[C++ PATCH 1/4] Handle location wrappers better in warn_logical_operator.

[Jason Merrill]

When we introduced location wrappers, we added fold_for_warn to warnings
that are interested in a constant value, or wrapper-stripping to warnings
that are interested in literal constants.  This particular warning is
looking for a literal constant, but was wrongly changed to use
fold_for_warn; this patch makes it strip instead.

Tested x86_64-pc-linux-gnu, applying to trunk.

	* c-warn.c (warn_logical_operator): Strip location wrappers.  Don't
	fold_for_warn in "|| mask" warning.
---
 gcc/c-family/c-warn.c  | 40 ++++++++++++++++++++--------------------
 gcc/c-family/ChangeLog |  5 +++++
 2 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/gcc/c-family/c-warn.c b/gcc/c-family/c-warn.c
index d671b77a2b0..bee5449bcb1 100644
--- a/gcc/c-family/c-warn.c
+++ b/gcc/c-family/c-warn.c
@@ -208,32 +208,32 @@ warn_logical_operator (location_t location, enum tree_code code, tree type,
      programmer. That is, an expression such as op && MASK
      where op should not be any boolean expression, nor a
      constant, and mask seems to be a non-boolean integer constant.  */
+  STRIP_ANY_LOCATION_WRAPPER (op_right);
   if (TREE_CODE (op_right) == CONST_DECL)
     /* An enumerator counts as a constant.  */
     op_right = DECL_INITIAL (op_right);
+  tree stripped_op_left = tree_strip_any_location_wrapper (op_left);
   if (!truth_value_p (code_left)
       && INTEGRAL_TYPE_P (TREE_TYPE (op_left))
-      && !CONSTANT_CLASS_P (op_left)
-      && !TREE_NO_WARNING (op_left))
+      && !CONSTANT_CLASS_P (stripped_op_left)
+      && TREE_CODE (stripped_op_left) != CONST_DECL
+      && !TREE_NO_WARNING (op_left)
+      && TREE_CODE (op_right) == INTEGER_CST
+      && !integer_zerop (op_right)
+      && !integer_onep (op_right))
     {
-      tree folded_op_right = fold_for_warn (op_right);
-      if (TREE_CODE (folded_op_right) == INTEGER_CST
-	  && !integer_zerop (folded_op_right)
-	  && !integer_onep (folded_op_right))
-	{
-	  bool warned;
-	  if (or_op)
-	    warned
-	      = warning_at (location, OPT_Wlogical_op,
-			    "logical %<or%> applied to non-boolean constant");
-	  else
-	    warned
-	      = warning_at (location, OPT_Wlogical_op,
-			    "logical %<and%> applied to non-boolean constant");
-	  if (warned)
-	    TREE_NO_WARNING (op_left) = true;
-	  return;
-	}
+      bool warned;
+      if (or_op)
+	warned
+	  = warning_at (location, OPT_Wlogical_op,
+			"logical %<or%> applied to non-boolean constant");
+      else
+	warned
+	  = warning_at (location, OPT_Wlogical_op,
+			"logical %<and%> applied to non-boolean constant");
+      if (warned)
+	TREE_NO_WARNING (op_left) = true;
+      return;
     }
 
   /* We do not warn for constants because they are typical of macro
diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 2b700c2c4bd..93bdf3e0798 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,8 @@
+2019-09-15  Jason Merrill  <jason@redhat.com>
+
+	* c-warn.c (warn_logical_operator): Strip location wrappers.  Don't
+	fold_for_warn in "|| mask" warning.
+
 2019-09-10  Martin Liska  <mliska@suse.cz>
 
 	* c.opt: Use newly added WarnRemoved.

base-commit: ce026385ee57427978053620a038bffaac90819e
-- 
2.21.0