Patchwork [09/10] -fuse-caller-save - Add documentation

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Submitter Tom de Vries
Date March 30, 2013, 5:12 p.m.
Message ID <20130330171205.85752421213@build1-lucid-cs>
Download mbox | patch
Permalink /patch/232541/
State New
Headers show

Comments

Tom de Vries - March 30, 2013, 5:12 p.m.
Vladimir,

This patch adds the documentation of -fuse-caller-save.

Thanks,
  -Tom

2013-03-30  Radovan Obradovic  <robradovic@mips.com>
            Tom de Vries  <tom@codesourcery.com>

	* doc/invoke.texi (@item Optimization Options): Add -fuse-caller-save to
	gccoptlist.
	(@item -fuse-caller-save): New item.

Patch

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 475dcf0..efb8a1a 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -421,8 +421,8 @@  Objective-C and Objective-C++ Dialects}.
 -ftree-ter -ftree-vect-loop-version -ftree-vectorize -ftree-vrp @gol
 -funit-at-a-time -funroll-all-loops -funroll-loops @gol
 -funsafe-loop-optimizations -funsafe-math-optimizations -funswitch-loops @gol
--fvariable-expansion-in-unroller -fvect-cost-model -fvpt -fweb @gol
--fwhole-program -fwpa -fuse-ld=@var{linker} -fuse-linker-plugin @gol
+-fuse-caller-save -fvariable-expansion-in-unroller -fvect-cost-model -fvpt @gol
+-fweb -fwhole-program -fwpa -fuse-ld=@var{linker} -fuse-linker-plugin @gol
 --param @var{name}=@var{value}
 -O  -O0  -O1  -O2  -O3  -Os -Ofast -Og}
 
@@ -7382,6 +7382,14 @@  and then tries to find ways to combine them.
 
 Enabled by default at @option{-O1} and higher.
 
+@item -fuse-caller-save
+Use caller save registers for allocation if those registers are not used by
+any called function.  In that case it is not necessary to save and restore
+them around calls.  This is only possible if called functions are part of
+same compilation unit as current function and they are compiled before it.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
 @item -fconserve-stack
 @opindex fconserve-stack
 Attempt to minimize stack usage.  The compiler attempts to use less