From 056928b248b7e3f879c2b3ac4be935e67ad3a09a Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Tue, 11 May 2010 20:12:28 +0200 Subject: re PR c++/44062 ((void)var; doesn't prevent 'set but not used' warning) PR c++/44062 * c-parser.c (c_parser_expression): Mark LHS of a comma expression as read if it is a decl, handled component or COMPOUND_EXPR with that on the RHS. * c-typeck.c (c_process_expr_stmt): Mark RHS of COMPOUND_EXPR if it is a decl or handled component. * semantics.c (finish_expr_stmt): Don't call mark_exp_read here... * cvt.c (convert_to_void): ... but here. If expr is a COMPOUND_EXPR, look at its second operand. * c-c++-common/Wunused-var-7.c: New test. * g++.dg/warn/Wunused-var-9.C: New test. From-SVN: r159286 --- gcc/cp/cvt.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'gcc/cp/cvt.c') diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c index b357084..efef5c2 100644 --- a/gcc/cp/cvt.c +++ b/gcc/cp/cvt.c @@ -1,6 +1,6 @@ /* Language-level data type conversion for GNU C++. Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, - 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 + 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. Hacked by Michael Tiemann (tiemann@cygnus.com) @@ -822,9 +822,23 @@ ocp_convert (tree type, tree expr, int convtype, int flags) tree convert_to_void (tree expr, const char *implicit, tsubst_flags_t complain) { + tree exprv; + if (expr == error_mark_node || TREE_TYPE (expr) == error_mark_node) return error_mark_node; + + exprv = expr; + while (TREE_CODE (exprv) == COMPOUND_EXPR) + exprv = TREE_OPERAND (exprv, 1); + if (DECL_P (exprv) || handled_component_p (exprv)) + /* Expr is not being 'used' here, otherwise we whould have + called mark_{rl}value_use use here, which would have in turn + called mark_exp_read. Rather, we call mark_exp_read directly + to avoid some warnings when + -Wunused-but-set-{variable,parameter} is in effect. */ + mark_exp_read (exprv); + if (!TREE_TYPE (expr)) return expr; if (invalid_nonstatic_memfn_p (expr, complain)) -- cgit v1.1