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[texi, LTO]: Mention that -flto and -fwhole-program can be used simultaneously
- From: Tobias Burnus <burnus at net-b dot de>
- To: gcc-patches at gcc dot gnu dot org
- Date: Mon, 5 Oct 2009 18:26:13 +0200
- Subject: [texi, LTO]: Mention that -flto and -fwhole-program can be used simultaneously
Hi all,
I had the impression that it is not obvious that -fwhole-program can be
applied simultaneously -- and that one may think that -flto already
does the -fwhole-program optimizations as it sees the whole program
(which is not the case).
I therefore propose to add a note to the manual as proposed below.
OK for the trunk? Or do you have a better suggestion for the wording?
Tobias
2009-10-05 Tobias Burnus <burnus@net-b.de>
* doc/invoke.texi (-flto,-fwhole-program): Make clear that the
-flto and -fwhole-program flags can be combined.
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 152454)
+++ gcc/doc/invoke.texi (working copy)
@@ -7105,9 +7105,9 @@
and in effect are optimized more aggressively by interprocedural optimizers.
While this option is equivalent to proper use of the @code{static} keyword for
programs consisting of a single file, in combination with option
-@option{--combine} this flag can be used to compile many smaller scale C
-programs since the functions and variables become local for the whole combined
-compilation unit, not for the single source file itself.
+@option{-combine} or @option{-flto} this flag can be used to compile many
+smaller scale programs since the functions and variables become local for the
+whole combined compilation unit, not for the single source file itself.
This option implies @option{-fwhole-file} for Fortran programs.
@@ -7223,7 +7223,8 @@
should use the same link command used when mixing languages in a
regular (non-LTO) compilation. This means that if your build process
was mixing languages before, all you need to add is @option{-flto} to
-all the compile and link commands.
+all the compile and link commands. Note that @option{-flto} can be
+combined with the @option{-fwhole-program} flag.
If object files containing GIMPLE bytecode are stored in a library
archive, say @file{libfoo.a}, it is possible to extract and use them