From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 19 Jul 2011 12:48:50 +0000 (+0200)
Subject: backport: re PR c/49120 (bogus "value computed is not used" warning (variable-length... 
X-Git-Tag: releases/gcc-4.5.4~530
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=525499ca29f87493e0dfd9fc1cc3db0f3d25f059;p=thirdparty%2Fgcc.git

backport: re PR c/49120 (bogus "value computed is not used" warning (variable-length array in compound statement))

	Backport from mainline
	2011-05-23  Jakub Jelinek  <jakub@redhat.com>

	PR c/49120
	* c-decl.c (start_decl): Convert expr to void_type_node.

	* gcc.dg/pr49120.c: New test.

From-SVN: r176450
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0ccc165125d7..d59d4a58ae23 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -3,6 +3,9 @@
 	Backport from mainline
 	2011-05-23  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c/49120
+	* c-decl.c (start_decl): Convert expr to void_type_node.
+
 	PR middle-end/48973
 	* expr.c (expand_expr_real_2) <case LT_EXPR>: If do_store_flag
 	failed and the comparison has a single bit signed type, use
diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index 9763b37ff275..abb4bdeee2af 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -3909,7 +3909,7 @@ start_decl (struct c_declarator *declarator, struct c_declspecs *declspecs,
     return 0;
 
   if (expr)
-    add_stmt (expr);
+    add_stmt (fold_convert (void_type_node, expr));
 
   if (TREE_CODE (decl) != FUNCTION_DECL && MAIN_NAME_P (DECL_NAME (decl)))
     warning (OPT_Wmain, "%q+D is usually a function", decl);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 5d1e7d5f3a90..0778cdd96a25 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -3,6 +3,9 @@
 	Backport from mainline
 	2011-05-23  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c/49120
+	* c-decl.c (start_decl): Convert expr to void_type_node.
+
 	PR middle-end/48973
 	* gcc.c-torture/execute/pr48973-1.c: New test.
 	* gcc.c-torture/execute/pr48973-2.c: New test.
diff --git a/gcc/testsuite/gcc.dg/pr49120.c b/gcc/testsuite/gcc.dg/pr49120.c
new file mode 100644
index 000000000000..1a65222cfeca
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr49120.c
@@ -0,0 +1,11 @@
+/* PR c/49120 */
+/* { dg-do compile } */
+/* { dg-options "-Wall" } */
+
+int
+main ()
+{
+  int a = 1;
+  int c = ({ char b[a + 1]; b[0] = 0; b[0]; });
+  return c;
+}