[Bug middle-end/40106] New: Time increase with inlining for the Polyhedron test air.f90

["dominiq at lps dot ens dot fr" <gcc-bugzilla at gcc dot gnu dot org>]

The run time of air.f90 of the Polyhedron test suite takes ~15% more time when
compiled with -fwhole-file than without the option.  I have checked that the
subroutines DERIV(X|Y) are inlined with -finline-limit=100, but not with
-finline-limit=50 (for the later I recover the timing without -fwhole-file).
What I have found very odd is that if I manually inline only a single call (see
below) I get the same timing that with all of them (2*14) inlined. This is the
case for trunk and gfortran 4.4.0, but not for 4.3.3 which gives a slower
executable.


I have inlined 

      SUBROUTINE DERIVX(D,U,Ux,Al,Np,Nd,M)
      IMPLICIT REAL*8(A-H,O-Z)
      PARAMETER (NX=150,NY=150)
      DIMENSION D(NX,33) , U(NX,NY) , Ux(NX,NY) , Al(30) , Np(30)
      DO jm = 1 , M
         jmax = 0
         jmin = 1
         DO i = 1 , Nd
            jmax = jmax + Np(i) + 1
            DO j = jmin , jmax
               uxt = 0.
               DO k = 0 , Np(i)
                  uxt = uxt + D(j,k+1)*U(jmin+k,jm)
               ENDDO
               Ux(j,jm) = uxt*Al(i)
            ENDDO
!
            jmin = jmin + Np(i) + 1
         ENDDO
      ENDDO
      CONTINUE
      END

at line 793 as

!       CALL DERIVX(DX,f4,f4x,ALX,NPX,NDX,MXPy)
      DO jm = 1 , MXPy
         jmax = 0
         jmin = 1
         DO i = 1 , NDX
            jmax = jmax + NPX(i) + 1
            DO j = jmin , jmax
               uxt = 0.
               DO k = 0 , NPX(i)
                  uxt = uxt + DX(j,k+1)*f4(jmin+k,jm)
               ENDDO
               f4x(j,jm) = uxt*ALX(i)
            ENDDO
            jmin = jmin + NPX(i) + 1
         ENDDO
      ENDDO


-- 
           Summary: Time increase with inlining for the Polyhedron test
                    air.f90
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dominiq at lps dot ens dot fr
 GCC build triplet: i686-apple-darwin9
  GCC host triplet: i686-apple-darwin9
GCC target triplet: i686-apple-darwin9


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