2007-03-31 Wolfgang Bangerth <bangerth@dealii.org>

            Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR 14737
	* doc/invoke.texi: (optimization options): Reword description
	of -ffast-math. Document its primary purpose.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@123382 138bc75d-0d04-0410-961f-82ee72b054a4

2 files changed, 20 insertions, 8 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4d6609fe3e8..729f70a97b0 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2007-03-31  Wolfgang Bangerth  <bangerth@dealii.org>
+            Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR 14737
+	* doc/invoke.texi: (optimization options): Reword description
+	of -ffast-math. Document its primary purpose.
+	
 2007-03-31  Richard Guenther  <rguenther@suse.de>
 
 	* omp-low.c (splay-tree.h): Include.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 38552b7fd7b..db0b743da1e 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -5909,10 +5909,11 @@ Sets @option{-fno-math-errno}, @option{-funsafe-math-optimizations}, @*
 
 This option causes the preprocessor macro @code{__FAST_MATH__} to be defined.
 
-This option should never be turned on by any @option{-O} option since
+This option is not turned on by any @option{-O} option since
 it can result in incorrect output for programs which depend on
 an exact implementation of IEEE or ISO rules/specifications for
-math functions.
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
 
 @item -fno-math-errno
 @opindex fno-math-errno
@@ -5921,10 +5922,11 @@ with a single instruction, e.g., sqrt.  A program that relies on
 IEEE exceptions for math error handling may want to use this flag
 for speed while maintaining IEEE arithmetic compatibility.
 
-This option should never be turned on by any @option{-O} option since
+This option is not turned on by any @option{-O} option since
 it can result in incorrect output for programs which depend on
 an exact implementation of IEEE or ISO rules/specifications for
-math functions.
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
 
 The default is @option{-fmath-errno}.
 
@@ -5940,10 +5942,11 @@ ANSI standards.  When used at link-time, it may include libraries
 or startup files that change the default FPU control word or other
 similar optimizations.
 
-This option should never be turned on by any @option{-O} option since
+This option is not turned on by any @option{-O} option since
 it can result in incorrect output for programs which depend on
 an exact implementation of IEEE or ISO rules/specifications for
-math functions.
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
 
 The default is @option{-fno-unsafe-math-optimizations}.
 
@@ -5952,9 +5955,11 @@ The default is @option{-fno-unsafe-math-optimizations}.
 Allow optimizations for floating-point arithmetic that assume
 that arguments and results are not NaNs or +-Infs.
 
-This option should never be turned on by any @option{-O} option since
+This option is not turned on by any @option{-O} option since
 it can result in incorrect output for programs which depend on
-an exact implementation of IEEE or ISO rules/specifications.
+an exact implementation of IEEE or ISO rules/specifications for
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
 
 The default is @option{-fno-finite-math-only}.