Clean up pass over sparc -m{cpu,tune} docs.

From-SVN: r16245

gcc/invoke.texi

@@ -3086,17 +3086,36 @@ These options are deprecated and will be deleted in GNU CC 2.9.
 They have been replaced with @samp{-mcpu=xxx}.
 
 @item -mcpu=@var{cpu_type}
-Set architecture type and instruction scheduling parameters for machine
-type @var{cpu_type}.  Supported values for @var{cpu_type} are
-@samp{v7}, @samp{cypress}, @samp{v8}, @samp{supersparc},
-@samp{sparclite}, @samp{f930}, @samp{f934}, @samp{sparclet}, @samp{tsc701},
-@samp{v8plus}, @samp{v9}, and @samp{ultrasparc}.
+Set the instruction set, register set, and instruction scheduling parameters
+for machine type @var{cpu_type}.  Supported values for @var{cpu_type} are
+@samp{v7}, @samp{cypress}, @samp{v8}, @samp{supersparc}, @samp{sparclite},
+@samp{f930}, @samp{f934}, @samp{sparclet}, @samp{tsc701}, @samp{v9}, and
+@samp{ultrasparc}.
+
+Default instruction scheduling parameters are used for values that select
+an architecture and not an implementation.  These are @samp{v7}, @samp{v8},
+@samp{sparclite}, @samp{sparclet}, @samp{v9}.
+
+Here is a list of each supported architecture and their supported
+implementations.
+
+@smallexample
+    v7:             cypress
+    v8:             supersparc
+    sparclite:      f930, f934
+    sparclet:       tsc701
+    v9:             ultrasparc
+@end smallexample
 
 @item -mtune=@var{cpu_type}
 Set the instruction scheduling parameters for machine type
-@var{cpu_type}, but do not set the architecture type as the option
-@samp{-mcpu=}@var{cpu_type} would.  The same values for
-@samp{-mcpu=}@var{cpu_type} are used for @samp{-mtune=}@var{cpu_type}.
+@var{cpu_type}, but do not set the instruction set or register set that the
+option @samp{-mcpu=}@var{cpu_type} would.
+
+The same values for @samp{-mcpu=}@var{cpu_type} are used for
+@samp{-mtune=}@var{cpu_type}, though the only useful values are those that
+select a particular cpu implementation: @samp{cypress}, @samp{supersparc},
+@samp{f930}, @samp{f934}, @samp{tsc701}, @samp{ultrasparc}.
 
 @item -malign-loops=@var{num}
 Align loops to a 2 raised to a @var{num} byte boundary.  If