From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 30 May 2017 07:53:35 +0000 (+0200)
Subject: backport: re PR c++/78949 (incorrect "unused variable" warning with SSE2)
X-Git-Tag: releases/gcc-5.5.0~275
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=01a4072b28f06bff939d1166c626bf99f0e19970;p=thirdparty%2Fgcc.git

backport: re PR c++/78949 (incorrect "unused variable" warning with SSE2)

	Backported from mainline
	2017-01-04  Jakub Jelinek  <jakub@redhat.com>

	PR c++/78949
	* typeck.c (cp_build_unary_op): Call mark_rvalue_use on arg if it has
	vector type.

	* c-c++-common/Wunused-var-16.c: New test.

From-SVN: r248637
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index b0fbf05a9996..52a1d0e5b906 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,6 +1,12 @@
 2017-05-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2017-01-04  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/78949
+	* typeck.c (cp_build_unary_op): Call mark_rvalue_use on arg if it has
+	vector type.
+
 	2016-12-02  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/78649
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 669f54141387..e3ba6077c09e 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -5700,6 +5700,8 @@ cp_build_unary_op (enum tree_code code, tree xarg, int noconvert,
 	errstring = _("wrong type argument to bit-complement");
       else if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg)))
 	arg = cp_perform_integral_promotions (arg, complain);
+      else if (!noconvert && VECTOR_TYPE_P (TREE_TYPE (arg)))
+	arg = mark_rvalue_use (arg);
       break;
 
     case ABS_EXPR:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 51e63c6bd2a3..9424d657d507 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2017-05-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2017-01-04  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/78949
+	* c-c++-common/Wunused-var-16.c: New test.
+
 	2016-12-21  Jakub Jelinek  <jakub@redhat.com>
 
 	PR fortran/78866
diff --git a/gcc/testsuite/c-c++-common/Wunused-var-16.c b/gcc/testsuite/c-c++-common/Wunused-var-16.c
new file mode 100644
index 000000000000..98e66a723809
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Wunused-var-16.c
@@ -0,0 +1,15 @@
+/* PR c++/78949 */
+/* { dg-do compile } */
+/* { dg-options "-Wunused" } */
+
+typedef unsigned char V __attribute__((vector_size(16)));
+V v;
+
+void
+foo ()
+{
+  V y = {};
+  V x = {};	// { dg-bogus "set but not used" }
+  y &= ~x;
+  v = y;
+}