static void
cp_gimplify_init_expr (tree *expr_p, tree *pre_p, tree *post_p)
{
tree from = TREE_OPERAND (*expr_p, 1);
tree to = TREE_OPERAND (*expr_p, 0);
tree sub;
/* What about code that pulls out the temp and uses it elsewhere? I
think that such code never uses the TARGET_EXPR as an initializer. If
I'm wrong, we'll abort because the temp won't have any RTL. In that
case, I guess we'll need to replace references somehow. */
if (TREE_CODE (from) == TARGET_EXPR)
from = TARGET_EXPR_INITIAL (from);
/* Look through any COMPOUND_EXPRs, since build_compound_expr pushes them
inside the TARGET_EXPR. */
sub = expr_last (from);
/* If we are initializing from an AGGR_INIT_EXPR, drop the INIT_EXPR and
replace the slot operand with our target.
Should we add a target parm to gimplify_expr instead? No, as in this
case we want to replace the INIT_EXPR. */
if (TREE_CODE (sub) == AGGR_INIT_EXPR)
{
gimplify_expr (&to, pre_p, post_p, is_gimple_lvalue, fb_lvalue);
TREE_OPERAND (sub, 2) = to;
*expr_p = from;
/* The initialization is now a side-effect, so the container can
become void. */
if (from != sub)
TREE_TYPE (from) = void_type_node;
}
}
bool
cilk_detect_spawn_and_unwrap (tree *exp0)
{
tree exp = *exp0;
if (!TREE_SIDE_EFFECTS (exp))
return false;
/* Strip off any conversion to void. It does not affect whether spawn
is supported here. */
if (TREE_CODE (exp) == CONVERT_EXPR && VOID_TYPE_P (TREE_TYPE (exp)))
exp = TREE_OPERAND (exp, 0);
if (TREE_CODE (exp) == MODIFY_EXPR || TREE_CODE (exp) == INIT_EXPR)
exp = TREE_OPERAND (exp, 1);
while (cilk_ignorable_spawn_rhs_op (exp))
exp = TREE_OPERAND (exp, 0);
if (TREE_CODE (exp) == TARGET_EXPR)
if (TARGET_EXPR_INITIAL (exp)
&& TREE_CODE (TARGET_EXPR_INITIAL (exp)) != AGGR_INIT_EXPR)
exp = TARGET_EXPR_INITIAL (exp);
/* Happens with C++ TARGET_EXPR. */
if (exp == NULL_TREE)
return false;
while (TREE_CODE (exp) == CLEANUP_POINT_EXPR || TREE_CODE (exp) == EXPR_STMT)
exp = TREE_OPERAND (exp, 0);
/* Now we should have a CALL_EXPR with a CILK_SPAWN_STMT wrapper around
it, or return false. */
if (recognize_spawn (exp, exp0))
return true;
return false;
}
tree
convert_to_void (tree expr, const char *implicit, tsubst_flags_t complain)
{
if (expr == error_mark_node
|| TREE_TYPE (expr) == error_mark_node)
return error_mark_node;
if (!TREE_TYPE (expr))
return expr;
if (invalid_nonstatic_memfn_p (expr, complain))
return error_mark_node;
if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR)
{
if (complain & tf_error)
error ("pseudo-destructor is not called");
return error_mark_node;
}
if (VOID_TYPE_P (TREE_TYPE (expr)))
return expr;
switch (TREE_CODE (expr))
{
case COND_EXPR:
{
/* The two parts of a cond expr might be separate lvalues. */
tree op1 = TREE_OPERAND (expr,1);
tree op2 = TREE_OPERAND (expr,2);
tree new_op1 = convert_to_void
(op1, (implicit && !TREE_SIDE_EFFECTS (op2)
? "second operand of conditional" : NULL), complain);
tree new_op2 = convert_to_void
(op2, (implicit && !TREE_SIDE_EFFECTS (op1)
? "third operand of conditional" : NULL), complain);
expr = build3 (COND_EXPR, TREE_TYPE (new_op1),
TREE_OPERAND (expr, 0), new_op1, new_op2);
break;
}
case COMPOUND_EXPR:
{
/* The second part of a compound expr contains the value. */
tree op1 = TREE_OPERAND (expr,1);
tree new_op1 = convert_to_void
(op1, (implicit && !TREE_NO_WARNING (expr)
? "right-hand operand of comma" : NULL), complain);
if (new_op1 != op1)
{
tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1),
TREE_OPERAND (expr, 0), new_op1);
expr = t;
}
break;
}
case NON_LVALUE_EXPR:
case NOP_EXPR:
/* These have already decayed to rvalue. */
break;
case CALL_EXPR: /* We have a special meaning for volatile void fn(). */
break;
case INDIRECT_REF:
{
tree type = TREE_TYPE (expr);
int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0)))
== REFERENCE_TYPE;
int is_volatile = TYPE_VOLATILE (type);
int is_complete = COMPLETE_TYPE_P (complete_type (type));
/* Can't load the value if we don't know the type. */
if (is_volatile && !is_complete)
{
if (complain & tf_warning)
warning (0, "object of incomplete type %qT will not be accessed in %s",
type, implicit ? implicit : "void context");
}
/* Don't load the value if this is an implicit dereference, or if
the type needs to be handled by ctors/dtors. */
else if (is_volatile && (is_reference || TREE_ADDRESSABLE (type)))
{
if (complain & tf_warning)
warning (0, "object of type %qT will not be accessed in %s",
TREE_TYPE (TREE_OPERAND (expr, 0)),
implicit ? implicit : "void context");
}
if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type))
expr = TREE_OPERAND (expr, 0);
break;
}
case VAR_DECL:
{
/* External variables might be incomplete. */
tree type = TREE_TYPE (expr);
int is_complete = COMPLETE_TYPE_P (complete_type (type));
if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning))
warning (0, "object %qE of incomplete type %qT will not be accessed in %s",
expr, type, implicit ? implicit : "void context");
break;
}
case TARGET_EXPR:
/* Don't bother with the temporary object returned from a function if
we don't use it and don't need to destroy it. We'll still
allocate space for it in expand_call or declare_return_variable,
but we don't need to track it through all the tree phases. */
if (TARGET_EXPR_IMPLICIT_P (expr)
&& TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr)))
{
tree init = TARGET_EXPR_INITIAL (expr);
if (TREE_CODE (init) == AGGR_INIT_EXPR
&& !AGGR_INIT_VIA_CTOR_P (init))
{
tree fn = AGGR_INIT_EXPR_FN (init);
expr = build_call_array (TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))),
fn,
aggr_init_expr_nargs (init),
AGGR_INIT_EXPR_ARGP (init));
}
}
break;
default:;
}
{
tree probe = expr;
if (TREE_CODE (probe) == ADDR_EXPR)
probe = TREE_OPERAND (expr, 0);
if (type_unknown_p (probe))
{
/* [over.over] enumerates the places where we can take the address
of an overloaded function, and this is not one of them. */
if (complain & tf_error)
error ("%s cannot resolve address of overloaded function",
implicit ? implicit : "void cast");
else
return error_mark_node;
expr = void_zero_node;
}
else if (implicit && probe == expr && is_overloaded_fn (probe))
{
/* Only warn when there is no &. */
if (complain & tf_warning)
warning (OPT_Waddress, "%s is a reference, not call, to function %qE",
implicit, expr);
if (TREE_CODE (expr) == COMPONENT_REF)
expr = TREE_OPERAND (expr, 0);
}
}
if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr)))
{
if (implicit
&& warn_unused_value
&& !TREE_NO_WARNING (expr)
&& !processing_template_decl)
{
/* The middle end does not warn about expressions that have
been explicitly cast to void, so we must do so here. */
if (!TREE_SIDE_EFFECTS (expr)) {
if (complain & tf_warning)
warning (OPT_Wunused_value, "%s has no effect", implicit);
}
else
{
tree e;
enum tree_code code;
enum tree_code_class tclass;
e = expr;
/* We might like to warn about (say) "(int) f()", as the
cast has no effect, but the compiler itself will
generate implicit conversions under some
circumstances. (For example a block copy will be
turned into a call to "__builtin_memcpy", with a
conversion of the return value to an appropriate
type.) So, to avoid false positives, we strip
conversions. Do not use STRIP_NOPs because it will
not strip conversions to "void", as that is not a
mode-preserving conversion. */
while (TREE_CODE (e) == NOP_EXPR)
e = TREE_OPERAND (e, 0);
code = TREE_CODE (e);
tclass = TREE_CODE_CLASS (code);
if ((tclass == tcc_comparison
|| tclass == tcc_unary
|| (tclass == tcc_binary
&& !(code == MODIFY_EXPR
|| code == INIT_EXPR
|| code == PREDECREMENT_EXPR
|| code == PREINCREMENT_EXPR
|| code == POSTDECREMENT_EXPR
|| code == POSTINCREMENT_EXPR)))
&& (complain & tf_warning))
warning (OPT_Wunused_value, "value computed is not used");
}
}
expr = build1 (CONVERT_EXPR, void_type_node, expr);
}
if (! TREE_SIDE_EFFECTS (expr))
expr = void_zero_node;
return expr;
}
static tree
check_omp_for_incr_expr (location_t loc, tree exp, tree decl)
{
tree t;
if (!INTEGRAL_TYPE_P (TREE_TYPE (exp))
|| TYPE_PRECISION (TREE_TYPE (exp)) < TYPE_PRECISION (TREE_TYPE (decl)))
return error_mark_node;
if (exp == decl)
return build_int_cst (TREE_TYPE (exp), 0);
switch (TREE_CODE (exp))
{
CASE_CONVERT:
t = check_omp_for_incr_expr (loc, TREE_OPERAND (exp, 0), decl);
if (t != error_mark_node)
return fold_convert_loc (loc, TREE_TYPE (exp), t);
break;
case MINUS_EXPR:
t = check_omp_for_incr_expr (loc, TREE_OPERAND (exp, 0), decl);
if (t != error_mark_node)
return fold_build2_loc (loc, MINUS_EXPR,
TREE_TYPE (exp), t, TREE_OPERAND (exp, 1));
break;
case PLUS_EXPR:
t = check_omp_for_incr_expr (loc, TREE_OPERAND (exp, 0), decl);
if (t != error_mark_node)
return fold_build2_loc (loc, PLUS_EXPR,
TREE_TYPE (exp), t, TREE_OPERAND (exp, 1));
t = check_omp_for_incr_expr (loc, TREE_OPERAND (exp, 1), decl);
if (t != error_mark_node)
return fold_build2_loc (loc, PLUS_EXPR,
TREE_TYPE (exp), TREE_OPERAND (exp, 0), t);
break;
case COMPOUND_EXPR:
{
/* cp_build_modify_expr forces preevaluation of the RHS to make
sure that it is evaluated before the lvalue-rvalue conversion
is applied to the LHS. Reconstruct the original expression. */
tree op0 = TREE_OPERAND (exp, 0);
if (TREE_CODE (op0) == TARGET_EXPR
&& !VOID_TYPE_P (TREE_TYPE (op0)))
{
tree op1 = TREE_OPERAND (exp, 1);
tree temp = TARGET_EXPR_SLOT (op0);
if (BINARY_CLASS_P (op1)
&& TREE_OPERAND (op1, 1) == temp)
{
op1 = copy_node (op1);
TREE_OPERAND (op1, 1) = TARGET_EXPR_INITIAL (op0);
return check_omp_for_incr_expr (loc, op1, decl);
}
}
break;
}
default:
break;
}
return error_mark_node;
}
tree
convert_to_void (tree expr, impl_conv_void implicit, tsubst_flags_t complain)
{
if (expr == error_mark_node
|| TREE_TYPE (expr) == error_mark_node)
return error_mark_node;
if (implicit == ICV_CAST)
mark_exp_read (expr);
else
{
tree exprv = expr;
while (TREE_CODE (exprv) == COMPOUND_EXPR)
exprv = TREE_OPERAND (exprv, 1);
if (DECL_P (exprv)
|| handled_component_p (exprv)
|| TREE_CODE (exprv) == INDIRECT_REF)
/* 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))
return error_mark_node;
if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR)
{
if (complain & tf_error)
error ("pseudo-destructor is not called");
return error_mark_node;
}
if (VOID_TYPE_P (TREE_TYPE (expr)))
return expr;
switch (TREE_CODE (expr))
{
case COND_EXPR:
{
/* The two parts of a cond expr might be separate lvalues. */
tree op1 = TREE_OPERAND (expr,1);
tree op2 = TREE_OPERAND (expr,2);
bool side_effects = TREE_SIDE_EFFECTS (op1) || TREE_SIDE_EFFECTS (op2);
tree new_op1, new_op2;
if (implicit != ICV_CAST && !side_effects)
{
new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND, complain);
new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND, complain);
}
else
{
new_op1 = convert_to_void (op1, ICV_CAST, complain);
new_op2 = convert_to_void (op2, ICV_CAST, complain);
}
expr = build3 (COND_EXPR, TREE_TYPE (new_op1),
TREE_OPERAND (expr, 0), new_op1, new_op2);
break;
}
case COMPOUND_EXPR:
{
/* The second part of a compound expr contains the value. */
tree op1 = TREE_OPERAND (expr,1);
tree new_op1;
if (implicit != ICV_CAST && !TREE_NO_WARNING (expr))
new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA, complain);
else
new_op1 = convert_to_void (op1, ICV_CAST, complain);
if (new_op1 != op1)
{
tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1),
TREE_OPERAND (expr, 0), new_op1);
expr = t;
}
break;
}
case NON_LVALUE_EXPR:
case NOP_EXPR:
/* These have already decayed to rvalue. */
break;
case CALL_EXPR: /* We have a special meaning for volatile void fn(). */
break;
case INDIRECT_REF:
{
tree type = TREE_TYPE (expr);
int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0)))
== REFERENCE_TYPE;
int is_volatile = TYPE_VOLATILE (type);
int is_complete = COMPLETE_TYPE_P (complete_type (type));
/* Can't load the value if we don't know the type. */
if (is_volatile && !is_complete)
{
if (complain & tf_warning)
switch (implicit)
{
case ICV_CAST:
warning (0, "conversion to void will not access "
"object of incomplete type %qT", type);
break;
case ICV_SECOND_OF_COND:
warning (0, "indirection will not access object of "
"incomplete type %qT in second operand "
"of conditional expression", type);
break;
case ICV_THIRD_OF_COND:
warning (0, "indirection will not access object of "
"incomplete type %qT in third operand "
"of conditional expression", type);
break;
case ICV_RIGHT_OF_COMMA:
warning (0, "indirection will not access object of "
"incomplete type %qT in right operand of "
"comma operator", type);
break;
case ICV_LEFT_OF_COMMA:
warning (0, "indirection will not access object of "
"incomplete type %qT in left operand of "
"comma operator", type);
break;
case ICV_STATEMENT:
warning (0, "indirection will not access object of "
"incomplete type %qT in statement", type);
break;
case ICV_THIRD_IN_FOR:
warning (0, "indirection will not access object of "
"incomplete type %qT in for increment "
"expression", type);
break;
default:
gcc_unreachable ();
}
}
/* Don't load the value if this is an implicit dereference, or if
the type needs to be handled by ctors/dtors. */
else if (is_volatile && is_reference)
{
if (complain & tf_warning)
switch (implicit)
{
case ICV_CAST:
warning (0, "conversion to void will not access "
"object of type %qT", type);
break;
case ICV_SECOND_OF_COND:
warning (0, "implicit dereference will not access object "
"of type %qT in second operand of "
"conditional expression", type);
break;
case ICV_THIRD_OF_COND:
warning (0, "implicit dereference will not access object "
"of type %qT in third operand of "
"conditional expression", type);
break;
case ICV_RIGHT_OF_COMMA:
warning (0, "implicit dereference will not access object "
"of type %qT in right operand of "
"comma operator", type);
break;
case ICV_LEFT_OF_COMMA:
warning (0, "implicit dereference will not access object "
"of type %qT in left operand of comma operator",
type);
break;
case ICV_STATEMENT:
warning (0, "implicit dereference will not access object "
"of type %qT in statement", type);
break;
case ICV_THIRD_IN_FOR:
warning (0, "implicit dereference will not access object "
"of type %qT in for increment expression",
type);
break;
default:
gcc_unreachable ();
}
}
else if (is_volatile && TREE_ADDRESSABLE (type))
{
if (complain & tf_warning)
switch (implicit)
{
case ICV_CAST:
warning (0, "conversion to void will not access "
"object of non-trivially-copyable type %qT",
type);
break;
case ICV_SECOND_OF_COND:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in second "
"operand of conditional expression", type);
break;
case ICV_THIRD_OF_COND:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in third "
"operand of conditional expression", type);
break;
case ICV_RIGHT_OF_COMMA:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in right "
"operand of comma operator", type);
break;
case ICV_LEFT_OF_COMMA:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in left "
"operand of comma operator", type);
break;
case ICV_STATEMENT:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in statement",
type);
break;
case ICV_THIRD_IN_FOR:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in for "
"increment expression", type);
break;
default:
gcc_unreachable ();
}
}
if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type))
{
/* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF
operation is stripped off. Note that we don't warn about
- an expression with TREE_NO_WARNING set. (For an example of
such expressions, see build_over_call in call.c.)
- automatic dereferencing of references, since the user cannot
control it. (See also warn_if_unused_value() in stmt.c.) */
if (warn_unused_value
&& implicit != ICV_CAST
&& (complain & tf_warning)
&& !TREE_NO_WARNING (expr)
&& !is_reference)
warning (OPT_Wunused_value, "value computed is not used");
expr = TREE_OPERAND (expr, 0);
}
break;
}
case VAR_DECL:
{
/* External variables might be incomplete. */
tree type = TREE_TYPE (expr);
int is_complete = COMPLETE_TYPE_P (complete_type (type));
if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning))
switch (implicit)
{
case ICV_CAST:
warning (0, "conversion to void will not access "
"object %qE of incomplete type %qT", expr, type);
break;
case ICV_SECOND_OF_COND:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in second operand of "
"conditional expression", expr, type);
break;
case ICV_THIRD_OF_COND:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in third operand of "
"conditional expression", expr, type);
break;
case ICV_RIGHT_OF_COMMA:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in right operand of comma operator",
expr, type);
break;
case ICV_LEFT_OF_COMMA:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in left operand of comma operator",
expr, type);
break;
case ICV_STATEMENT:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in statement", expr, type);
break;
case ICV_THIRD_IN_FOR:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in for increment expression",
expr, type);
break;
default:
gcc_unreachable ();
}
break;
}
case TARGET_EXPR:
/* Don't bother with the temporary object returned from a function if
we don't use it and don't need to destroy it. We'll still
allocate space for it in expand_call or declare_return_variable,
but we don't need to track it through all the tree phases. */
if (TARGET_EXPR_IMPLICIT_P (expr)
&& TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr)))
{
tree init = TARGET_EXPR_INITIAL (expr);
if (TREE_CODE (init) == AGGR_INIT_EXPR
&& !AGGR_INIT_VIA_CTOR_P (init))
{
tree fn = AGGR_INIT_EXPR_FN (init);
expr = build_call_array_loc (input_location,
TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))),
fn,
aggr_init_expr_nargs (init),
AGGR_INIT_EXPR_ARGP (init));
}
}
break;
default:;
}
expr = resolve_nondeduced_context (expr);
{
tree probe = expr;
if (TREE_CODE (probe) == ADDR_EXPR)
probe = TREE_OPERAND (expr, 0);
if (type_unknown_p (probe))
{
/* [over.over] enumerates the places where we can take the address
of an overloaded function, and this is not one of them. */
if (complain & tf_error)
switch (implicit)
{
case ICV_CAST:
error ("conversion to void "
"cannot resolve address of overloaded function");
break;
case ICV_SECOND_OF_COND:
error ("second operand of conditional expression "
"cannot resolve address of overloaded function");
break;
case ICV_THIRD_OF_COND:
error ("third operand of conditional expression "
"cannot resolve address of overloaded function");
break;
case ICV_RIGHT_OF_COMMA:
error ("right operand of comma operator "
"cannot resolve address of overloaded function");
break;
case ICV_LEFT_OF_COMMA:
error ("left operand of comma operator "
"cannot resolve address of overloaded function");
break;
case ICV_STATEMENT:
error ("statement "
"cannot resolve address of overloaded function");
break;
case ICV_THIRD_IN_FOR:
error ("for increment expression "
"cannot resolve address of overloaded function");
break;
}
else
return error_mark_node;
expr = void_zero_node;
}
else if (implicit != ICV_CAST && probe == expr && is_overloaded_fn (probe))
{
/* Only warn when there is no &. */
if (complain & tf_warning)
switch (implicit)
{
case ICV_SECOND_OF_COND:
warning (OPT_Waddress,
"second operand of conditional expression "
"is a reference, not call, to function %qE", expr);
break;
case ICV_THIRD_OF_COND:
warning (OPT_Waddress,
"third operand of conditional expression "
"is a reference, not call, to function %qE", expr);
break;
case ICV_RIGHT_OF_COMMA:
warning (OPT_Waddress,
"right operand of comma operator "
"is a reference, not call, to function %qE", expr);
break;
case ICV_LEFT_OF_COMMA:
warning (OPT_Waddress,
"left operand of comma operator "
"is a reference, not call, to function %qE", expr);
break;
case ICV_STATEMENT:
warning (OPT_Waddress,
"statement is a reference, not call, to function %qE",
expr);
break;
case ICV_THIRD_IN_FOR:
warning (OPT_Waddress,
"for increment expression "
"is a reference, not call, to function %qE", expr);
break;
default:
gcc_unreachable ();
}
if (TREE_CODE (expr) == COMPONENT_REF)
expr = TREE_OPERAND (expr, 0);
}
}
if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr)))
{
if (implicit != ICV_CAST
&& warn_unused_value
&& !TREE_NO_WARNING (expr)
&& !processing_template_decl)
{
/* The middle end does not warn about expressions that have
been explicitly cast to void, so we must do so here. */
if (!TREE_SIDE_EFFECTS (expr)) {
if (complain & tf_warning)
switch (implicit)
{
case ICV_SECOND_OF_COND:
warning (OPT_Wunused_value,
"second operand of conditional expression has no effect");
break;
case ICV_THIRD_OF_COND:
warning (OPT_Wunused_value,
"third operand of conditional expression has no effect");
break;
case ICV_RIGHT_OF_COMMA:
warning (OPT_Wunused_value,
"right operand of comma operator has no effect");
break;
case ICV_LEFT_OF_COMMA:
warning (OPT_Wunused_value,
"left operand of comma operator has no effect");
break;
case ICV_STATEMENT:
warning (OPT_Wunused_value,
"statement has no effect");
break;
case ICV_THIRD_IN_FOR:
warning (OPT_Wunused_value,
"for increment expression has no effect");
break;
default:
gcc_unreachable ();
}
}
else
{
tree e;
enum tree_code code;
enum tree_code_class tclass;
e = expr;
/* We might like to warn about (say) "(int) f()", as the
cast has no effect, but the compiler itself will
generate implicit conversions under some
circumstances. (For example a block copy will be
turned into a call to "__builtin_memcpy", with a
conversion of the return value to an appropriate
type.) So, to avoid false positives, we strip
conversions. Do not use STRIP_NOPs because it will
not strip conversions to "void", as that is not a
mode-preserving conversion. */
while (TREE_CODE (e) == NOP_EXPR)
e = TREE_OPERAND (e, 0);
code = TREE_CODE (e);
tclass = TREE_CODE_CLASS (code);
if ((tclass == tcc_comparison
|| tclass == tcc_unary
|| (tclass == tcc_binary
&& !(code == MODIFY_EXPR
|| code == INIT_EXPR
|| code == PREDECREMENT_EXPR
|| code == PREINCREMENT_EXPR
|| code == POSTDECREMENT_EXPR
|| code == POSTINCREMENT_EXPR)))
&& (complain & tf_warning))
warning (OPT_Wunused_value, "value computed is not used");
}
}
expr = build1 (CONVERT_EXPR, void_type_node, expr);
}
if (! TREE_SIDE_EFFECTS (expr))
expr = void_zero_node;
return expr;
}