c-tree.texi (VAR_DECL): Describe representation of GCC's extension for placing…

c-tree.texi (VAR_DECL): Describe representation of GCC's extension for placing variables in particular...

	* c-tree.texi (VAR_DECL): Describe representation of GCC's
	extension for placing variables in particular registers.

From-SVN: r37322

gcc/ChangeLog

 2000-11-08  Mark Mitchell  <mark@codesourcery.com>
 
+	* c-tree.texi (VAR_DECL): Describe representation of GCC's
+	extension for placing variables in particular registers.
+
 	* c-tree.texi (FUNCTION_TYPE): Clarify TYPE_ARG_TYPES for
 	unprototyped C functions with no parameters.
 

gcc/c-tree.texi

@@ -991,6 +991,13 @@ performed.  If the @code{DECL_INITIAL} is the @code{error_mark_node},
 there is an initializer, but it is given by an explicit statement later
 in the code; no bitwise copy is required.
 
+GCC provides an extension that allows either automatic variables, or
+global variables, to be placed in particular registers.  This extension
+is being used for a particular @code{VAR_DECL} if @code{DECL_REGISTER}
+holds for the @code{VAR_DECL}, and if @code{DECL_ASSEMBLER_NAME} is not
+equal to @code{DECL_NAME}.  In that case, @code{DECL_ASSEMBLER_NAME} is
+the name of the register into which the variable will be placed.
+
 @item PARM_DECL
 Used to represent a parameter to a function.  Treat these nodes
 similarly to @code{VAR_DECL} nodes.  These nodes only appear in the