[Bug middle-end/40106] [4.4/4.5 Regression] Time increase for the Polyhedron test air.f90 due to bad optimization

[dominiq at lps dot ens dot fr]

------- Comment #31 from dominiq at lps dot ens dot fr  2009-09-03 11:20 -------
More reduced nonfunctional (invalid) test to show the problem:

      IMPLICIT REAL*8(a-H,O-Z)
      PARAMETER (NX=150,NY=150)
      DIMENSION NPX(30), FV2(NX,NY), T(NX,NY), dtt(NX,NY)

      do it = 1, 2000

         DO i = 1 , MXPx
            DO j = 1 , MXPy
               FV2(i,j) = T(i,j)**1.5
           ENDDO
         ENDDO

         DO ix = 1 , NDX
            maxx = maxx + NPX(ix) + 1
            DO iy = 1 , NDY
               DO i = minx , maxx
                  DO j = miny , maxy
                     dtt(i,j) = dtd
                  ENDDO
               ENDDO
               miny = miny + NPX(iy) + 1
            ENDDO
         ENDDO

      end do

      WRITE (7,*) MXPx , MXPy
      END

[ibook-dhum] test/dbg_air% gfc -S -m64 -O2 -funsafe-math-optimizations
air_red.f90
[ibook-dhum] test/dbg_air% grep pow air_red.s
        call    _pow
[ibook-dhum] test/dbg_air% gfc -S -m64 -O2 -funsafe-math-optimizations
-fno-strict-overflow air_red.f90
[ibook-dhum] test/dbg_air% grep pow air_red.s
[ibook-dhum] test/dbg_air% 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40106