Only allow the "return" insn construct (which simply yields a "jmp r1" line)

if null_prologue(), i.e. if there is no stack frame to undo and no r1 to
restore.

Make the "epilogue" insn construct no longer depend on "return", but rather
on "(use (const_int 0))" as "prologue" and as generally done on other backends.
On the other hand, make it unconditionnal, instead of "! null_prologue()".

These changes make sure than a leaf procedure call does not end up "returning"
(i.e. jmp r1) upon return from the call, without restoring r1 and r30 (whenever
applicable) from the existing stack frame.

This makes a gcc3-compiled __main() (from libgcc2.c) no longer spin after
invoking the constructors, and gives the real payload (i.e. main() and whatever
follows from there) a chance to run.

1 files changed, 4 insertions, 4 deletions

diff --git a/gnu/usr.bin/gcc/gcc/config/m88k/m88k.md b/gnu/usr.bin/gcc/gcc/config/m88k/m88k.md
index a79cce0778c..7b2d6905984 100644
--- a/gnu/usr.bin/gcc/gcc/config/m88k/m88k.md
+++ b/gnu/usr.bin/gcc/gcc/config/m88k/m88k.md
@@ -4001,18 +4001,18 @@
 
 (define_insn "return"
   [(return)]
-  "reload_completed"
+  "null_prologue()"
   "jmp%. %#r1"
   [(set_attr "type" "jump")])
 
 (define_expand "prologue"
-  [(const_int 0)]
+  [(use (const_int 0))]
   ""
   "m88k_expand_prologue (); DONE;")
 
 (define_expand "epilogue"
-  [(return)]
-  "! null_prologue ()"
+  [(use (const_int 0))]
+  ""
   "m88k_expand_epilogue ();")
 
 (define_insn "blockage"