[Bug tree-optimization/30038] New: Call to sin(x), cos(x) should be transformed to sincos(x)

["burnus at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

See also: http://gcc.gnu.org/ml/fortran/2006-12/msg00000.html

Tim Prince's analysis why ifort needs 8.77s and gfortran 12.16s for one
program:

"My copy of gfortran makes separate scalar calls to sin and cos, where ifort
makes a vector sincos call. 2 seconds to be gained there"

In the Fortran program below, a there is a call to the same argument with sin
and with cos. The resulting
  gfortran -msse3 -march=opteron -ffast-math -O3 -c -fdump-tree-optimized
shows
  pretmp.56 = __builtin_sinf (pretmp.80);
  pretmp.86 = __builtin_cosf (pretmp.80);
Using sincos should be faster.


Fortran program:

subroutine
test(number_of_sample_points,radius,coefficient,radius_of_curvature,spin_frequency,time,tmp)
  implicit none
  integer :: number_of_sample_points
  real, parameter   :: twopi = 6.28319
  integer :: n
  real :: radius(number_of_sample_points), coefficient, radius_of_curvature, &
          spin_frequency,time,tmp(2,number_of_sample_points)
  do n = 1, number_of_sample_points
    coefficient = (radius(n) / radius_of_curvature) * sin(twopi *            &
                                        spin_frequency * time)
    tmp(1,n) = coefficient
    coefficient = twopi * spin_frequency * (radius(n) /       &
                                     radius_of_curvature) * cos(twopi *      &
                                         spin_frequency * time)
    tmp(2,n) = coefficient
  end do
end subroutine


-- 
           Summary: Call to sin(x), cos(x) should be transformed to
                    sincos(x)
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30038