https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64207
Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC| |Joost.VandeVondele at mat dot
ethz
| |.ch
Resolution|--- |FIXED
--- Comment #1 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch>
---
-fopt-info is the replacement for -ftree-vectorizer-verbose, the latter is
deprecated
for example try -fopt-info-vec-missed or -fopt-info-all
best is to keep the part to analyze rather simple, since it generates a lot of
info that isn't always easy to understand:
> cat t.f90
subroutine s(a,b,c)
real, dimension(1024, 1024) :: a,b,c
do i=1,1024
do j=1,1024
c(i,j) = a(j,i)*b(j,i)
end do
end do
end subroutine
> gfortran -c -O3 -march=native -ffast-math -fopt-info-vec-missed t.f90
t.f90:3:0: note: not vectorized: complicated access pattern.
t.f90:3:0: note: bad data access.
t.f90:4:0: note: not consecutive access *c_19(D)[_10] = _18;
t.f90:4:0: note: not vectorized: complicated access pattern.
t.f90:4:0: note: bad data access.
[...]
> cat t.f90
subroutine s(a,b,c)
real, dimension(1024, 1024) :: a,b,c
do i=1,1024
do j=1,1024
c(j,i) = a(j,i)*b(j,i)
end do
end do
end subroutine
> gfortran -c -O3 -march=native -ffast-math -fopt-info-vec t.f90
t.f90:4:0: note: loop vectorized
t.f90:4:0: note: loop peeled for vectorization to enhance alignment
