[Bug fortran/29648] New: Inline

[Bug fortran/29648] New: Inline

[P dot Schaffnit at access dot rwth-aachen dot de]

As can be found at http://gcc.gnu.org/ml/fortran/2005-07/msg00286.html

GFortran doesn't do inlining: unfortunately I cannot do it, and I don't know
how hard this would be, but this would certainly help a lot with several codes
I know...


-- 
           Summary: Inline
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: P dot Schaffnit at access dot rwth-aachen dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648

[Bug fortran/29648] Inlining only done for contained procedures

[pault at gcc dot gnu dot org]

------- Comment #1 from pault at gcc dot gnu dot org  2006-10-31 05:34 -------
As the link says, inlining is implemented for contained procedures.  I have
changed the summary to reflect this.


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pault at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-10-31 05:34:33
               date|                            |
            Summary|Inline                      |Inlining only done for
                   |                            |contained procedures


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648

[Bug fortran/29648] Inlining only done for contained procedures

[P dot Schaffnit at access dot rwth-aachen dot de]

------- Comment #2 from P dot Schaffnit at access dot rwth-aachen dot de  2006-10-31 09:13 -------

Right!

Thanks!


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648

[Bug fortran/29648] Inlining only done for contained procedures

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
           Severity|normal                      |minor
           Keywords|                            |missed-optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648

[Bug fortran/29648] Inlining only done for contained procedures

[P dot Schaffnit at access dot rwth-aachen dot de]

-- 

P dot Schaffnit at access dot rwth-aachen dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|minor                       |enhancement


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648

[Bug fortran/29648] Inlining only done for contained procedures

[bdavis at gcc dot gnu dot org]

------- Comment #3 from bdavis at gcc dot gnu dot org  2007-12-01 02:24 -------
in case someone does not know what a contained procedure is (i sure didn't
without getting out the Metcalf and Reid book), below is an example:

       program fred
       integer j
       j = 0
       call a(j)
       print*,j
       contains
       subroutine a(i)
       integer i
       i = i +2
       end subroutine a
       end program fred

compile it with no optimization and look at the assembler code, then compile it
with -O2, the subroutine is inlined by gfortran.

not really relevant to this PR, but something I learned and verified, which
might be of use.

--bud


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648

[Bug fortran/29648] Inlining only done for contained procedures

[dominiq at lps dot ens dot fr]

------- Comment #4 from dominiq at lps dot ens dot fr  2007-12-03 07:45 -------
The code in comment #3 is indeed inlined, but some cases are not. For instance
if you compile the polyhedron test 'channel' with -O3 -ffast-math
-funroll-loops and grep for _ddx, you get:

_ddx.837:
        call    _ddx.837
        call    _ddx.837

If you apply the following patch to channel.f90, i.e., do the inlining
yourself,

--- channel.f90 2005-10-11 22:53:32.000000000 +0200
+++ chan.v2.f90 2007-11-29 21:30:25.000000000 +0100
@@ -145,10 +145,22 @@

     ! ------ interior calculations ------ !

-    dudx = ddx(u(:,:,mid))
-    dvdy = ddy(v(:,:,mid))
-    dhdx = ddx(h(:,:,mid))
-    dhdy = ddy(h(:,:,mid))
+    dudx(2:M-1,:) = u(3:M,: ,mid)-u(1:M-2,: ,mid)    ! interior points
+    dudx(1,:) = 2*(u(2,: ,mid)-u(  1,: ,mid))
+    dudx(M,:) = 2*(u(M,: ,mid)-u(M-1,: ,mid))
+    
+    dvdy(:,2:N-1) = v(:,3:N ,mid)-v(:,1:N-2 ,mid)    ! interior points
+    dvdy(:,1) = 2*(v(:,2 ,mid)-v(:,  1 ,mid))
+    dvdy(:,N) = 2*(v(:,N ,mid)-v(:,N-1 ,mid))
+
+    dhdx(2:M-1,:) = h(3:M,: ,mid)-h(1:M-2,: ,mid)    ! interior points
+    dhdx(1,:) = 2*(h(2,: ,mid)-h(  1,: ,mid))
+    dhdx(M,:) = 2*(h(M,: ,mid)-h(M-1,: ,mid))
+
+    dhdy(:,2:N-1) = h(:,3:N ,mid)-h(:,1:N-2 ,mid)    ! interior points
+    dhdy(:,1) = 2*(h(:,2 ,mid)-h(:,  1 ,mid))
+    dhdy(:,N) = 2*(h(:,N ,mid)-h(:,N-1 ,mid))
+

     u(2:M-1,1:N,new) = u(2:M-1,1:N,old) &               ! interior u points
         +2.d0*dt*f(2:M-1,1:N)*v(2:M-1,1:N,mid) &
@@ -234,38 +246,6 @@
                 0.5*(v(i,j,mid)+v(i,j-1,mid))

 !------------------------------------------------------------
-contains
-!------------------------------------------------------------
-    function ddx(array)
-    implicit double precision (a-h,o-z)
-    double precision::          array(:,:)
-    double precision::          ddx(size(array,dim=1),size(array,dim=2))
-
-    I = size(array,dim=1)
-    J = size(array,dim=2)
-
-    ddx(2:I-1,1:J) = array(3:I,1:J)-array(1:I-2,1:J)    ! interior points
-
-    ddx(1,1:J) = 2*(array(2,1:J)-array(  1,1:J))
-    ddx(I,1:J) = 2*(array(I,1:J)-array(I-1,1:J))
-
-    end function ddx
-
-    function ddy(array)
-    implicit double precision (a-h,o-z)
-    double precision::          array(:,:)
-    double precision::          ddy(size(array,dim=1),size(array,dim=2))
-
-    I = size(array,dim=1)
-    J = size(array,dim=2)
-
-    ddy(1:I,2:J-1) = array(1:I,3:J)-array(1:I,1:J-2)    ! interior points
-
-    ddy(1:I,1) = 2*(array(1:I,2)-array(1:I,  1))
-    ddy(1:I,J) = 2*(array(1:I,J)-array(1:I,J-1))
-
-    end function ddy
-!------------------------------------------------------------
 end program sw

 !------------------------------------------------------------

the timing on an Intel Core2Duo 2.16Ghz goes from 4s to 2.2s.

So my question is: what are the rules applied by GCC for the inlining? I
understand that with -Os, one rule is that inlining must not increase the code
size, but what happened in the case of channel.f90 with -O3?


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648

[Bug fortran/29648] Inlining only done for contained procedures

[steven at gcc dot gnu dot org]

------- Comment #5 from steven at gcc dot gnu dot org  2007-12-03 10:13 -------
Inlining is driven by heuristics.  See ipa-inline.c.  Heuristics cannot be
perfect for all applications, of course.  The current tuning of the heuristics
is based on SPEC2k scores on Opteron, i.e. mostly for programs written in C and
C++.  Maybe for Fortran the current heuristics do not lead to the best possible
results.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648

[Bug fortran/29648] Inlining only done for contained procedures

[dominiq at lps dot ens dot fr]

------- Comment #6 from dominiq at lps dot ens dot fr  2007-12-03 12:41 -------
Form the gcc manual:

-finline-limit=n
... . The default value of n is 600.  ...

This does not seem accurate: ddx and ddy are inlined for n=318, but not for
n=317 (corresponding respectively to 2.7s and 1.6s for the compile time and
2.5s and 4.1s for the execution time).
Note that with the default settings the compile and execution time are 1.6s and
4.1s. For the patched source they are respectively 1.7s and 2.2s.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648

[Bug fortran/29648] Inlining only done for contained procedures

[fxcoudert at gcc dot gnu dot org]

------- Comment #7 from fxcoudert at gcc dot gnu dot org  2009-05-02 14:31 -------
It's now working with -fwhole-file.


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fxcoudert at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648

[Bug fortran/29648] Inlining only done for contained procedures

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29648