If purge_addressof_1 fails to remove addressofs in notes, remove the notes

instead.

From-SVN: r30414

gcc/ChangeLog

+Fri Nov  5 10:07:25 1999  Nick Clifton  <nickc@cygnus.com>
+
+	* function.c (is_addressof): New function.  Returns true if
+	the given piece of RTL is an ADDRESSOF.
+	(purge_addressof_1): Make boolean.  Return false if the
+	ADDRESSOFs could not be purged.
+	(purge_addressof): If ADDRESSOFs could not be purged from the
+	notes attached to an insn, remove the offending note(s),
+	unless they are attached to a libcall.
+
 1999-11-05  Andreas Jaeger  <aj@suse.de>
 
 	* genoutput.c (null_operand =): Initialize all fields.

gcc/function.c

@@ -268,8 +268,9 @@ static int all_blocks		PROTO((tree, tree *));
 static int *record_insns	PROTO((rtx)) ATTRIBUTE_UNUSED;
 static int contains		PROTO((rtx, int *));
 static void put_addressof_into_stack PROTO((rtx, struct hash_table *));
-static void purge_addressof_1	PROTO((rtx *, rtx, int, int, 
+static boolean purge_addressof_1 PROTO((rtx *, rtx, int, int, 
 				       struct hash_table *));
+static int is_addressof		PROTO ((rtx *, void *));
 static struct hash_entry *insns_for_mem_newfunc PROTO((struct hash_entry *,
 						       struct hash_table *,
 						       hash_table_key));
@@ -2765,9 +2766,10 @@ static rtx purge_addressof_replacements;
 
 /* Helper function for purge_addressof.  See if the rtx expression at *LOC
    in INSN needs to be changed.  If FORCE, always put any ADDRESSOFs into
-   the stack.  */
+   the stack.  If the function returns FALSE then the replacement could not
+   be made.  */
 
-static void
+static boolean
 purge_addressof_1 (loc, insn, force, store, ht)
      rtx *loc;
      rtx insn;
@@ -2778,13 +2780,14 @@ purge_addressof_1 (loc, insn, force, store, ht)
   RTX_CODE code;
   int i, j;
   const char *fmt;
+  boolean result = true;
 
   /* Re-start here to avoid recursion in common cases.  */
  restart:
 
   x = *loc;
   if (x == 0)
-    return;
+    return true;
 
   code = GET_CODE (x);
 
@@ -2793,9 +2796,9 @@ purge_addressof_1 (loc, insn, force, store, ht)
      memory.  */
   if (code == SET)
     {
-      purge_addressof_1 (&SET_DEST (x), insn, force, 1, ht);
-      purge_addressof_1 (&SET_SRC (x), insn, force, 0, ht);
-      return;
+      result = purge_addressof_1 (&SET_DEST (x), insn, force, 1, ht);
+      result &= purge_addressof_1 (&SET_SRC (x), insn, force, 0, ht);
+      return result;
     }
 
   else if (code == ADDRESSOF && GET_CODE (XEXP (x, 0)) == MEM)
@@ -2807,7 +2810,7 @@ purge_addressof_1 (loc, insn, force, store, ht)
 
       if (validate_change (insn, loc, sub, 0)
 	  || validate_replace_rtx (x, sub, insn))
-	return;
+	return true;
   
       start_sequence ();
       sub = force_operand (sub, NULL_RTX);
@@ -2818,7 +2821,7 @@ purge_addressof_1 (loc, insn, force, store, ht)
       insns = gen_sequence ();
       end_sequence ();
       emit_insn_before (insns, insn);
-      return;
+      return true;
     }
 
   else if (code == MEM && GET_CODE (XEXP (x, 0)) == ADDRESSOF && ! force)
@@ -2853,7 +2856,7 @@ purge_addressof_1 (loc, insn, force, store, ht)
 		if (rtx_equal_p (x, XEXP (tem, 0)))
 		  {
 		    *loc = XEXP (XEXP (tem, 1), 0);
-		    return;
+		    return true;
 		  }
 
 	      /* See comment for purge_addressof_replacements. */
@@ -2896,8 +2899,14 @@ purge_addressof_1 (loc, insn, force, store, ht)
 		    return;
 		  }
 
-	      /* There should always be such a replacement.  */
-	      abort ();
+	      /* Sometimes we may not be able to find the replacement.  For
+		 example when the original insn was a MEM in a wider mode,
+		 and the note is part of a sign extension of a narrowed
+		 version of that MEM.  Gcc testcase compile/990829-1.c can
+		 generate an example of this siutation.  Rather than complain
+		 we return false, which will prompt our caller to remove the
+		 offending note.  */
+	      return false;
 	    }
 
 	  size_x = GET_MODE_BITSIZE (GET_MODE (x));
@@ -2989,7 +2998,7 @@ purge_addressof_1 (loc, insn, force, store, ht)
 				      purge_bitfield_addressof_replacements));
 
 	      /* We replaced with a reg -- all done.  */
-	      return;
+	      return true;
 	    }
 	}
 
@@ -3007,13 +3016,13 @@ purge_addressof_1 (loc, insn, force, store, ht)
 		if (rtx_equal_p (XEXP (x, 0), XEXP (tem, 0)))
 		  {
 		    XEXP (XEXP (tem, 1), 0) = sub;
-		    return;
+		    return true;
 		  }
 	      purge_addressof_replacements
 		= gen_rtx (EXPR_LIST, VOIDmode, XEXP (x, 0),
 			   gen_rtx_EXPR_LIST (VOIDmode, sub,
 					      purge_addressof_replacements));
-	      return;
+	      return true;
 	    }
 	  goto restart;
 	}
@@ -3028,9 +3037,9 @@ purge_addressof_1 (loc, insn, force, store, ht)
     }
   else if (code == SET)
     {
-      purge_addressof_1 (&SET_DEST (x), insn, force, 1, ht);
-      purge_addressof_1 (&SET_SRC (x), insn, force, 0, ht);
-      return;
+      result = purge_addressof_1 (&SET_DEST (x), insn, force, 1, ht);
+      result &= purge_addressof_1 (&SET_SRC (x), insn, force, 0, ht);
+      return result;
     }
 
   /* Scan all subexpressions. */
@@ -3038,11 +3047,13 @@ purge_addressof_1 (loc, insn, force, store, ht)
   for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++)
     {
       if (*fmt == 'e')
-	purge_addressof_1 (&XEXP (x, i), insn, force, 0, ht);
+	result &= purge_addressof_1 (&XEXP (x, i), insn, force, 0, ht);
       else if (*fmt == 'E')
 	for (j = 0; j < XVECLEN (x, i); j++)
-	  purge_addressof_1 (&XVECEXP (x, i, j), insn, force, 0, ht);
+	  result &= purge_addressof_1 (&XVECEXP (x, i, j), insn, force, 0, ht);
     }
+
+  return result;
 }
 
 /* Return a new hash table entry in HT.  */
@@ -3162,6 +3173,16 @@ compute_insns_for_mem (insns, last_insn, ht)
 	}
 }
 
+/* Helper function for purge_addressof called through for_each_rtx.
+   Returns true iff the rtl is an ADDRESSOF.  */
+static int
+is_addressof (rtl, data)
+     rtx * rtl;
+     void * data ATTRIBUTE_UNUSED;
+{
+  return GET_CODE (* rtl) == ADDRESSOF;
+}
+
 /* Eliminate all occurrences of ADDRESSOF from INSNS.  Elide any remaining
    (MEM (ADDRESSOF)) patterns, and force any needed registers into the
    stack.  */
@@ -3190,9 +3211,30 @@ purge_addressof (insns)
     if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN
 	|| GET_CODE (insn) == CALL_INSN)
       {
-	purge_addressof_1 (&PATTERN (insn), insn,
-			   asm_noperands (PATTERN (insn)) > 0, 0, &ht);
-	purge_addressof_1 (&REG_NOTES (insn), NULL_RTX, 0, 0, &ht);
+	if (! purge_addressof_1 (&PATTERN (insn), insn,
+				 asm_noperands (PATTERN (insn)) > 0, 0, &ht))
+	  /* If we could not replace the ADDRESSOFs in the insn,
+	     something is wrong.  */
+	  abort ();
+	
+	if (! purge_addressof_1 (&REG_NOTES (insn), NULL_RTX, 0, 0, &ht))
+	  {
+	    /* If we could not replace the ADDRESSOFs in the insn's notes,
+	       we can just remove the offending notes instead.  */
+	    rtx note;
+
+	    for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
+	      {
+		/* If we find a REG_RETVAL note then the insn is a libcall.
+		   Such insns must have REG_EQUAL notes as well, in order
+		   for later passes of the compiler to work.  So it is not
+		   safe to delete the notes here, and instead we abort.  */
+		if (REG_NOTE_KIND (note) == REG_RETVAL)
+		  abort ();
+		if (for_each_rtx (& note, is_addressof, NULL))
+		  remove_note (insn, note);
+	      }
+	  }
       }
 
   /* Clean up.  */