2002-08-05  Jakub Jelinek  <jakub@redhat.com>

	* fold-const.c (associate_trees): Only optimize NEGATE_EXPR in one
	of the operands into MINUS_EXPR if code is PLUS_EXPR.

	* gcc.c-torture/execute/20020805-1.c: New test.

--- gcc/testsuite/gcc.c-torture/execute/20020805-1.c.jj	2002-08-05 18:27:42.000000000 +0200
+++ gcc/testsuite/gcc.c-torture/execute/20020805-1.c	2002-08-05 18:26:42.000000000 +0200
@@ -0,0 +1,21 @@
+/* This testcase was miscompiled on IA-32, because fold-const
+   assumed associate_trees is always done on PLUS_EXPR.  */
+
+extern void abort (void);
+extern void exit (int);
+
+void check (unsigned int m)
+{
+  if (m != (unsigned int) -1)
+    abort ();
+}
+
+unsigned int n = 1;
+
+int main (void)
+{
+  unsigned int m;
+  m = (1 | (2 - n)) | (-n);
+  check (m);
+  exit (0);
+}
--- gcc/fold-const.c.jj	2002-08-05 18:16:25.000000000 +0200
+++ gcc/fold-const.c	2002-08-05 18:16:25.000000000 +0200
@@ -1500,14 +1500,16 @@ associate_trees (t1, t2, code, type)
   if (TREE_CODE (t1) == code || TREE_CODE (t2) == code
       || TREE_CODE (t1) == MINUS_EXPR || TREE_CODE (t2) == MINUS_EXPR)
     {
-      if (TREE_CODE (t1) == NEGATE_EXPR)
-	return build (MINUS_EXPR, type, convert (type, t2),
-		      convert (type, TREE_OPERAND (t1, 0)));
-      else if (TREE_CODE (t2) == NEGATE_EXPR)
-	return build (MINUS_EXPR, type, convert (type, t1),
-		      convert (type, TREE_OPERAND (t2, 0)));
-      else
-	return build (code, type, convert (type, t1), convert (type, t2));
+      if (code == PLUS_EXPR)
+	{
+	  if (TREE_CODE (t1) == NEGATE_EXPR)
+	    return build (MINUS_EXPR, type, convert (type, t2),
+			  convert (type, TREE_OPERAND (t1, 0)));
+	  else if (TREE_CODE (t2) == NEGATE_EXPR)
+	    return build (MINUS_EXPR, type, convert (type, t1),
+			  convert (type, TREE_OPERAND (t2, 0)));
+	}
+      return build (code, type, convert (type, t1), convert (type, t2));
     }
 
   return fold (build (code, type, convert (type, t1), convert (type, t2)));