Improve movstrXX documentation.

From-SVN: r17587

diff --git a/gcc/md.texi b/gcc/md.texi
index 7deeb3e077b8ca2883fdbdf873283c2edf505044..119ceda3c9b7a4ae301de486c4c45ae7df0ab546 100644 (file)
--- a/gcc/md.texi
+++ b/gcc/md.texi
@@ -1956,6 +1956,12 @@ destination, in the form of a @code{const_int} rtx.  Thus, if the
 compiler knows that both source and destination are word-aligned,
 it may provide the value 4 for this operand.
 
 compiler knows that both source and destination are word-aligned,
 it may provide the value 4 for this operand.
 

+Descriptions of multiple @code{movstr@var{m}} patterns can only be
+beneficial if the patterns for smaller modes have less restrictions
+on their first, second and fourth operands.  Note that the mode @var{m}
+in @code{movstr@var{m}} does not impose any restriction on the mode of
+individually moved data units in the block.
+

 These patterns need not give special consideration to the possibility
 that the source and destination strings might overlap.
 
 These patterns need not give special consideration to the possibility
 that the source and destination strings might overlap.
 


@@ -1970,6 +1976,8 @@ of a @code{const_int} rtx.  Thus, if the compiler knows that the
 destination is word-aligned, it may provide the value 4 for this
 operand.
 
 destination is word-aligned, it may provide the value 4 for this
 operand.
 

+The use for multiple @code{clrstr@var{m}} is as for @code{movstr@var{m}}.
+

 @cindex @code{cmpstr@var{m}} instruction pattern
 @item @samp{cmpstr@var{m}}
 Block compare instruction, with five operands.  Operand 0 is the output;
 @cindex @code{cmpstr@var{m}} instruction pattern
 @item @samp{cmpstr@var{m}}
 Block compare instruction, with five operands.  Operand 0 is the output;