2009-07-08 Manuel López-Ibáñez <manu@gcc.gnu.org>

	PR c++/31246
	* gimplify.c (gimplify_expr): Propagate no_warning flag when
	gimplifying.
	* gimple (gimple_build_call_from_tree): Likewise.
	* tree-cfg.c (remove_useless_stmts_warn_notreached): Check
	no_warning flag before warning.
cp/
	* init.c (build_new_1): Set TREE_NO_WARNING for compiler-generated
	code.
	* cp-gimplify.c (genericize_eh_spec_block): Likewise.

testsuite/
	* g++.dg/warn/pr31246.C: New.
	* g++.dg/warn/pr31246-2.C: New.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@149354 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8140cc3..60d0e7e 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2009-07-08  Manuel López-Ibáñez  <manu@gcc.gnu.org>
+
+       PR c++/31246
+       * gimplify.c (gimplify_expr): Propagate no_warning flag when
+       gimplifying.
+       * gimple (gimple_build_call_from_tree): Likewise.
+       * tree-cfg.c (remove_useless_stmts_warn_notreached): Check
+       no_warning flag before warning.
+       
 2009-07-07  Manuel López-Ibáñez  <manu@gcc.gnu.org>
 
        * tree.c (set_expr_locus): Remove.

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 051faf6..3919397 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,11 @@
+2009-07-08  Manuel López-Ibáñez  <manu@gcc.gnu.org>
+
+       PR c++/31246
+       * init.c (build_new_1): Set TREE_NO_WARNING for compiler-generated
+       code.
+       * cp-gimplify.c (genericize_eh_spec_block): Likewise.
+       
+
 2009-07-07  Jason Merrill  <jason@redhat.com>
 
        PR c++/35828

diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c
index 29f4f38..fc30c06 100644 (file)
--- a/gcc/cp/cp-gimplify.c
+++ b/gcc/cp/cp-gimplify.c
@@ -153,6 +153,8 @@ genericize_eh_spec_block (tree *stmt_p)
   tree failure = build_call_n (call_unexpected_node, 1, build_exc_ptr ());
 
   *stmt_p = build_gimple_eh_filter_tree (body, allowed, failure);
+  TREE_NO_WARNING (*stmt_p) = true;
+  TREE_NO_WARNING (TREE_OPERAND (*stmt_p, 1)) = true;
 }
 
 /* Genericize an IF_STMT by turning it into a COND_EXPR.  */

diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 96dd6c1..68ffe3a 100644 (file)
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -2185,8 +2185,14 @@ build_new_1 (VEC(tree,gc) **placement, tree type, tree nelts,
          else if (stable)
            /* This is much simpler if we were able to preevaluate all of
               the arguments to the constructor call.  */
-           init_expr = build2 (TRY_CATCH_EXPR, void_type_node,
-                               init_expr, cleanup);
+           {
+             /* CLEANUP is compiler-generated, so no diagnostics.  */
+             TREE_NO_WARNING (cleanup) = true;
+             init_expr = build2 (TRY_CATCH_EXPR, void_type_node,
+                                 init_expr, cleanup);
+             /* Likewise, this try-catch is compiler-generated.  */
+             TREE_NO_WARNING (init_expr) = true;
+           }
          else
            /* Ack!  First we allocate the memory.  Then we set our sentry
               variable to true, and expand a cleanup that deletes the
@@ -2206,6 +2212,9 @@ build_new_1 (VEC(tree,gc) **placement, tree type, tree nelts,
 
              sentry = TARGET_EXPR_SLOT (begin);
 
+             /* CLEANUP is compiler-generated, so no diagnostics.  */
+             TREE_NO_WARNING (cleanup) = true;
+
              TARGET_EXPR_CLEANUP (begin)
                = build3 (COND_EXPR, void_type_node, sentry,
                          cleanup, void_zero_node);
@@ -2217,8 +2226,9 @@ build_new_1 (VEC(tree,gc) **placement, tree type, tree nelts,
                = build2 (COMPOUND_EXPR, void_type_node, begin,
                          build2 (COMPOUND_EXPR, void_type_node, init_expr,
                                  end));
+             /* Likewise, this is compiler-generated.  */
+             TREE_NO_WARNING (init_expr) = true;
            }
-
        }
     }
   else

diff --git a/gcc/gimple.c b/gcc/gimple.c
index 4f18b78..5610831 100644 (file)
--- a/gcc/gimple.c
+++ b/gcc/gimple.c
@@ -357,6 +357,7 @@ gimple_build_call_from_tree (tree t)
   gimple_call_set_return_slot_opt (call, CALL_EXPR_RETURN_SLOT_OPT (t));
   gimple_call_set_from_thunk (call, CALL_FROM_THUNK_P (t));
   gimple_call_set_va_arg_pack (call, CALL_EXPR_VA_ARG_PACK (t));
+  gimple_set_no_warning (call, TREE_NO_WARNING (t));
 
   return call;
 }

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 032228d..b20c8ac 100644 (file)
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -6787,6 +6787,7 @@ gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 
            gimplify_and_add (EH_FILTER_FAILURE (*expr_p), &failure);
            ehf = gimple_build_eh_filter (EH_FILTER_TYPES (*expr_p), failure);
+           gimple_set_no_warning (ehf, TREE_NO_WARNING (*expr_p));
            gimple_eh_filter_set_must_not_throw
              (ehf, EH_FILTER_MUST_NOT_THROW (*expr_p));
            gimplify_seq_add_stmt (pre_p, ehf);

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3f35f44..d063cbb 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2009-07-08  Manuel López-Ibáñez  <manu@gcc.gnu.org>
+       
+       PR c++/31246
+       * g++.dg/warn/pr31246.C: New.
+       * g++.dg/warn/pr31246-2.C: New.
+
 2009-07-07  Jason Merrill  <jason@redhat.com>
 
        PR c++/35828

diff --git a/gcc/testsuite/g++.dg/warn/pr31246-2.C b/gcc/testsuite/g++.dg/warn/pr31246-2.C
new file mode 100644 (file)
index 0000000..c9a4cae
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/pr31246-2.C
@@ -0,0 +1,9 @@
+// PR 31246
+// { dg-do compile }
+// { dg-options "-Wunreachable-code" }
+#include <new>
+
+int* get_ptr(void* ptr)
+{
+  return new(ptr) int();
+}

diff --git a/gcc/testsuite/g++.dg/warn/pr31246.C b/gcc/testsuite/g++.dg/warn/pr31246.C
new file mode 100644 (file)
index 0000000..f3603af
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/pr31246.C
@@ -0,0 +1,9 @@
+// PR 31246
+// { dg-do compile }
+// { dg-options "-Wunreachable-code -D_GLIBCXX_DEBUG" }
+#include <vector>
+
+int main()
+{
+  std::vector<int>::iterator a;
+}

diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index f18bb97..dd38134 100644 (file)
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -1638,6 +1638,8 @@ remove_useless_stmts_warn_notreached (gimple_seq stmts)
     {
       gimple stmt = gsi_stmt (gsi);
 
+      if (gimple_no_warning_p (stmt)) return false;
+
       if (gimple_has_location (stmt))
         {
           location_t loc = gimple_location (stmt);