jump.c (rtx_unsafe_p): New function.

        * jump.c (rtx_unsafe_p): New function.
        (jump_optimize): Use it on if/then/else transformations and
        conditional move transformations.

From-SVN: r20200

gcc/ChangeLog

+Tue Jun  2 21:59:01 1998  Richard Henderson  <rth@cygnus.com>
+
+	* jump.c (rtx_unsafe_p): New function.
+	(jump_optimize): Use it on if/then/else transformations and
+	conditional move transformations.
+
 Tue Jun  2 22:50:10 1998  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>
 
 	* fold-const.c (fold, case EQ_EXPR): When folding VAR++ == CONST

gcc/jump.c

@@ -121,6 +121,7 @@ static void redirect_tablejump		PROTO((rtx, rtx));
 #ifndef HAVE_cc0
 static rtx find_insert_position         PROTO((rtx, rtx));
 #endif
+static int rtx_unsafe_p			PROTO((rtx));
 
 /* Delete no-op jumps and optimize jumps to jumps
    and jumps around jumps.
@@ -771,11 +772,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
 	      && GET_CODE (temp2) == INSN
 	      && (temp4 = single_set (temp2)) != 0
 	      && rtx_equal_p (SET_DEST (temp4), temp1)
-	      && (GET_CODE (SET_SRC (temp4)) == REG
-		  || GET_CODE (SET_SRC (temp4)) == SUBREG
-		  || (GET_CODE (SET_SRC (temp4)) == MEM
-		      && RTX_UNCHANGING_P (SET_SRC (temp4)))
-		  || CONSTANT_P (SET_SRC (temp4)))
+	      && ! rtx_unsafe_p (SET_SRC (temp4))
 	      && (REG_NOTES (temp2) == 0
 		  || ((REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUAL
 		       || REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUIV)
@@ -807,6 +804,16 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
 	      rtx q;
 #endif
 
+	      if (!(GET_CODE (SET_SRC (temp4)) == REG
+		    || GET_CODE (SET_SRC (temp4)) == SUBREG
+		    || (GET_CODE (SET_SRC (temp4)) == MEM
+			&& RTX_UNCHANGING_P (SET_SRC (temp4)))
+		    || CONSTANT_P (SET_SRC (temp4))))
+		{
+		  fprintf(stderr, "\nxyzzy 1\n");
+		  debug_rtx (temp4);
+		}
+
 	      /* Set P to the first jump insn that goes around "x = a;".  */
 	      for (p = temp; nuses && p; p = prev_nonnote_insn (p))
 		{
@@ -846,7 +853,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
 		  && ! reg_referenced_between_p (temp1, p, NEXT_INSN (temp3))
 		  && ! reg_set_between_p (temp1, p, temp3)
 		  && (GET_CODE (SET_SRC (temp4)) == CONST_INT
-		      || ! reg_set_between_p (SET_SRC (temp4), p, temp2)))
+		      || ! modified_between_p (SET_SRC (temp4), p, temp2)))
 		{
 		  emit_insn_after_with_line_notes (PATTERN (temp2), p, temp2);
 		  delete_insn (temp2);
@@ -1161,11 +1168,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
 	      && GET_CODE (temp1 = SET_DEST (PATTERN (temp))) == REG
 	      && (! SMALL_REGISTER_CLASSES
 		  || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
-	      && (GET_CODE (temp2 = SET_SRC (PATTERN (temp))) == REG
-		  || (GET_CODE (temp2) == MEM && RTX_UNCHANGING_P (temp2))
-		  || GET_CODE (temp2) == SUBREG
-		  /* ??? How about floating point constants?  */
-		  || CONSTANT_P (temp2))
+	      && ! rtx_unsafe_p (temp2 = SET_SRC (PATTERN (temp)))
 	      /* Allow either form, but prefer the former if both apply. 
 		 There is no point in using the old value of TEMP1 if
 		 it is a register, since cse will alias them.  It can
@@ -1203,6 +1206,16 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
 #endif
 	      )
 	    {
+	      if (! (GET_CODE (temp2) == REG
+		     || (GET_CODE (temp2) == MEM && RTX_UNCHANGING_P (temp2))
+		     || GET_CODE (temp2) == SUBREG
+		     /* ??? How about floating point constants?  */
+		     || CONSTANT_P (temp2)))
+		{
+		  fprintf(stderr, "\nxyzzy 2\n");
+		  debug_rtx (PATTERN (temp));
+		}
+
 #ifdef HAVE_conditional_move
 	      /* First try a conditional move.  */
 	      {
@@ -4783,4 +4796,73 @@ find_insert_position (insn, new)
 
   return reg_mentioned_p (SET_DEST (single_set (new)), prev) ? 0 : prev;
 }
+
+/* Return 1 if the value of X is unsafe to arbitrarily evaluate, i.e.
+   might fault on some arguments.  This is used in connection with
+   conditional move optimization.  */
+
+static int
+rtx_unsafe_p (x)
+     rtx x;
+{
+  register RTX_CODE code = GET_CODE (x);
+  register int i;
+  register char *fmt;
+
+  switch (code)
+    {
+    case MEM:
+      return ! RTX_UNCHANGING_P (x);
+
+    case QUEUED:
+      return 1;
+
+    case CONST_INT:
+    case CONST_DOUBLE:
+    case CONST_STRING:
+    case CONST:
+    case PC:
+    case LABEL_REF:
+    case SYMBOL_REF:
+    case ADDRESSOF:
+    case REG:
+      return 0;
+
+    case DIV:
+    case MOD:
+    case UDIV:
+    case UMOD:
+    case SQRT:
+      return 1;
+
+    default:
+      if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
+	  && !flag_fast_math
+	  && FLOAT_MODE_P (GET_MODE (x)))
+	return 1;
+
+      switch (GET_RTX_CLASS (code))
+	{
+	case '<':
+	case '1':
+	case '2':
+	case '3':
+	case 'c':
+	case 'b':
+	  break;
+
+	default:
+	  return 1;
+	}
+      break;
+    }
+
+  fmt = GET_RTX_FORMAT (code);
+  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+    if (fmt[i] == 'e')
+      if (rtx_unsafe_p (XEXP (x, i)))
+	return 1;
+
+  return 0;
+}
 #endif /* !HAVE_cc0 */