http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50012
--- Comment #2 from Mikael Pettersson <mikpe at it dot uu.se> 2011-08-14
12:25:12 UTC ---
The warning is lost due to this fragment of r148952 (with the rest of r148952
disabled):
--- gcc/cp/typeck.c (revision 148951)
+++ gcc/cp/typeck.c (revision 148952)
@@ -4018,6 +4018,8 @@ cp_build_binary_op (location_t location,
if ((short_compare || code == MIN_EXPR || code == MAX_EXPR)
&& warn_sign_compare
+ && !TREE_NO_WARNING (orig_op0)
+ && !TREE_NO_WARNING (orig_op1)
/* Do not warn until the template is instantiated; we cannot
bound the ranges of the arguments until that point. */
&& !processing_template_decl
In this test case (the foo() function) the LHS is a parenthesized expression,
and cp/semantics.c:finish_parenthesized_expr() contains the following gem:
tree
finish_parenthesized_expr (tree expr)
{
if (EXPR_P (expr))
/* This inhibits warnings in c_common_truthvalue_conversion. */
TREE_NO_WARNING (expr) = 1;
Disabling either the setting of TREE_NO_WARNING in finish_parenthesized_expr or
the && !TREE_NO_WARNING check in cp_build_binary_op restores the warning for
this test case. Alas I'm sure something else will break in that case ...
