[Bug tree-optimization/55022] [4.8 Regression] air.f90 is miscompliled with -m64 -O2 -fgraphite-identity after revision 190619

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55022



--- Comment #12 from Dominique d'Humieres <dominiq at lps dot ens.fr> 
2013-02-07 15:11:23 UTC ---

If I replace the loop

      DO i = Spx , Epx

         vn1 = U(i,Apy)*NX1(i) + V(i,Apy)*NY1(i)

         P(i,Apy) = P(i,Apy)/DEXP(GMA*vn1/AS1(i))

         U(i,Apy) = 0.0

         V(i,Apy) = 0.0

         T(i,Apy) = TWX_0

         RHO(i,Apy) = P(i,Apy)*R_0

         AS1(i) = A_0

         E(i,Apy) = E_0

         U1(i,Apy) = RHO(i,Apy)

         U2(i,Apy) = 0.0

         U3(i,Apy) = 0.0

         U4(i,Apy) = RHO(i,Apy)*E_0

      ENDDO



with



      DO i = Spx , Epx

         vn1 = GMA*(U(i,Apy)*NX1(i) + V(i,Apy)*NY1(i))/AS1(i)

         P(i,Apy) = P(i,Apy)/DEXP(vn1)

         RHO(i,Apy) = P(i,Apy)*R_0

         AS1(i) = A_0

         E(i,Apy) = E_0

         U1(i,Apy) = RHO(i,Apy)

         U4(i,Apy) = RHO(i,Apy)*E_0

      ENDDO

      U(Spx:Epx,Apy) = 0.0

      V(Spx:Epx,Apy) = 0.0

      T(Spx:Epx,Apy) = TWX_0

      U2(Spx:Epx,Apy) = 0.0

      U3(Spx:Epx,Apy) = 0.0



Then the test does not abort with NaNs, but the result seems wrong:



        1729  0.40924060378447885     

        1737  0.41934356330600248     



compared to



        1729  0.40411964185599653     

        1737  0.41528583240265665