[PR68432 15/22] Use code,alternative attributes for mn10300

[Richard Sandiford]

Tested as described in the covering note.  I plan to commit this as obvious
if the prerequisites are approved.

gcc/
        * config/mn10300/mn10300.md (isa): Turn into a code,alternative
        attribute.
        (enabled): Likewise.

diff --git a/gcc/config/mn10300/mn10300.md b/gcc/config/mn10300/mn10300.md
index 7cd5306..e1ae283 100644
--- a/gcc/config/mn10300/mn10300.md
+++ b/gcc/config/mn10300/mn10300.md
@@ -54,7 +54,8 @@
 
 ;; Used to control the "enabled" attribute on a per-instruction basis.
 (define_attr "isa" "base,am33,am33_2,am34"
-  (const_string "base"))
+  (const_string "base")
+  "code,alternative")
 
 (define_attr "enabled" ""
   (cond [(eq_attr "isa" "base")
@@ -73,6 +74,7 @@
          (const_int 1)
        ]
        (const_int 0))
+  "code,alternative"
 )
 
 (define_mode_iterator INT [QI HI SI])