re PR c++/44780 (Bogus set-but-not-used variable warning)

	PR c++/44780
	* typeck.c (convert_for_assignment): When converting a convertible
	vector type or objc++ types, call mark_rvalue_use.
	* typeck2.c (build_m_component_ref): Use return values from
	mark_rvalue_use or mark_lvalue_use.
	* class.c (build_base_path): Likewise.
	* call.c (build_conditional_expr): Likewise.

	* c-c++-common/Wunused-var-12.c: New test.

From-SVN: r161742

7 files changed, 53 insertions, 7 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 3b2764d..33aee8a 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,13 @@
+2010-07-02  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/44780
+	* typeck.c (convert_for_assignment): When converting a convertible
+	vector type or objc++ types, call mark_rvalue_use.
+	* typeck2.c (build_m_component_ref): Use return values from
+	mark_rvalue_use or mark_lvalue_use.
+	* class.c (build_base_path): Likewise.
+	* call.c (build_conditional_expr): Likewise.
+
 2010-07-02  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/44039
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index d03ecb1..c4f3e95 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -3861,8 +3861,8 @@ build_conditional_expr (tree arg1, tree arg2, tree arg3,
       && same_type_p (arg2_type, arg3_type))
     {
       result_type = arg2_type;
-      mark_lvalue_use (arg2);
-      mark_lvalue_use (arg3);
+      arg2 = mark_lvalue_use (arg2);
+      arg3 = mark_lvalue_use (arg3);
       goto valid_operands;
     }
 
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index a2ed863..3c4830e 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -284,7 +284,7 @@ build_base_path (enum tree_code code,
     /* This must happen before the call to save_expr.  */
     expr = cp_build_unary_op (ADDR_EXPR, expr, 0, tf_warning_or_error);
   else
-    mark_rvalue_use (expr);
+    expr = mark_rvalue_use (expr);
 
   offset = BINFO_OFFSET (binfo);
   fixed_type_p = resolves_to_fixed_type_p (expr, &nonnull);
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 20345b55..ec0b06d 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -7211,7 +7211,10 @@ convert_for_assignment (tree type, tree rhs,
 
   if (TREE_CODE (type) == VECTOR_TYPE && coder == VECTOR_TYPE
       && vector_types_convertible_p (type, rhstype, true))
-    return convert (type, rhs);
+    {
+      rhs = mark_rvalue_use (rhs);
+      return convert (type, rhs);
+    }
 
   if (rhs == error_mark_node || rhstype == error_mark_node)
     return error_mark_node;
@@ -7255,7 +7258,10 @@ convert_for_assignment (tree type, tree rhs,
 	}
 
       if (objc_compare_types (type, rhstype, parmno, rname))
-	return convert (type, rhs);
+	{
+	  rhs = mark_rvalue_use (rhs);
+	  return convert (type, rhs);
+	}
     }
 
   /* [expr.ass]
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index f62bbb5..bdc14c7 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -1478,8 +1478,8 @@ build_m_component_ref (tree datum, tree component)
   if (error_operand_p (datum) || error_operand_p (component))
     return error_mark_node;
 
-  mark_lvalue_use (datum);
-  mark_rvalue_use (component);
+  datum = mark_lvalue_use (datum);
+  component = mark_rvalue_use (component);
 
   ptrmem_type = TREE_TYPE (component);
   if (!TYPE_PTR_TO_MEMBER_P (ptrmem_type))
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 33a1cae..09e56fb 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2010-07-02  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/44780
+	* c-c++-common/Wunused-var-12.c: New test.
+
 2010-07-02  Bernd Schmidt  <bernds@codesourcery.com>
 
 	PR target/42835
diff --git a/gcc/testsuite/c-c++-common/Wunused-var-12.c b/gcc/testsuite/c-c++-common/Wunused-var-12.c
new file mode 100644
index 0000000..312680a
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Wunused-var-12.c
@@ -0,0 +1,25 @@
+/* PR c++/44780 */
+/* { dg-do compile } */
+/* { dg-options "-Wunused" } */
+
+typedef double vec __attribute__ ((__vector_size__ (16)));
+vec c, d;
+
+void
+foo (void)
+{
+  vec a;
+  vec b;
+  a = c;
+  b = a;
+  d = b;
+}
+
+void
+bar (void)
+{
+  vec a;
+  vec b;	/* { dg-warning "set but not used" } */
+  a = c;
+  b = a;
+}