[Bug fortran/22572] New: Double occurrence of matmul intrinsic not optimised

["schnetter at aei dot mpg dot de" <gcc-bugzilla at gcc dot gnu dot org>]

GNU Fortran 95 (GCC 4.1.0 20050715 (experimental)), when run with the options  
-Wall -O3 -march=pentium4 -S, optimises one of the two calls to the sin  
intrinsic away in the following function:  
  
function optsin (x)  
  implicit none  
  double precision :: optsin  
  double precision, intent(in) :: x  
  optsin = sin(x) / (1 + sin(x))  
end function optsin  
  
In the "equivalent" function  
  
function optmatmul (a, b, ni, nj)  
  implicit none  
  integer, intent(in) :: ni, nj  
  double precision :: optmatmul(ni, nj)  
  double precision, intent(in) :: a(ni, nj), b(ni, nj)  
  optmatmul = matmul(a, b) / (1 + matmul(a, b))  
end function optmatmul  
  
the two calls to matmul both remain present in the assembler output, although  
they are known to return the same result.

-- 
           Summary: Double occurrence of matmul intrinsic not optimised
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: schnetter at aei dot mpg dot de
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22572