[Bug middle-end/38968] New: Complex matrix product is not vectorized

["dominiq at lps dot ens dot fr" <gcc-bugzilla at gcc dot gnu dot org>]

As shown by the following code, the complex matrix product is not vectorized,
even with the patch in http://gcc.gnu.org/ml/gcc-patches/2009-01/msg01174.html:

program mymatmul
  implicit none
  integer, parameter :: kp = 4
  integer, parameter :: n = 2000
  real(kp), dimension(n,n) :: rr, ri
  complex(kp), dimension(n,n) :: a,b,c
  real :: t1, t2
  integer :: i, j, k

  call random_number (rr)
  call random_number (ri)
  a = cmplx (rr, ri)
  call random_number (rr)
  call random_number (ri)
  b = cmplx (rr, ri)

  call cpu_time (t1)

  c = cmplx (0._kp, 0._kp)
  do j = 1, n
     do k = 1, n
        do i = 1, n
           c(i,j) = c(i,j) + a(i,k) * b(k,j)
        end do
     end do
  end do

  call cpu_time (t2)
  write (*,'(F8.4)') t2-t1

end program mymatmul

[ibook-dhum] bug/timing% gfc -m64 -O3 -ffast-math -funroll-loops
-fomit-frame-pointer -ftree-vectorizer-verbose=2 mymatmul_v_c4.f90              
mymatmul_v_c4.f90:22: note: not vectorized: can't calculate alignment for data
ref.
mymatmul_v_c4.f90:15: note: not vectorized: complicated access pattern.
mymatmul_v_c4.f90:15: note: not vectorized: can't calculate alignment for data
ref.
mymatmul_v_c4.f90:12: note: not vectorized: complicated access pattern.
mymatmul_v_c4.f90:12: note: not vectorized: can't calculate alignment for data
ref.
mymatmul_v_c4.f90:1: note: vectorized 0 loops in function.

The real corresponding code is vectorized.


-- 
           Summary: Complex matrix product is not vectorized
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dominiq at lps dot ens dot fr
 GCC build triplet: i686-apple-darwin9
  GCC host triplet: i686-apple-darwin9
GCC target triplet: i686-apple-darwin9


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38968