re PR sanitizer/59331 (ubsan gives extra warnings with vla.)

	PR sanitizer/59331
cp/
	* decl.c (compute_array_index_type): Don't build COMPOUND_EXPR for
	instrumentation.
testsuite/
	* g++.dg/ubsan/pr59331.C: New test.
	* g++.dg/ubsan/cxx1y-vla.C: Enable -Wall -Wno-unused-variable.
	Disable the -w option.
	* c-c++-common/ubsan/vla-1.c: Likewise.
	* c-c++-common/ubsan/vla-2.c: Likewise.
	* c-c++-common/ubsan/vla-3.c: Don't use the -w option.

From-SVN: r205544

gcc/cp/ChangeLog

+2013-11-29  Marek Polacek  <polacek@redhat.com>
+
+	PR sanitizer/59331
+	* decl.c (compute_array_index_type): Don't build COMPOUND_EXPR for
+	instrumentation.
+
 2013-11-28  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/59297

gcc/cp/decl.c

@@ -8434,8 +8434,7 @@ compute_array_index_type (tree name, tree size, tsubst_flags_t complain)
 		 LE_EXPR rather than LT_EXPR.  */
 	      tree t = fold_build2 (PLUS_EXPR, TREE_TYPE (itype), itype,
 				    build_one_cst (TREE_TYPE (itype)));
-	      t = fold_build2 (COMPOUND_EXPR, TREE_TYPE (t),
-			       ubsan_instrument_vla (input_location, t), t);
+	      t = ubsan_instrument_vla (input_location, t);
 	      finish_expr_stmt (t);
 	    }
 	}

gcc/testsuite/ChangeLog

+2013-11-29  Marek Polacek  <polacek@redhat.com>
+
+	PR sanitizer/59331
+	* g++.dg/ubsan/pr59331.C: New test.
+	* g++.dg/ubsan/cxx1y-vla.C: Enable -Wall -Wno-unused-variable.
+	Disable the -w option.
+	* c-c++-common/ubsan/vla-1.c: Likewise.
+	* c-c++-common/ubsan/vla-2.c: Likewise.
+	* c-c++-common/ubsan/vla-3.c: Don't use the -w option.
+
 2013-11-29  Joseph Myers  <joseph@codesourcery.com>
 
 	PR c/42262

gcc/testsuite/c-c++-common/ubsan/vla-1.c

 /* { dg-do run } */
-/* { dg-options "-fsanitize=vla-bound -w" } */
+/* { dg-options "-fsanitize=vla-bound -Wall -Wno-unused-variable" } */
 
 static int
 bar (void)

gcc/testsuite/c-c++-common/ubsan/vla-2.c

 /* { dg-do run } */
-/* { dg-options "-fsanitize=vla-bound -w" } */
+/* { dg-options "-fsanitize=vla-bound -Wall -Wno-unused-variable" } */
 
 int
 main (void)

gcc/testsuite/c-c++-common/ubsan/vla-3.c

 /* { dg-do run } */
-/* { dg-options "-fsanitize=vla-bound -w" } */
+/* { dg-options "-fsanitize=vla-bound" } */
 
 /* Don't instrument the arrays here.  */
 int

gcc/testsuite/g++.dg/ubsan/cxx1y-vla.C

 /* { dg-do run } */
-/* { dg-options "-fsanitize=vla-bound -w -std=c++1y" } */
+/* { dg-options "-fsanitize=vla-bound -Wall -Wno-unused-variable -std=c++1y" } */
 /* { dg-shouldfail "ubsan" } */
 
 int

gcc/testsuite/g++.dg/ubsan/pr59331.C

+/* { dg-do compile } */
+/* { dg-options "-fsanitize=vla-bound -Wall -Wno-unused-variable" } */
+
+void foo(int i)
+{
+  /* Don't warn here with "value computed is not used".  */
+  char a[i];
+}