[Bug tree-optimization/14741] graphite with loop blocking and interchanging doesn't optimize a matrix multiplication loop

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=14741

--- Comment #35 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
I get

[Book15] f90/bug% /opt/gcc/gcc6p-227264p1/bin/gfortran -Ofast pr14741.f90
-floop-interchange -march=native -Wa,-q                                    
[Book15] f90/bug% time a.out
  0.48728300000000002        10.239999999999826     
0.491u 0.006s 0:00.50 98.0%     0+0k 0+0io 0pf+0w
[Book15] f90/bug% /opt/gcc/gcc6p-227383p1/bin/gfortran -Ofast pr14741.f90
-floop-interchange -march=native -Wa,-q                                    
[Book15] f90/bug% time a.out
   1.4271590000000001        10.239999999999826     
1.430u 0.008s 0:01.44 99.3%     0+0k 0+0io 0pf+0w

i.e., r227264 (or 4.8, 4.9, and 5.2) is ~3 time faster than r227383.