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
