re PR sanitizer/70683 (-fcompare-debug bug with -fsanitize=address)

	PR sanitizer/70683
	* tree-core.h (enum operand_equal_flag): Add OEP_NO_HASH_CHECK.
	* fold-const.c (operand_equal_p): If flag_checking and
	OEP_NO_HASH_CHECK is not set in flag, recurse with OEP_NO_HASH_CHECK
	and if it returns non-zero, assert iterative_hash_expr on both
	args is the same.

From-SVN: r235507

gcc/ChangeLog

+2016-04-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR sanitizer/70683
+	* tree-core.h (enum operand_equal_flag): Add OEP_NO_HASH_CHECK.
+	* fold-const.c (operand_equal_p): If flag_checking and
+	OEP_NO_HASH_CHECK is not set in flag, recurse with OEP_NO_HASH_CHECK
+	and if it returns non-zero, assert iterative_hash_expr on both
+	args is the same.
+
 2016-04-27  Bernd Schmidt  <bschmidt@redhat.com>
 
 	* doc/invoke.texi (-frename-registers): Also enabled at -Os.

gcc/fold-const.c

@@ -2749,6 +2749,25 @@ combine_comparisons (location_t loc,
 int
 operand_equal_p (const_tree arg0, const_tree arg1, unsigned int flags)
 {
+  /* When checking, verify at the outermost operand_equal_p call that
+     if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
+     hash value.  */
+  if (flag_checking && !(flags & OEP_NO_HASH_CHECK))
+    {
+      if (operand_equal_p (arg0, arg1, flags | OEP_NO_HASH_CHECK))
+	{
+	  inchash::hash hstate0 (0), hstate1 (0);
+	  inchash::add_expr (arg0, hstate0, flags);
+	  inchash::add_expr (arg1, hstate1, flags);
+	  hashval_t h0 = hstate0.end ();
+	  hashval_t h1 = hstate1.end ();
+	  gcc_assert (h0 == h1);
+	  return 1;
+	}
+      else
+	return 0;
+    }
+
   /* If either is ERROR_MARK, they aren't equal.  */
   if (TREE_CODE (arg0) == ERROR_MARK || TREE_CODE (arg1) == ERROR_MARK
       || TREE_TYPE (arg0) == error_mark_node

gcc/tree-core.h

@@ -765,7 +765,9 @@ enum operand_equal_flag {
   OEP_ONLY_CONST = 1,
   OEP_PURE_SAME = 2,
   OEP_MATCH_SIDE_EFFECTS = 4,
-  OEP_ADDRESS_OF = 8
+  OEP_ADDRESS_OF = 8,
+  /* Internal within operand_equal_p:  */
+  OEP_NO_HASH_CHECK = 16
 };
 
 /* Enum and arrays used for tree allocation stats.