* invoke.texi: Document __FAST_MATH__.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@40249 138bc75d-0d04-0410-961f-82ee72b054a4

gcc/ChangeLog

+2001-03-05  Brad Lucier  <lucier@math.purdue.edu>
+
+	* invoke.texi: Document __FAST_MATH__.
+
 2001-03-05  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	* crtstuff.c: Restore include of auto-host.h.

gcc/invoke.texi

@@ -2940,6 +2940,8 @@ example, it allows the compiler to assume arguments to the @code{sqrt}
 function are non-negative numbers and that no floating-point values
 are NaNs.
 
+This option causes the preprocessor macro __FAST_MATH__ to be defined.
+
 This option should never be turned on by any @samp{-O} option since
 it can result in incorrect output for programs which depend on
 an exact implementation of IEEE or ISO rules/specifications for