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| author | Toon Moene <toon@moene.indiv.nluug.nl> | 2002-11-21 00:22:50 +0100 |
|---|---|---|
| committer | Toon Moene <toon@gcc.gnu.org> | 2002-11-20 23:22:50 +0000 |
| commit | 02f0f531d49fc0c0d6b91692fe49b23a0cc9e2bf (patch) | |
| tree | 30958b40273c9de178ef061a03f4fb29b2cc22ff | |
| parent | 27e58a706fa38f55d87610ed6424523c0ea50bd4 (diff) | |
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invoke.texi: Explain the purpose of -fmove-all-movables...
2002-11-20 Toon Moene <toon@moene.indiv.nluug.nl>
* invoke.texi: Explain the purpose of -fmove-all-movables,
-freduce-all-givs and -frerun-loop-opts better.
From-SVN: r59323
| -rw-r--r-- | gcc/f/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/f/invoke.texi | 27 |
2 files changed, 16 insertions, 16 deletions
diff --git a/gcc/f/ChangeLog b/gcc/f/ChangeLog index 2142b4c..8b378cf 100644 --- a/gcc/f/ChangeLog +++ b/gcc/f/ChangeLog @@ -1,3 +1,8 @@ +2002-11-20 Toon Moene <toon@moene.indiv.nluug.nl> + + * invoke.texi: Explain the purpose of -fmove-all-movables, + -freduce-all-givs and -frerun-loop-opts better. + 2002-11-19 Toon Moene <toon@moene.indiv.nluug.nl> PR fortran/8587 diff --git a/gcc/f/invoke.texi b/gcc/f/invoke.texi index f07df02..58710ce 100644 --- a/gcc/f/invoke.texi +++ b/gcc/f/invoke.texi @@ -1656,26 +1656,21 @@ but possibly slower. @item -fno-rerun-loop-opt @cindex -fno-rerun-loop-opt option @cindex options, -fno-rerun-loop-opt -@emph{Version info:} -These options are not supported by -versions of @command{g77} based on @command{gcc} version 2.8. +In general, the optimizations enabled with these options will lead to +faster code being generated by GNU Fortran; hence they are enabled by default +when issuing the @command{g77} command. -Each of these might improve performance on some code. +@option{-fmove-all-movables} and @option{-freduce-all-givs} will enable +loop optimization to move all loop-invariant index computations in nested +loops over multi-rank array dummy arguments out of these loops. -Analysis of Fortran code optimization and the resulting -optimizations triggered by the above options were -contributed by Toon Moene (@email{toon@@moene.indiv.nluug.nl}). +@option{-frerun-loop-opt} will move offset calculations resulting +from the fact that Fortran arrays by default have a lower bound of 1 +out of the loops. These three options are intended to be removed someday, once -they have helped determine the efficacy of various -approaches to improving the performance of Fortran code. - -Please let us know how use of these options affects -the performance of your production code. -We're particularly interested in code that runs faster -when these options are @emph{disabled}, and in -non-Fortran code that benefits when they are -@emph{enabled} via the above @command{gcc} command-line options. +loop optimization is sufficiently advanced to perform all those +transformations without help from these options. @end table @xref{Optimize Options,,Options That Control Optimization, |