[Patch, fortran] Inline DOT_PRODUCT

[Paul Thomas]

Steven,

:ADDPATCH fortran:

Please find attached a patch to implement dot_product inline.  This 
version includes support for logical types and a corresponding test.  
All dotprod.m4's and the corresponding generated functions have been 
removed.

I note that I did not remember to update the copyright dateline in 
libgfortran/makefile.am - I will do so before I commit the patch.

Whilst I have regtested and all is well, the main purpose of this patch 
is to speed up execution of dot_product for small arrays.  To this end, 
I attach a test program that is not part of the patch but produces the 
results below, on a quiet Athlon1700.  It may be seen that, with -O3, 
the patch removes the function call overhead of ~25-30ns, which is 
highly significant for arrays of sizes below approximately 32.  The 
error on the timing is a few ns and there is a residual overhead, which 
must(?) be the dot_product loop overhead, which is about 15ns.  The 
performance, with the patch, is identical to that of ifort.

It will be seen that I have replaced gfc_conv_expr's with 
gfc_conv_expr_val's and have not, therefore, attached the corresponding 
post blocks to the block enclosed by the loop.  This does not, however, 
change the generated code.

OK for trunk and, whenever, 4.1?

Paul

2006-02-27  Paul Thomas  <pault@gcc.gnu.org>

    * iresolve.c (gfc_resolve_dot_product):  Remove any difference in
    treatment of logical types.
    * trans-intrinsic.c (gfc_conv_intrinsic_dot_product):  New function.
    * libgfortran/Makefile.in: Regenerated.
    * libgfortran/Makefile.am: Remove all references to dotprod.
    * libgfortran/aclocal.m4: Regenerated.
    * libgfortran/m4/dotprodc.m4: Removed.
    * libgfortran/m4/dotprodl.m4: Removed.
    * libgfortran/m4/dotprod.m4: Removed.
    * libgfortran/generated/dotprod_xx.c: All types removed.

2006-02-27  Paul Thomas  <pault@gcc.gnu.org>

    * gfortran.dg/dot_product_logical.f90: New test.

PATCHED:

[prt@localhost dot_product]# /svn-4.2/bin/gfortran  -O3 
-fdump-tree-original dottest.f90;./a.out
DOT_PRODUCT test
   array length        time(ns)

        4               21.50
        8               15.70
       16               56.10
       32              100.20
       64              191.70
      128              372.50
      256              735.60
      512             1459.90
     1024             2908.60

NOT PATCHED:

[prt@localhost dot_product]# export 
LD_LIBRARY_PATH=/svn-4.1/lib:/opt/intel/fc/9.0/lib [prt@localhost 
dot_product]# /svn-4.1/bin/gfortran  -O3 -fdump-tree-original 
dottest.f90;./a.out
DOT_PRODUCT test
   array length        time(ns)

        4               44.60
        8               39.90
       16               80.70
       32              126.30
       64              216.90
      128              398.50
      256              760.50
      512             1489.60
     1024             2936.40
[prt@localhost dot_product]# ifort dottest.f90;./a.out DOT_PRODUCT test
   array length        time(ns)

        4               20.90
        8               18.90
       16               52.70
       32               98.90
       64              189.50
      128              370.90
      256              732.70
      512             1458.40
     1024             2986.90


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