[Bug fortran/36840] Fortran complex array multiply missed optimization

[kargl at gcc dot gnu dot org]

------- Comment #1 from kargl at gcc dot gnu dot org  2008-07-15 19:03 -------
This would appear to be a middle-end or back-end issue.  Given 
-fdump-tree-original to 4.2.3,  one finds

complex_mult_test (iy, ix, nx)
{
   S.4 = 1;
     while (1)
     {
       if (S.4 > ubound.0) goto L.1; else (void) 0;
       (*iy)[NON_LVALUE_EXPR <S.4> + -1] = (*iy)[NON_LVALUE_EXPR <S.4> + -1]
            * (*ix)[NON_LVALUE_EXPR <S.4> + -1];
       S.4 = S.4 + 1;
     }

If I use 4.4.0, I get

complex_mult_test (complex(kind=8)[0:D.1020] * iy,
     complex(kind=8)[0:D.1017] * ix, integer(kind=4) & nx)
{
      S.4 = 1;
      while (1)
        {
          if (S.4 > ubound.2) goto L.1;
          (*iy)[S.4 + -1] = (*iy)[S.4 + -1] * (*ix)[S.4 + -1];
          S.4 = S.4 + 1;
        }

In either case, gfortran hands the middle-end the complex multiplication.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36840