c-common.c (empty_if_body_warning): Remove.

2008-09-30  Paolo Bonzini  <bonzini@gnu.org>

	* c-common.c (empty_if_body_warning): Remove.
	* c-common.h (empty_if_body_warning): Remove.
	* c-parser.c (c_parser_if_body, c_parser_else_body): Implement
	here the -Wempty-body warning for `if' and `else' statements.
	* c-typeck.c (c_finish_if_stmt): Do not call empty_body_warning.

cp:
2008-09-30  Paolo Bonzini  <bonzini@gnu.org>

	* parser.c (cp_parser_selection_statement): Implement here the
	-Wempty-body warning for `if' and `else' statements.
	* semantics.c (finish_if_stmt): Do not call empty_body_warning.

testsuite:
2008-09-30  Paolo Bonzini  <bonzini@gnu.org>

	* g++.dg/warn/if-empty-1.C: Copy from gcc.dg/if-empty-1.c.

From-SVN: r140780

10 files changed, 70 insertions, 31 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5a9b482..68de57a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2008-09-30  Paolo Bonzini  <bonzini@gnu.org>
+
+	* c-common.c (empty_if_body_warning): Remove.
+	* c-common.h (empty_if_body_warning): Remove.
+	* c-parser.c (c_parser_if_body, c_parser_else_body): Implement
+	here the -Wempty-body warning for `if' and `else' statements.
+	* c-typeck.c (c_finish_if_stmt): Do not call empty_body_warning.
+
 2008-09-29  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* config/i386/i386.opt: Add msse2avx.
diff --git a/gcc/c-common.c b/gcc/c-common.c
index 5d69211..7665b62 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -1291,31 +1291,6 @@ strict_aliasing_warning (tree otype, tree type, tree expr)
   return false;
 }
 
-/* Print a warning about if (); or if () .. else; constructs
-   via the special empty statement node that we create.  INNER_THEN
-   and INNER_ELSE are the statement lists of the if and the else
-   block.  */
-
-void
-empty_if_body_warning (tree inner_then, tree inner_else)
-{
-  if (TREE_CODE (inner_then) == STATEMENT_LIST
-      && STATEMENT_LIST_TAIL (inner_then))
-    inner_then = STATEMENT_LIST_TAIL (inner_then)->stmt;
-
-  if (inner_else && TREE_CODE (inner_else) == STATEMENT_LIST
-      && STATEMENT_LIST_TAIL (inner_else))
-    inner_else = STATEMENT_LIST_TAIL (inner_else)->stmt;
-
-  if (IS_EMPTY_STMT (inner_then) && !inner_else)
-    warning (OPT_Wempty_body, "%Hsuggest braces around empty body "
-             "in an %<if%> statement", EXPR_LOCUS (inner_then));
-
-  else if (inner_else && IS_EMPTY_STMT (inner_else))
-    warning (OPT_Wempty_body, "%Hsuggest braces around empty body "
-             "in an %<else%> statement", EXPR_LOCUS (inner_else));
-}
-
 /* Warn for unlikely, improbable, or stupid DECL declarations
    of `main'.  */
 
diff --git a/gcc/c-common.h b/gcc/c-common.h
index 15ea573..622100a 100644
--- a/gcc/c-common.h
+++ b/gcc/c-common.h
@@ -726,7 +726,6 @@ struct varray_head_tag;
 extern void constant_expression_warning (tree);
 extern void constant_expression_error (tree);
 extern bool strict_aliasing_warning (tree, tree, tree);
-extern void empty_if_body_warning (tree, tree);
 extern void warnings_for_convert_and_check (tree, tree, tree);
 extern tree convert_and_check (tree, tree);
 extern void overflow_warning (tree);
diff --git a/gcc/c-parser.c b/gcc/c-parser.c
index 2b64c86..9597660 100644
--- a/gcc/c-parser.c
+++ b/gcc/c-parser.c
@@ -3858,8 +3858,12 @@ c_parser_if_body (c_parser *parser, bool *if_p)
   *if_p = c_parser_next_token_is_keyword (parser, RID_IF);
   if (c_parser_next_token_is (parser, CPP_SEMICOLON))
     {
+      location_t loc = c_parser_peek_token (parser)->location;
       add_stmt (build_empty_stmt ());
       c_parser_consume_token (parser);
+      if (!c_parser_next_token_is_keyword (parser, RID_ELSE))
+	warning_at (loc, OPT_Wempty_body,
+		    "suggest braces around empty body in an %<if%> statement");
     }
   else if (c_parser_next_token_is (parser, CPP_OPEN_BRACE))
     add_stmt (c_parser_compound_statement (parser));
@@ -3883,6 +3887,9 @@ c_parser_else_body (c_parser *parser)
     c_parser_label (parser);
   if (c_parser_next_token_is (parser, CPP_SEMICOLON))
     {
+      warning_at (c_parser_peek_token (parser)->location,
+		  OPT_Wempty_body,
+	         "suggest braces around empty body in an %<else%> statement");
       add_stmt (build_empty_stmt ());
       c_parser_consume_token (parser);
     }
diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index 1424405..c6474ed 100644
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -7440,8 +7440,6 @@ c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
 		  &if_locus);
     }
 
-  empty_if_body_warning (then_block, else_block);
-
   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
   SET_EXPR_LOCATION (stmt, if_locus);
   add_stmt (stmt);
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 8c722d8..5e5c742 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2008-09-30  Paolo Bonzini  <bonzini@gnu.org>
+
+	* parser.c (cp_parser_selection_statement): Implement here the
+	-Wempty-body warning for `if' and `else' statements.
+	* semantics.c (finish_if_stmt): Do not call empty_body_warning.
+
 2008-09-25  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/37649
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index f28c76d..c368a1c 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -7155,7 +7155,17 @@ cp_parser_selection_statement (cp_parser* parser, bool *if_p)
 	    /* Parse the then-clause.  */
 	    in_statement = parser->in_statement;
 	    parser->in_statement |= IN_IF_STMT;
-	    cp_parser_implicitly_scoped_statement (parser, &nested_if);
+	    if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
+	      {
+	        location_t loc = cp_lexer_peek_token (parser->lexer)->location;
+		add_stmt (build_empty_stmt ());
+		cp_lexer_consume_token (parser->lexer);
+	        if (!cp_lexer_next_token_is_keyword (parser->lexer, RID_ELSE))
+		  warning_at (loc, OPT_Wempty_body, "suggest braces around "
+			      "empty body in an %<if%> statement");
+	      }
+	    else
+	      cp_parser_implicitly_scoped_statement (parser, &nested_if);
 	    parser->in_statement = in_statement;
 
 	    finish_then_clause (statement);
@@ -7168,7 +7178,17 @@ cp_parser_selection_statement (cp_parser* parser, bool *if_p)
 		cp_lexer_consume_token (parser->lexer);
 		begin_else_clause (statement);
 		/* Parse the else-clause.  */
-		cp_parser_implicitly_scoped_statement (parser, NULL);
+	        if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
+	          {
+		    warning_at (cp_lexer_peek_token (parser->lexer)->location,
+				OPT_Wempty_body, "suggest braces around "
+			        "empty body in an %<else%> statement");
+		    add_stmt (build_empty_stmt ());
+		    cp_lexer_consume_token (parser->lexer);
+		  }
+		else
+		  cp_parser_implicitly_scoped_statement (parser, NULL);
+
 		finish_else_clause (statement);
 
 		/* If we are currently parsing a then-clause, then
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 176a7fd..13e9a0f 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -695,7 +695,6 @@ finish_if_stmt (tree if_stmt)
   TREE_CHAIN (if_stmt) = NULL;
   add_stmt (do_poplevel (scope));
   finish_stmt ();
-  empty_if_body_warning (THEN_CLAUSE (if_stmt), ELSE_CLAUSE (if_stmt));
 }
 
 /* Begin a while-statement.  Returns a newly created WHILE_STMT if
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index df91766..28086b3 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,9 @@
 2008-09-30  Paolo Bonzini  <bonzini@gnu.org>
 
+	* g++.dg/warn/if-empty-1.C: Copy from gcc.dg/if-empty-1.c.
+
+2008-09-30  Paolo Bonzini  <bonzini@gnu.org>
+
 	PR testsuite/36891
 	PR testsuite/37675
 	* gcc.dg/torture/pr36891.c: Add -msse on 32-bit i386.
diff --git a/gcc/testsuite/g++.dg/warn/if-empty-1.C b/gcc/testsuite/g++.dg/warn/if-empty-1.C
new file mode 100644
index 0000000..b29a6cb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/if-empty-1.C
@@ -0,0 +1,23 @@
+/* Test diagnostics for empty bodies in if / else.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-Wempty-body" } */
+
+void
+f (int x)
+{
+  if (x)
+    ; /* { dg-warning "suggest braces around empty body in an" } */
+  if (x)
+    ; /* By design we don't warn in this case.  */
+  else
+    (void)0;
+  if (x)
+    (void)0;
+  else
+    ; /* { dg-warning "suggest braces around empty body in an" } */
+  if (x)
+    (void)0;
+  else
+    (void)0;
+}