From: paolo <paolo@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Wed, 12 Jun 2013 21:36:36 +0000 (+0000)
Subject: /cp
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a8b52ce38f3056e464457ba1e95efa25a8f08d07;p=thirdparty%2Fgcc.git

/cp
2013-06-12  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/38958
	* decl.c (poplevel): For the benefit of -Wunused-variable see
	through references.

/testsuite
2013-06-12  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/38958
	* g++.dg/warn/Wunused-var-20.C: New.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@200042 138bc75d-0d04-0410-961f-82ee72b054a4
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 2c9398288cd0..48a9310bddcc 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2013-06-12  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/38958
+	* decl.c (poplevel): For the benefit of -Wunused-variable see
+	through references.
+
 2013-06-12  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* parser.c (cp_parser_nested_name_specifier_opt): Fix typo in comment.
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 7825c73e0d7e..9eb1d12ceb2e 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -622,17 +622,20 @@ poplevel (int keep, int reverse, int functionbody)
 	   push_local_binding where the list of decls returned by
 	   getdecls is built.  */
 	decl = TREE_CODE (d) == TREE_LIST ? TREE_VALUE (d) : d;
+	// See through references for improved -Wunused-variable (PR 38958).
+	tree type = non_reference (TREE_TYPE (decl));
 	if (VAR_P (decl)
 	    && (! TREE_USED (decl) || !DECL_READ_P (decl))
 	    && ! DECL_IN_SYSTEM_HEADER (decl)
 	    && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl)
-	    && TREE_TYPE (decl) != error_mark_node
-	    && (!CLASS_TYPE_P (TREE_TYPE (decl))
-		|| !TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (decl))))
+	    && type != error_mark_node
+	    && (!CLASS_TYPE_P (type)
+		|| !TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type)))
 	  {
 	    if (! TREE_USED (decl))
 	      warning (OPT_Wunused_variable, "unused variable %q+D", decl);
 	    else if (DECL_CONTEXT (decl) == current_function_decl
+		     // For -Wunused-but-set-variable leave references alone.
 		     && TREE_CODE (TREE_TYPE (decl)) != REFERENCE_TYPE
 		     && errorcount == unused_but_set_errorcount)
 	      {
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 51143cbdad1f..b167e4c3d479 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2013-06-12  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/38958
+	* g++.dg/warn/Wunused-var-20.C: New.
+
 2013-06-12  Richard Sandiford  <rdsandiford@googlemail.com>
 
 	* gcc.target/mips/mips.exp: Handle -f{no-,}common.
diff --git a/gcc/testsuite/g++.dg/warn/Wunused-var-20.C b/gcc/testsuite/g++.dg/warn/Wunused-var-20.C
new file mode 100644
index 000000000000..792c25369c74
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wunused-var-20.C
@@ -0,0 +1,19 @@
+// PR c++/38958
+// { dg-options "-Wunused" }
+
+volatile int g;
+
+struct Lock
+{
+  ~Lock() { g = 0; }
+};
+
+Lock AcquireLock() { return Lock(); }
+
+int main()
+{
+  const Lock& lock = AcquireLock();
+  g = 1;
+  g = 2;
+  g = 3;
+}