[Bug fortran/77648] Setting conversion to a integer to double to 0 3/4 through a loop

[raynman4451 at tamu dot edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77648

--- Comment #2 from Raymond Fontenot <raynman4451 at tamu dot edu> ---
Created attachment 39650
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39650&action=edit
Test Case for Bug

I've attached a test case for this. The code will produce the incorrect
polynomial function p at the end of the routine for the given parameters. The
code will generate the following polynomial (a 1D Wendland function):
  -0.352E-01            
   0.000E+00 x          
   0.446E-01 x^ 2       
   0.000E+00 x^ 3       
  -0.298E-02 x^ 4       
   0.000E+00 x^ 5       
   0.208E-01 x^ 6       
  -0.476E-01 x^ 7       
   0.521E-01 x^ 8       
  -0.317E-01 x^ 9       
   0.000E+00 x^10       
   0.000E+00 x^11      

The correct output from the code should be:
 -0.451E-04            
   0.000E+00 x          
   0.496E-03 x^ 2       
   0.000E+00 x^ 3       
  -0.298E-02 x^ 4       
   0.000E+00 x^ 5       
   0.208E-01 x^ 6       
  -0.476E-01 x^ 7       
   0.521E-01 x^ 8       
  -0.317E-01 x^ 9       
   0.104E-01 x^10       
  -0.144E-02 x^11   

The bug in question happens in the function (in poly_module.f90)
integrate_poly_indefinite, called in generate_wendland.f90.