re PR tree-optimization/85822 (Maybe wrong code in VRP since r249150)

PR tree-optimization/85822

From-SVN: r260566

gcc/ChangeLog

+2018-05-23  Yury Gribov  <tetra2005@gmail.com>
+
+	PR tree-optimization/85822
+	* tree-vrp.c (is_masked_range_test): Fix handling of negative
+	constants.
+
 2018-05-23  Richard Biener  <rguenther@suse.de>
 
 	* tree-ssa-sccvn.c (vn_reference_lookup_3): Handle arbitrary

gcc/testsuite/ChangeLog

+2018-05-23  Yury Gribov  <tetra2005@gmail.com>
+
+	PR tree-optimization/85822
+	* c-c++-common/pr85822.c: New test.
+
 2018-05-23  Richard Biener  <rguenther@suse.de>
 
 	* gcc.dg/tree-ssa/ssa-fre-65.c: New testcase.

gcc/testsuite/c-c++-common/pr85822.c

+/* { dg-options "-O2" } */
+/* { dg-do run } */
+
+static const long long int TagTypeNumber = 0xffff000000000000ll;
+
+long long int x;
+
+void foo(void)
+{
+  x = TagTypeNumber + 1;
+}
+
+int main(int argc, char **argv)
+{
+  if (argc > 0)
+    foo ();
+
+  if ((x & TagTypeNumber) == TagTypeNumber)
+  {
+    unsigned y = (unsigned)x;
+    __builtin_printf ("v: %u\n", y);
+    if (y != 1)
+      __builtin_abort ();
+  }
+
+  return 0;
+}

gcc/tree-vrp.c

@@ -3844,10 +3844,10 @@ register_edge_assert_for_1 (tree op, enum tree_code code,
    Such comparison can yield assertions like
      X >= XX...X00...0
      X <= XX...X11...1
-   in case of COND_OP being NE_EXPR or
+   in case of COND_OP being EQ_EXPR or
      X < XX...X00...0
      X > XX...X11...1
-   in case of EQ_EXPR.  */
+   in case of NE_EXPR.  */
 
 static bool
 is_masked_range_test (tree name, tree valt, enum tree_code cond_code,
@@ -3867,6 +3867,10 @@ is_masked_range_test (tree name, tree valt, enum tree_code cond_code,
 
   wi::tree_to_wide_ref mask = wi::to_wide (maskt);
   wide_int inv_mask = ~mask;
+  /* Must have been removed by now so don't bother optimizing.  */
+  if (mask == 0 || inv_mask == 0)
+    return false;
+
   /* Assume VALT is INTEGER_CST.  */
   wi::tree_to_wide_ref val = wi::to_wide (valt);
 
@@ -3907,9 +3911,6 @@ is_masked_range_test (tree name, tree valt, enum tree_code cond_code,
   *low = wide_int_to_tree (type, val);
   *high = wide_int_to_tree (type, val | inv_mask);
 
-  if (wi::neg_p (val, TYPE_SIGN (type)))
-    std::swap (*low, *high);
-
   return true;
 }