Add testcase for PR79966

Add testcase for PR79966

[Jan Hubicka]

Hi,
the testcase triggers problem with inlining heuristics where time is capped and
thus inlining into function makes it look not very cool for inlining further.
This is solved by the profile code reorg and thus the testcase works as expected
now.

regtested x86_64-linux, comitted.

	PR middle-end/79966
	* gfortran.dg/pr79966.f90: New testcase
Index: testsuite/gfortran.dg/pr79966.f90
===================================================================
--- testsuite/gfortran.dg/pr79966.f90	(revision 0)
+++ testsuite/gfortran.dg/pr79966.f90	(working copy)
@@ -0,0 +1,112 @@
+! { dg-do compile }
+! { dg-options "-O2 -fpeel-loops -finline-functions -fipa-cp-clone -fdump-ipa-inline-details" }
+
+module TensorProducts
+  use, intrinsic :: iso_fortran_env
+
+  implicit none
+
+  integer, parameter :: dp = real64 ! KIND for double precision
+
+  type Vect3D
+    real(dp) :: x, y, z
+  end type
+
+contains
+
+  type(Vect3D) pure function MySum(array)
+    type(Vect3D), intent(in) :: array(:,:)
+
+    mysum = Vect3D(sum(array%x), sum(array%y), sum(array%z))
+  end function
+
+  pure subroutine GenerateGrid(N, M, width, height, centre, P)
+    integer,      intent(in)  :: N, M
+    real(dp),     intent(in)  :: width, height
+    type(Vect3D), intent(in)  :: centre
+    type(Vect3D), intent(out) :: P(N, M)
+    real(dp)                  :: x(N), y(M)
+    integer                   :: i, j
+
+    x = ([( i, i = 0, N-1 )] * width/(N-1)) - (width / 2) + centre%x
+    y = ([( j, j = 0, M-1 )] * height/(M-1)) - (height / 2) + centre%y
+    do concurrent (i = 1:N)
+      do concurrent (j = 1:M)
+        P(i, j) = Vect3D(x(i), y(j), centre%z)
+      end do
+    end do
+    P(2:3,2:3)%z = P(2:3,2:3)%z + 1.0_dp*reshape([2,1,1,-2], [2,2])
+  end subroutine
+
+  type(Vect3D) pure function TP_SUM(NU, D, NV) result(tensorproduct)
+    ! (NU) D (NV)^T, row * matrix * column
+    ! TODO (#6): TensorProduct: Investigate whether using DO loops triggers a temporary array.
+    ! copied from Surfaces
+    real(dp),     intent(in) :: NU(4), NV(4)
+    type(Vect3D), intent(in) :: D(4,4)
+    integer                  :: i, j
+    type(Vect3D)             :: P(4,4)
+
+    do concurrent (i = 1:4)
+      do concurrent (j = 1:4)
+        P(i,j)%x = NU(i) * D(i,j)%x * NV(j)
+        P(i,j)%y = NU(i) * D(i,j)%y * NV(j)
+        P(i,j)%z = NU(i) * D(i,j)%z * NV(j)
+      end do
+    end do
+    tensorproduct = MySum(P)
+  end function
+
+  subroutine RandomSeed()
+    integer                                 :: seed_size, clock, i
+    integer,              allocatable, save :: seed(:)
+
+    if (.not. allocated(seed)) then
+      call random_seed(size=seed_size)
+      allocate(seed(seed_size))
+      call system_clock(count=clock)
+      seed = clock + 37 * [( i -1, i = 1, seed_size )]
+      call random_seed(put=seed)
+    end if
+  end subroutine
+
+  subroutine RunTPTests()
+    type(Vect3D)       :: tp, P(4,4)
+    integer, parameter :: i_max = 10000000
+    real(dp)           :: NU(4,i_max), NV(4,i_max)
+    real(dp)           :: sum
+    real               :: t(2)
+    integer            :: i
+
+!    print *, 'This code variant uses explicit %x, %y and %z to represent the contents of Type(Vect3D).'
+    call GenerateGrid(4, 4, 20.0_dp, 20.0_dp, Vect3D(0.0_dp,0.0_dp,20.0_dp), P)
+    call RandomSeed()
+!    call cpu_time(t(1))
+    do i = 1, 4
+      call random_number(NU(i,:))
+      call random_number(NV(i,:))
+    end do
+!    call cpu_time(t(2))
+!    print *, 'Random Numbers, time:  ', t(2)-t(1)
+    sum = 0.0
+    call cpu_time(t(1))
+    do i = 1, i_max
+      tp = TP_SUM(NU(:,i), P(1:4,1:4), NV(:,i))
+      sum = sum + tp%x
+    end do
+    call cpu_time(t(2))
+    print *, 'Using SUM, time:       ', t(2)-t(1)
+    print *, 'sum =', sum
+  end subroutine
+
+  end module
+
+  program Main
+  use TensorProducts
+
+  implicit none
+
+  call RunTPTests()
+  end program
+
+! { dg-final { scan-ipa-dump "Inlined tp_sum into runtptests" "inline" } }