md.texi (constraints): Mention that it is useless when the two alternatives are strictly identical.

	* doc/md.texi (constraints) <% modifier>: Mention that it is
	useless when the two alternatives are strictly identical.

From-SVN: r90598

gcc/ChangeLog

+2004-11-13  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	* doc/md.texi (constraints) <% modifier>: Mention that it is
+	useless when the two alternatives are strictly identical.
+
 2004-11-13  Richard Henderson  <rth@redhat.com>
 
 	* expmed.c (extract_split_bit_field): Temporarily disable call to

gcc/doc/md.texi

@@ -1550,7 +1550,9 @@ instruction is defined:
 @end smallexample
 @end ifset
 GCC can only handle one commutative pair in an asm; if you use more,
-the compiler may fail.
+the compiler may fail.  Note that you need not use the modifier if
+the two alternatives are strictly identical; this would only waste
+time in the reload pass.
 
 @cindex @samp{#} in constraint
 @item #