From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 29 May 2018 17:07:57 +0000 (+0200)
Subject: re PR c++/85952 (Bogus -Wunused-but-set-variable warning with array structured binding)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=69ce0c8c77e177c138e59d11434676f81425999c;p=gcc.git

re PR c++/85952 (Bogus -Wunused-but-set-variable warning with array structured binding)

	PR c++/85952
	* init.c (build_aggr_init): For structured binding initialized from
	array call mark_rvalue_use on the initializer.

	* g++.dg/warn/Wunused-var-33.C: New test.

From-SVN: r260899
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index a3a443a69b9..d411be5d9d8 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2018-05-29  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/85952
+	* init.c (build_aggr_init): For structured binding initialized from
+	array call mark_rvalue_use on the initializer.
+
 2018-05-28  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	* decl2.c (start_static_storage_duration_function): Use
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 3f1e49bae21..de1bfee54bb 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -1678,6 +1678,7 @@ build_aggr_init (tree exp, tree init, int flags, tsubst_flags_t complain)
       if (VAR_P (exp) && DECL_DECOMPOSITION_P (exp))
 	{
 	  from_array = 1;
+	  init = mark_rvalue_use (init);
 	  if (init && DECL_P (init)
 	      && !(flags & LOOKUP_ONLYCONVERTING))
 	    {
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 28a28448741..d71991fb646 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2018-05-29  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/85952
+	* g++.dg/warn/Wunused-var-33.C: New test.
+
 	PR target/85918
 	* gcc.target/i386/avx512dq-pr85918.c: Add -mprefer-vector-width=512
 	and -fno-vect-cost-model options.  Add aligned(64) attribute to the
diff --git a/gcc/testsuite/g++.dg/warn/Wunused-var-33.C b/gcc/testsuite/g++.dg/warn/Wunused-var-33.C
new file mode 100644
index 00000000000..080a4f81d72
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wunused-var-33.C
@@ -0,0 +1,37 @@
+// PR c++/85952
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wunused-but-set-variable" }
+
+int
+foo ()
+{
+  int a[2] = {1, 2};	// { dg-bogus "set but not used" } */
+  auto [x, y] = a;	// { dg-warning "structured bindings only available with" "" { target c++14_down } }
+  return x + y;
+}
+
+struct S { int d, e; };
+
+int
+bar ()
+{
+  S a = {1, 2};
+  auto [x, y] = a;	// { dg-warning "structured bindings only available with" "" { target c++14_down } }
+  return x + y;
+}
+
+int
+baz ()
+{
+  S a = {1, 2};
+  auto & [x, y] = a;	// { dg-warning "structured bindings only available with" "" { target c++14_down } }
+  return x + y;
+}
+
+int
+qux ()
+{
+  int a[2] = {1, 2};
+  auto & [x, y] = a;	// { dg-warning "structured bindings only available with" "" { target c++14_down } }
+  return x + y;
+}