[PR68432 10/22] Use code,alternative attributes for avr

[Richard Sandiford]

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

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

diff --git a/gcc/config/avr/avr.md b/gcc/config/avr/avr.md
index 1b39ddb..eb200ce 100644
--- a/gcc/config/avr/avr.md
+++ b/gcc/config/avr/avr.md
@@ -173,7 +173,8 @@
 (define_attr "isa"
   "mov,movw, rjmp,jmp, ijmp,eijmp, lpm,lpmx, elpm,elpmx, no_xmega,xmega, 
no_tiny,tiny,
    standard"
-  (const_string "standard"))
+  (const_string "standard")
+  "code,alternative")
 
 (define_attr "enabled" ""
   (cond [(eq_attr "isa" "standard")
@@ -235,7 +236,8 @@
               (match_test "!AVR_TINY"))
          (const_int 1)
 
-         ] (const_int 0)))
+         ] (const_int 0))
+  "code,alternative")
 
 
 ;; Define mode iterators