Hi!
convert_arg_to_ellipsis used to call decay_conversion for all types
(which calls mark_rvalue_use), but it doesn't anymore in GCC 10,
and while for INTEGRAL_OR_ENUMERATION_TYPE_P args it calls
cp_perform_integral_promotions which does that too and for aggregate
args keeps calling decay_conversion, for floating point or decltype(nullptr)
args there is nothing that would shut up -Wunused-but-set-* warning
(and I guess equally also handle lambda captures).
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2019-12-19 Jakub Jelinek <ja...@redhat.com>
PR c++/92666
* call.c (convert_arg_to_ellipsis): For floating point or
decltype(nullptr) arguments call mark_rvalue_use.
* g++.dg/warn/Wunused-var-36.C: New test.
--- gcc/cp/call.c.jj 2019-12-17 10:19:51.013282361 +0100
+++ gcc/cp/call.c 2019-12-18 18:23:01.441357443 +0100
@@ -7819,10 +7819,12 @@ convert_arg_to_ellipsis (tree arg, tsubs
"implicit conversion from %qH to %qI when passing "
"argument to function",
arg_type, double_type_node);
+ arg = mark_rvalue_use (arg);
arg = convert_to_real_nofold (double_type_node, arg);
}
else if (NULLPTR_TYPE_P (arg_type))
{
+ arg = mark_rvalue_use (arg);
if (TREE_SIDE_EFFECTS (arg))
arg = cp_build_compound_expr (arg, null_pointer_node, complain);
else
--- gcc/testsuite/g++.dg/warn/Wunused-var-36.C.jj 2019-12-18
18:05:50.804946325 +0100
+++ gcc/testsuite/g++.dg/warn/Wunused-var-36.C 2019-12-18 18:40:19.130654606
+0100
@@ -0,0 +1,25 @@
+// PR c++/92666
+// { dg-do compile }
+// { dg-options "-Wunused-but-set-variable" }
+
+int bar (int, ...);
+#if __cplusplus >= 201103L
+enum class E : int { F = 0, G = 1 };
+#endif
+struct S { int s; };
+
+void
+foo ()
+{
+ float r = 1.0f; // { dg-bogus "set but not used" }
+ int i = 2; // { dg-bogus "set but not used" }
+#if __cplusplus >= 201103L
+ decltype(nullptr) n = nullptr; // { dg-bogus "set but not used" }
+ E e = E::F; // { dg-bogus "set but not used" }
+#else
+ void *n = (void *) 0;
+ int e = 4;
+#endif
+ S s = { 3 }; // { dg-bogus "set but not used" }
+ bar (0, r, i, n, e, s);
+}
Jakub
