From: Jason Merrill <jason@redhat.com>
To: gcc-patches List <gcc-patches@gcc.gnu.org>
Subject: C++ PATCH for c++/83942, wrong -Wunused-but-set-var warning with static_cast
Date: Mon, 29 Jan 2018 18:13:00 -0000 [thread overview]
Message-ID: <CADzB+2kTe05D2Yd0MaMEhtcGMRREzkWmr3fzdO19CeDmSc2vnA@mail.gmail.com> (raw)
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Another caller of constant_value_1 that needs to handle calling
mark_rvalue_use now that cv1 doesn't.
Tested x86_64-pc-linux-gnu, applying to trunk.
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commit a8bc011a19fdb684c60cf4727d6a93ad2886d7ea
Author: Jason Merrill <jason@redhat.com>
Date: Mon Jan 29 09:16:05 2018 -0500
PR c++/83942 - wrong unused warning with static_cast.
* cvt.c (ocp_convert): Call mark_rvalue_use.
diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c
index 7ed2aad6136..3ab3e2e2b40 100644
--- a/gcc/cp/cvt.c
+++ b/gcc/cp/cvt.c
@@ -691,7 +691,10 @@ ocp_convert (tree type, tree expr, int convtype, int flags,
/* FIXME remove when moving to c_fully_fold model. */
if (!CLASS_TYPE_P (type))
- e = scalar_constant_value (e);
+ {
+ e = mark_rvalue_use (e);
+ e = scalar_constant_value (e);
+ }
if (error_operand_p (e))
return error_mark_node;
diff --git a/gcc/testsuite/g++.dg/warn/Wunused-var30.C b/gcc/testsuite/g++.dg/warn/Wunused-var30.C
new file mode 100644
index 00000000000..f3f7f1ae5bb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wunused-var30.C
@@ -0,0 +1,9 @@
+// PR c++/83942
+// { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wall" }
+
+enum class E { E1 };
+int main() {
+ E const e = E::E1;
+ return static_cast<int>(e);
+}
reply other threads:[~2018-01-29 15:46 UTC|newest]
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