flow.c (find_auto_inc): Clear UNCHANGING bit of register that is changed.

        * flow.c (find_auto_inc): Clear UNCHANGING bit of register that is
        changed.

From-SVN: r20974

gcc/ChangeLog

@@ -13,6 +13,9 @@ Mon Jul  6 22:50:48 1998  Jason Merrill  <jason@yorick.cygnus.com>
 
 Mon Jul  6 22:47:55 1998  J"orn Rennecke <amylaar@cygnus.co.uk>
 
+	* flow.c (find_auto_inc): Clear UNCHANGING bit of register that is
+	changed.
+
 	* reload1.c (reload_reg_free_before_p): RELOAD_FOR_OPADDR_ADDR
 	precedes RELOAD_FOR_OUTADDR_ADDRESS.
 

gcc/flow.c

@@ -2386,6 +2386,10 @@ find_auto_inc (needed, x, insn)
 		 Then fall into the usual case.  */
 	      rtx insns, temp;
 
+	      /* Since q is now changed, clear its UNCHANGING bit.  Otherwise,
+		 we would confuse alias.c when this pseudo ends up in a stack
+		 slot.  */
+	      RTX_UNCHANGING_P (q) = 0;
 	      start_sequence ();
 	      emit_move_insn (q, addr);
 	      insns = get_insns ();