[power7-meissner] Update constraints documentation

[Michael Meissner]

2009-03-02  Michael Meissner  <meissner@linux.vnet.ibm.com>

	* doc/md.texi (Machine Constraints): Update rs6000 constraints.

Index: gcc/doc/md.texi
===================================================================
--- gcc/doc/md.texi	(revision 144557)
+++ gcc/doc/md.texi	(working copy)
@@ -1907,8 +1907,17 @@ Floating point register
 @item v
 Altivec vector register
 
-@item w
-VSX vector register (floating point and altivec)
+@item wd
+VSX vector register to hold vector double data
+
+@item wf
+VSX vector register to hold vector float data
+
+@item ws
+VSX vector register to hold scalar float data
+
+@item wa
+Any VSX register
 
 @item h
 @samp{MQ}, @samp{CTR}, or @samp{LINK} register

-- 
Michael Meissner, IBM
4 Technology Place Drive, MS 2203A, Westford, MA, 01886, USA
meissner@linux.vnet.ibm.com