From cc28fc7fe9d488a5d5afb94038eea11f0c9a7d44 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Wed, 19 Feb 2014 06:29:49 +0000 Subject: [PATCH] re PR c/60195 (Strange warnings using atomic types) PR c/60195 c/ * c-typeck.c (convert_lvalue_to_rvalue): Set TREE_NO_WARNING on tmp. Call mark_exp_read on exp.value. (build_atomic_assign): Set TREE_NO_WARNING on val and old. Set TREE_ADDRESSABLE on old instead of val. (emit_side_effect_warnings): Warn only if RHS has !TREE_NO_WARNING. testsuite/ * gcc.dg/pr60195.c: New test. From-SVN: r207873 --- gcc/c/ChangeLog | 9 ++++++ gcc/c/c-typeck.c | 9 +++++- gcc/testsuite/ChangeLog | 5 +++ gcc/testsuite/gcc.dg/pr60195.c | 56 ++++++++++++++++++++++++++++++++++ 4 files changed, 78 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/pr60195.c diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog index 8d11ad63e40..32d724265dc 100644 --- a/gcc/c/ChangeLog +++ b/gcc/c/ChangeLog @@ -1,3 +1,12 @@ +2014-02-19 Marek Polacek + + PR c/60195 + * c-typeck.c (convert_lvalue_to_rvalue): Set TREE_NO_WARNING on tmp. + Call mark_exp_read on exp.value. + (build_atomic_assign): Set TREE_NO_WARNING on val and old. Set + TREE_ADDRESSABLE on old instead of val. + (emit_side_effect_warnings): Warn only if RHS has !TREE_NO_WARNING. + 2014-02-07 Prathamesh Kulkarni * c-parser.c (c_parser_get_builtin_args): Replace calls to diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c index da6a6fc9f98..2b542903ba9 100644 --- a/gcc/c/c-typeck.c +++ b/gcc/c/c-typeck.c @@ -2009,6 +2009,7 @@ convert_lvalue_to_rvalue (location_t loc, struct c_expr exp, tmp = create_tmp_var (nonatomic_type, NULL); tmp_addr = build_unary_op (loc, ADDR_EXPR, tmp, 0); TREE_ADDRESSABLE (tmp) = 1; + TREE_NO_WARNING (tmp) = 1; /* Issue __atomic_load (&expr, &tmp, SEQ_CST); */ fndecl = builtin_decl_explicit (BUILT_IN_ATOMIC_LOAD); @@ -2017,6 +2018,9 @@ convert_lvalue_to_rvalue (location_t loc, struct c_expr exp, params->quick_push (seq_cst); func_call = build_function_call_vec (loc, vNULL, fndecl, params, NULL); + /* EXPR is always read. */ + mark_exp_read (exp.value); + /* Return tmp which contains the value loaded. */ exp.value = build2 (COMPOUND_EXPR, nonatomic_type, func_call, tmp); } @@ -3615,6 +3619,7 @@ build_atomic_assign (location_t loc, tree lhs, enum tree_code modifycode, nonatomic_rhs_type = build_qualified_type (rhs_type, TYPE_UNQUALIFIED); val = create_tmp_var (nonatomic_rhs_type, NULL); TREE_ADDRESSABLE (val) = 1; + TREE_NO_WARNING (val) = 1; rhs = build2 (MODIFY_EXPR, nonatomic_rhs_type, val, rhs); SET_EXPR_LOCATION (rhs, loc); add_stmt (rhs); @@ -3643,7 +3648,8 @@ build_atomic_assign (location_t loc, tree lhs, enum tree_code modifycode, /* Create the variables and labels required for the op= form. */ old = create_tmp_var (nonatomic_lhs_type, NULL); old_addr = build_unary_op (loc, ADDR_EXPR, old, 0); - TREE_ADDRESSABLE (val) = 1; + TREE_ADDRESSABLE (old) = 1; + TREE_NO_WARNING (old) = 1; newval = create_tmp_var (nonatomic_lhs_type, NULL); newval_addr = build_unary_op (loc, ADDR_EXPR, newval, 0); @@ -9661,6 +9667,7 @@ emit_side_effect_warnings (location_t loc, tree expr) if (!TREE_SIDE_EFFECTS (r) && !VOID_TYPE_P (TREE_TYPE (r)) && !CONVERT_EXPR_P (r) + && !TREE_NO_WARNING (r) && !TREE_NO_WARNING (expr)) warning_at (cloc, OPT_Wunused_value, "right-hand operand of comma expression has no effect"); diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 4e92a85a156..e246657c5ee 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2014-02-19 Marek Polacek + + PR c/60195 + * gcc.dg/pr60195.c: New test. + 2014-02-19 Paul Pluzhnikov * gcc.dg/vect/no-vfa-vect-depend-2.c (main1): Fix buffer diff --git a/gcc/testsuite/gcc.dg/pr60195.c b/gcc/testsuite/gcc.dg/pr60195.c new file mode 100644 index 00000000000..0a50a30be25 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr60195.c @@ -0,0 +1,56 @@ +/* PR c/60195 */ +/* { dg-do compile } */ +/* { dg-options "-std=c11 -Wpedantic -Wall" } */ + +typedef _Atomic int atomic_int; + +atomic_int +fn1 (void) +{ + atomic_int y = 0; + return y; +} + +atomic_int +fn2 (void) +{ + atomic_int y = 0; + y; + return y; +} + +atomic_int +fn3 (void) +{ + atomic_int y = 0; + y++; + return y; +} + +void +fn4 (void) +{ + atomic_int y; + y = 0; + (void) y; +} + +void +fn5 (void) +{ + atomic_int y = 0; /* { dg-warning "unused variable" } */ +} + +void +fn6 (void) +{ + atomic_int y; /* { dg-warning "set but not used" } */ + y = 0; +} + +void +fn7 (void) +{ + atomic_int y = 0; + y++; +} -- 2.30.2