diff options
author | Joseph Myers <joseph@codesourcery.com> | 2009-03-29 19:13:43 +0100 |
---|---|---|
committer | Joseph Myers <jsm28@gcc.gnu.org> | 2009-03-29 19:13:43 +0100 |
commit | 928c19bbb001967c7ab83a9f856c740680b6661f (patch) | |
tree | a06c7550ad4d8d100141b10b1c0d61bf7548b888 /gcc/doc | |
parent | 5babbcc0fceb0aa66547feb61124ff548929cbfc (diff) | |
download | gcc-928c19bbb001967c7ab83a9f856c740680b6661f.zip gcc-928c19bbb001967c7ab83a9f856c740680b6661f.tar.gz gcc-928c19bbb001967c7ab83a9f856c740680b6661f.tar.bz2 |
re PR c/456 (constant expressions constraints (gcc.dg/c90-const-expr-1))
PR c/456
PR c/5675
PR c/19976
PR c/29116
PR c/31871
PR c/35198
fixincludes:
* inclhack.def (glibc_tgmath): New fix.
* fixincl.x: Regenerate.
* tests/base/tgmath.h: New.
gcc:
* builtins.c (fold_builtin_sincos): Build COMPOUND_EXPR in
void_type_node.
(fold_call_expr): Return a NOP_EXPR from folding rather than the
contained expression.
* c-common.c (c_fully_fold, c_fully_fold_internal, c_save_expr):
New.
(c_common_truthvalue_conversion): Use c_save_expr. Do not fold
conditional expressions for C.
(decl_constant_value_for_optimization): Move from
decl_constant_value_for_broken_optimization in c-typeck.c. Check
whether optimizing and that the expression is a VAR_DECL not of
array type instead of doing such checks in the caller. Do not
check pedantic. Call gcc_unreachable for C++.
* c-common.def (C_MAYBE_CONST_EXPR): New.
* c-common.h (c_fully_fold, c_save_expr,
decl_constant_value_for_optimization): New prototypes.
(C_MAYBE_CONST_EXPR_PRE, C_MAYBE_CONST_EXPR_EXPR,
C_MAYBE_CONST_EXPR_INT_OPERANDS, C_MAYBE_CONST_EXPR_NON_CONST,
EXPR_INT_CONST_OPERANDS): Define.
* c-convert.c (convert): Strip nops from expression.
* c-decl.c (groktypename): Take extra parameters expr and
expr_const_operands. Update call to grokdeclarator.
(start_decl): Update call to grokdeclarator. Add statement for
expressions used in type of decl.
(grokparm): Update call to grokdeclarator.
(push_parm_decl): Update call to grokdeclarator.
(build_compound_literal): Add parameter non_const and build a
C_MAYBE_COSNT_EXPR if applicable.
(grokdeclarator): Take extra parameters expr and
expr_const_operands. Track expressions used in declaration
specifiers and declarators. Fold array sizes and track whether
they are constant expressions and whether they are integer
constant expressions.
(parser_xref_tag): Set expr and expr_const_operands fields in
return value.
(grokfield): Update call to grokdeclarator.
(start_function): Update call to grokdeclarator.
(build_null_declspecs): Set expr and expr_const_operands fields in
return value.
(declspecs_add_type): Handle expressions in typeof specifiers.
* c-parser.c (c_parser_declspecs): Set expr and
expr_const_operands fields for declaration specifiers.
(c_parser_enum_specifier): Likewise.
(c_parser_struct_or_union_specifier): Likewise.
(c_parser_typeof_specifier): Likewise. Update call to
groktypename. Fold expression as needed. Return expressions with
type instead of adding statements.
(c_parser_attributes): Update calls to c_parser_expr_list.
(c_parser_statement_after_labels): Fold expression before passing
to objc_build_throw_stmt.
(c_parser_condition): Fold expression.
(c_parser_asm_operands): Fold expression.
(c_parser_conditional_expression): Use c_save_expr. Update call
to build_conditional_expr.
(c_parser_alignof_expression): Update call to groktypename.
(c_parser_postfix_expression): Preserve C_MAYBE_CONST_EXPR as
original_code. Fold expression argument of va_arg. Create
C_MAYBE_CONST_EXPR to preserve side effects of expressions in type
argument to va_arg. Update calls to groktypename. Fold array
index for offsetof. Verify that first argument to
__builtin_choose_expr has integer type.
(c_parser_postfix_expression_after_paren_type): Update calls to
groktypename and build_compound_literal. Handle expressions with
side effects in type name.
(c_parser_postfix_expression_after_primary): Update call to
c_parser_expr_list. Set original_code for calls to
__builtin_constant_p.
(c_parser_expr_list): Take extra parameter fold_p. Fold
expressions if requested.
(c_parser_objc_type_name): Update call to groktypename.
(c_parser_objc_synchronized_statement): Fold expression.
(c_parser_objc_receiver): Fold expression.
(c_parser_objc_keywordexpr): Update call to c_parser_expr_list.
(c_parser_omp_clause_num_threads, c_parser_omp_clause_schedule,
c_parser_omp_atomic, c_parser_omp_for_loop): Fold expressions.
* c-tree.h (CONSTRUCTOR_NON_CONST): Define.
(struct c_typespec): Add elements expr and expr_const_operands.
(struct c_declspecs): Add elements expr and expr_const_operands.
(groktypename, build_conditional_expr, build_compound_literal):
Update prototypes.
(in_late_binary_op): Declare.
* c-typeck.c (note_integer_operands): New function.
(in_late_binary_op): New variable.
(decl_constant_value_for_broken_optimization): Move to c-common.c
and rename to decl_constant_value_for_optimization.
(default_function_array_conversion): Do not strip nops.
(default_conversion): Do not call
decl_constant_value_for_broken_optimization.
(build_array_ref): Do not fold result.
(c_expr_sizeof_expr): Fold operand. Use C_MAYBE_CONST_EXPR for
result when operand is a VLA.
(c_expr_sizeof_type): Update call to groktypename. Handle
expressions included in type name. Use C_MAYBE_CONST_EXPR for
result when operand names a VLA type.
(build_function_call): Update call to build_compound_literal.
Only fold result for calls to __builtin_* functions. Strip
NOP_EXPR from INTEGER_CST returned from such functions. Fold
the function designator.
(convert_arguments): Fold arguments. Update call to
convert_for_assignment.
(build_unary_op): Handle increment and decrement of
C_MAYBE_CONST_EXPR. Move lvalue checks for increment and
decrement earlier. Fold operand of increment and decrement.
Handle address of C_MAYBE_CONST_EXPR. Only fold expression being
built for integer operand. Wrap returns that are INTEGER_CSTs
without being integer constant expressions or that have integer
constant operands without being INTEGER_CSTs.
(lvalue_p): Handle C_MAYBE_CONST_EXPR.
(build_conditional_expr): Add operand ifexp_bcp. Track whether
result is an integer constant expression or can be used in
unevaluated parts of one and avoid folding and wrap as
appropriate. Fold operands before possibly doing -Wsign-compare
warnings.
(build_compound_expr): Wrap result for C99 if operands can be used
in integer constant expressions.
(build_c_cast): Update call to digest_init. Do not ignore
overflow from casting floating-point constants to integers. Wrap
results that could be confused with integer constant expressions,
null pointer constants or floating-point constants.
(c_cast_expr): Update call to groktypename. Handle expressions
included in type name.
(build_modify_expr): Handle modifying a C_MAYBE_CONST_EXPR. Fold
lhs inside possible SAVE_EXPR. Fold RHS before assignment.
Update calls to convert_for_assignment.
(convert_for_assignment): Take new parameter
null_pointer_constant. Do not strip nops or call
decl_constant_value_for_broken_optimization. Set
in_late_binary_op for conversions to boolean.
(store_init_value): Update call to digest_init.
(digest_init): Take new parameter null_pointer_constant. Do not
call decl_constant_value_for_broken_optimization. pedwarn for
initializers not constant expressions. Update calls to
convert_for_assignment.
(constructor_nonconst): New.
(struct constructor_stack): Add nonconst element.
(really_start_incremental_init, push_init_level, pop_init_level):
Handle constructor_nonconst and nonconst element.
(set_init_index): Call constant_expression_warning for array
designators.
(output_init_element): Fold value. Set constructor_nonconst as
applicable. pedwarn for initializers not constant expressions.
Update call to digest_init. Call constant_expression_warning
where constant initializers are required.
(process_init_element): Use c_save_expr.
(c_finish_goto_ptr): Fold expression.
(c_finish_return): Fold return value. Update call to
convert_for_assignment.
(c_start_case): Fold switch expression.
(c_process_expr_stmt): Fold expression.
(c_finish_stmt_expr): Create C_MAYBE_CONST_EXPR as needed to
ensure statement expression is not evaluated in constant
expression.
(build_binary_op): Track whether results are integer constant
expressions or may occur in such, disable folding and wrap results
as applicable. Fold operands for -Wsign-compare warnings unless
in_late_binary_op.
(c_objc_common_truthvalue_conversion): Handle results folded to
integer constants that are not integer constant expressions.
* doc/extend.texi: Document when typeof operands are evaluated,
that condition of __builtin_choose_expr is an integer constant
expression, and more about use of __builtin_constant_p in
initializers.
gcc/objc:
* objc-act.c (objc_finish_try_stmt): Set in_late_binary_op.
gcc/testsuite:
* gcc.c-torture/compile/20081108-1.c,
gcc.c-torture/compile/20081108-2.c,
gcc.c-torture/compile/20081108-3.c, gcc.dg/bconstp-2.c,
gcc.dg/bconstp-3.c, gcc.dg/bconstp-4.c, gcc.dg/c90-const-expr-6.c,
gcc.dg/c90-const-expr-7.c, gcc.dg/c90-const-expr-8.c,
gcc.dg/c90-const-expr-9.c, gcc.dg/c90-const-expr-10.c,
gcc.dg/c90-const-expr-11.c, gcc.dg/c99-const-expr-6.c,
gcc.dg/c99-const-expr-7.c, gcc.dg/c99-const-expr-8.c,
gcc.dg/c99-const-expr-9.c, gcc.dg/c99-const-expr-10.c,
gcc.dg/c99-const-expr-11.c, gcc.dg/c99-const-expr-12.c,
gcc.dg/c99-const-expr-13.c, gcc.dg/compare10.c,
gcc.dg/gnu89-const-expr-1.c, gcc.dg/gnu89-const-expr-2.c,
gcc.dg/gnu99-const-expr-1.c, gcc.dg/gnu99-const-expr-2.c,
gcc.dg/gnu99-const-expr-3.c, gcc.dg/vla-12.c, gcc.dg/vla-13.c,
gcc.dg/vla-14.c, gcc.dg/vla-15.c, gcc.dg/vla-16.c: New tests.
* gcc.dg/c90-const-expr-1.c, gcc.dg/c90-const-expr-2.c,
gcc.dg/c90-const-expr-3.c, gcc.dg/c99-const-expr-2.c,
gcc.dg/c99-const-expr-3.c, gcc.dg/c99-static-1.c: Remove XFAILs.
* gcc.dg/c90-const-expr-2.c: Use ZERO in place of 0 in another
case.
* gcc.dg/overflow-warn-1.c, gcc.dg/overflow-warn-2.c,
gcc.dg/overflow-warn-3.c, gcc.dg/overflow-warn-4.c: Remove
XFAILs. Update expected messages.
* gcc.dg/pr14649-1.c, gcc.dg/pr19984.c, gcc.dg/pr25682.c: Update
expected messages.
* gcc.dg/real-const-1.c: Replace with test from original PR.
* gcc.dg/vect/pr32230.c: Use intermediate cast to __PTRDIFF_TYPE__
when casting from non-constant integer to pointer.
From-SVN: r145254
Diffstat (limited to 'gcc/doc')
-rw-r--r-- | gcc/doc/extend.texi | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 0e9d739..9500feb 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -663,6 +663,10 @@ A @code{typeof}-construct can be used anywhere a typedef name could be used. For example, you can use it in a declaration, in a cast, or inside of @code{sizeof} or @code{typeof}. +The operand of @code{typeof} is evaluated for its side effects if and +only if it is an expression of variably modified type or the name of +such a type. + @code{typeof} is often useful in conjunction with the statements-within-expressions feature. Here is how the two together can be used to define a safe ``maximum'' macro that operates on any @@ -6635,9 +6639,8 @@ depending on the arguments' types. For example: You can use the built-in function @code{__builtin_choose_expr} to evaluate code depending on the value of a constant expression. This -built-in function returns @var{exp1} if @var{const_exp}, which is a -constant expression that must be able to be determined at compile time, -is nonzero. Otherwise it returns 0. +built-in function returns @var{exp1} if @var{const_exp}, which is an +integer constant expression, is nonzero. Otherwise it returns 0. This built-in function is analogous to the @samp{? :} operator in C, except that the expression returned has its type unaltered by promotion @@ -6716,7 +6719,11 @@ static const int table[] = @{ @noindent This is an acceptable initializer even if @var{EXPRESSION} is not a -constant expression. GCC must be more conservative about evaluating the +constant expression, including the case where +@code{__builtin_constant_p} returns 1 because @var{EXPRESSION} can be +folded to a constant but @var{EXPRESSION} contains operands that would +not otherwize be permitted in a static initializer (for example, +@code{0 && foo ()}). GCC must be more conservative about evaluating the built-in in this case, because it has no opportunity to perform optimization. |