re PR tree-optimization/89536 (wrong code at -Os and above on x86_64-linux-gnu)

	PR tree-optimization/89536
	* tree-ssa-dom.c (edge_info::derive_equivalences) <BIT_NOT_EXPR>: Test
	only whether bit #0 of the value is 0 instead of the entire value.

From-SVN: r269289

gcc/ChangeLog

+2019-02-28  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR tree-optimization/89536
+	* tree-ssa-dom.c (edge_info::derive_equivalences) <BIT_NOT_EXPR>: Test
+	only whether bit #0 of the value is 0 instead of the entire value.
+
 2019-02-28  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/87068 - missing diagnostic with fallthrough statement.

gcc/testsuite/ChangeLog

+2019-02-28  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc.c-torture/execute/20190228-1.c: New test.
+
 2019-02-28  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/87068 - missing diagnostic with fallthrough statement.

gcc/testsuite/gcc.c-torture/execute/20190228-1.c

+/* PR tree-optimization/89536 */
+/* Testcase by Zhendong Su <su@cs.ucdavis.edu> */
+
+int a = 1;
+
+int main (void)
+{
+  a = ~(a && 1); 
+  if (a < -1)
+    a = ~a;
+  
+  if (!a)
+    __builtin_abort ();
+
+  return 0;
+}

gcc/tree-ssa-dom.c

@@ -348,7 +348,7 @@ edge_info::derive_equivalences (tree name, tree value, int recursion_limit)
 		&& TREE_CODE (rhs) == SSA_NAME
 		&& ssa_name_has_boolean_range (rhs))
 	      {
-		if (integer_zerop (value))
+		if ((TREE_INT_CST_LOW (value) & 1) == 0)
 		  res = build_one_cst (TREE_TYPE (rhs));
 		else
 		  res = build_zero_cst (TREE_TYPE (rhs));