gcc/c-common.c

/* Subroutines shared by all languages that are variants of C.
   Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
   2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
   Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "intl.h"
#include "tree.h"
#include "flags.h"
#include "output.h"
#include "c-pragma.h"
#include "rtl.h"
#include "ggc.h"
#include "varray.h"
#include "expr.h"
#include "c-common.h"
#include "diagnostic.h"
#include "tm_p.h"
#include "obstack.h"
#include "cpplib.h"
#include "target.h"
#include "langhooks.h"
#include "tree-inline.h"
#include "c-tree.h"
#include "toplev.h"
#include "tree-iterator.h"
#include "hashtab.h"
#include "tree-mudflap.h"
#include "opts.h"
#include "real.h"
#include "cgraph.h"
#include "target-def.h"
#include "gimple.h"
#include "fixed-value.h"
#include "libfuncs.h"

cpp_reader *parse_in;		/* Declared in c-pragma.h.  */

/* We let tm.h override the types used here, to handle trivial differences
   such as the choice of unsigned int or long unsigned int for size_t.
   When machines start needing nontrivial differences in the size type,
   it would be best to do something here to figure out automatically
   from other information what type to use.  */

#ifndef SIZE_TYPE
#define SIZE_TYPE "long unsigned int"
#endif

#ifndef PID_TYPE
#define PID_TYPE "int"
#endif

#ifndef CHAR16_TYPE
#define CHAR16_TYPE "short unsigned int"
#endif

#ifndef CHAR32_TYPE
#define CHAR32_TYPE "unsigned int"
#endif

#ifndef WCHAR_TYPE
#define WCHAR_TYPE "int"
#endif

/* WCHAR_TYPE gets overridden by -fshort-wchar.  */
#define MODIFIED_WCHAR_TYPE \
	(flag_short_wchar ? "short unsigned int" : WCHAR_TYPE)

#ifndef PTRDIFF_TYPE
#define PTRDIFF_TYPE "long int"
#endif

#ifndef WINT_TYPE
#define WINT_TYPE "unsigned int"
#endif

#ifndef INTMAX_TYPE
#define INTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)	\
		     ? "int"					\
		     : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE)	\
			? "long int"				\
			: "long long int"))
#endif

#ifndef UINTMAX_TYPE
#define UINTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)	\
		     ? "unsigned int"				\
		     : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE)	\
			? "long unsigned int"			\
			: "long long unsigned int"))
#endif

/* The following symbols are subsumed in the c_global_trees array, and
   listed here individually for documentation purposes.

   INTEGER_TYPE and REAL_TYPE nodes for the standard data types.

	tree short_integer_type_node;
	tree long_integer_type_node;
	tree long_long_integer_type_node;

	tree short_unsigned_type_node;
	tree long_unsigned_type_node;
	tree long_long_unsigned_type_node;

	tree truthvalue_type_node;
	tree truthvalue_false_node;
	tree truthvalue_true_node;

	tree ptrdiff_type_node;

	tree unsigned_char_type_node;
	tree signed_char_type_node;
	tree wchar_type_node;
	tree signed_wchar_type_node;
	tree unsigned_wchar_type_node;

	tree char16_type_node;
	tree char32_type_node;

	tree float_type_node;
	tree double_type_node;
	tree long_double_type_node;

	tree complex_integer_type_node;
	tree complex_float_type_node;
	tree complex_double_type_node;
	tree complex_long_double_type_node;

	tree dfloat32_type_node;
	tree dfloat64_type_node;
	tree_dfloat128_type_node;

	tree intQI_type_node;
	tree intHI_type_node;
	tree intSI_type_node;
	tree intDI_type_node;
	tree intTI_type_node;

	tree unsigned_intQI_type_node;
	tree unsigned_intHI_type_node;
	tree unsigned_intSI_type_node;
	tree unsigned_intDI_type_node;
	tree unsigned_intTI_type_node;

	tree widest_integer_literal_type_node;
	tree widest_unsigned_literal_type_node;

   Nodes for types `void *' and `const void *'.

	tree ptr_type_node, const_ptr_type_node;

   Nodes for types `char *' and `const char *'.

	tree string_type_node, const_string_type_node;

   Type `char[SOMENUMBER]'.
   Used when an array of char is needed and the size is irrelevant.

	tree char_array_type_node;

   Type `int[SOMENUMBER]' or something like it.
   Used when an array of int needed and the size is irrelevant.

	tree int_array_type_node;

   Type `wchar_t[SOMENUMBER]' or something like it.
   Used when a wide string literal is created.

	tree wchar_array_type_node;

   Type `char16_t[SOMENUMBER]' or something like it.
   Used when a UTF-16 string literal is created.

	tree char16_array_type_node;

   Type `char32_t[SOMENUMBER]' or something like it.
   Used when a UTF-32 string literal is created.

	tree char32_array_type_node;

   Type `int ()' -- used for implicit declaration of functions.

	tree default_function_type;

   A VOID_TYPE node, packaged in a TREE_LIST.

	tree void_list_node;

  The lazily created VAR_DECLs for __FUNCTION__, __PRETTY_FUNCTION__,
  and __func__. (C doesn't generate __FUNCTION__ and__PRETTY_FUNCTION__
  VAR_DECLS, but C++ does.)

	tree function_name_decl_node;
	tree pretty_function_name_decl_node;
	tree c99_function_name_decl_node;

  Stack of nested function name VAR_DECLs.

	tree saved_function_name_decls;

*/

tree c_global_trees[CTI_MAX];

/* Switches common to the C front ends.  */

/* Nonzero if preprocessing only.  */

int flag_preprocess_only;

/* Nonzero means don't output line number information.  */

char flag_no_line_commands;

/* Nonzero causes -E output not to be done, but directives such as
   #define that have side effects are still obeyed.  */

char flag_no_output;

/* Nonzero means dump macros in some fashion.  */

char flag_dump_macros;

/* Nonzero means pass #include lines through to the output.  */

char flag_dump_includes;

/* Nonzero means process PCH files while preprocessing.  */

bool flag_pch_preprocess;

/* The file name to which we should write a precompiled header, or
   NULL if no header will be written in this compile.  */

const char *pch_file;

/* Nonzero if an ISO standard was selected.  It rejects macros in the
   user's namespace.  */
int flag_iso;

/* Nonzero if -undef was given.  It suppresses target built-in macros
   and assertions.  */
int flag_undef;

/* Nonzero means don't recognize the non-ANSI builtin functions.  */

int flag_no_builtin;

/* Nonzero means don't recognize the non-ANSI builtin functions.
   -ansi sets this.  */

int flag_no_nonansi_builtin;

/* Nonzero means give `double' the same size as `float'.  */

int flag_short_double;

/* Nonzero means give `wchar_t' the same size as `short'.  */

int flag_short_wchar;

/* Nonzero means allow implicit conversions between vectors with
   differing numbers of subparts and/or differing element types.  */
int flag_lax_vector_conversions;

/* Nonzero means allow Microsoft extensions without warnings or errors.  */
int flag_ms_extensions;

/* Nonzero means don't recognize the keyword `asm'.  */

int flag_no_asm;

/* Nonzero means to treat bitfields as signed unless they say `unsigned'.  */

int flag_signed_bitfields = 1;

/* Warn about #pragma directives that are not recognized.  */

int warn_unknown_pragmas; /* Tri state variable.  */

/* Warn about format/argument anomalies in calls to formatted I/O functions
   (*printf, *scanf, strftime, strfmon, etc.).  */

int warn_format;

/* Warn about using __null (as NULL in C++) as sentinel.  For code compiled
   with GCC this doesn't matter as __null is guaranteed to have the right
   size.  */

int warn_strict_null_sentinel;

/* Zero means that faster, ...NonNil variants of objc_msgSend...
   calls will be used in ObjC; passing nil receivers to such calls
   will most likely result in crashes.  */
int flag_nil_receivers = 1;

/* Nonzero means that code generation will be altered to support
   "zero-link" execution.  This currently affects ObjC only, but may
   affect other languages in the future.  */
int flag_zero_link = 0;

/* Nonzero means emit an '__OBJC, __image_info' for the current translation
   unit.  It will inform the ObjC runtime that class definition(s) herein
   contained are to replace one(s) previously loaded.  */
int flag_replace_objc_classes = 0;

/* C/ObjC language option variables.  */


/* Nonzero means allow type mismatches in conditional expressions;
   just make their values `void'.  */

int flag_cond_mismatch;

/* Nonzero means enable C89 Amendment 1 features.  */

int flag_isoc94;

/* Nonzero means use the ISO C99 dialect of C.  */

int flag_isoc99;

/* Nonzero means that we have builtin functions, and main is an int.  */

int flag_hosted = 1;


/* ObjC language option variables.  */


/* Open and close the file for outputting class declarations, if
   requested (ObjC).  */

int flag_gen_declaration;

/* Tells the compiler that this is a special run.  Do not perform any
   compiling, instead we are to test some platform dependent features
   and output a C header file with appropriate definitions.  */

int print_struct_values;

/* Tells the compiler what is the constant string class for ObjC.  */

const char *constant_string_class_name;


/* C++ language option variables.  */


/* Nonzero means don't recognize any extension keywords.  */

int flag_no_gnu_keywords;

/* Nonzero means do emit exported implementations of functions even if
   they can be inlined.  */

int flag_implement_inlines = 1;

/* Nonzero means that implicit instantiations will be emitted if needed.  */

int flag_implicit_templates = 1;

/* Nonzero means that implicit instantiations of inline templates will be
   emitted if needed, even if instantiations of non-inline templates
   aren't.  */

int flag_implicit_inline_templates = 1;

/* Nonzero means generate separate instantiation control files and
   juggle them at link time.  */

int flag_use_repository;

/* Nonzero if we want to issue diagnostics that the standard says are not
   required.  */

int flag_optional_diags = 1;

/* Nonzero means we should attempt to elide constructors when possible.  */

int flag_elide_constructors = 1;

/* Nonzero means that member functions defined in class scope are
   inline by default.  */

int flag_default_inline = 1;

/* Controls whether compiler generates 'type descriptor' that give
   run-time type information.  */

int flag_rtti = 1;

/* Nonzero if we want to conserve space in the .o files.  We do this
   by putting uninitialized data and runtime initialized data into
   .common instead of .data at the expense of not flagging multiple
   definitions.  */

int flag_conserve_space;

/* Nonzero if we want to obey access control semantics.  */

int flag_access_control = 1;

/* Nonzero if we want to check the return value of new and avoid calling
   constructors if it is a null pointer.  */

int flag_check_new;

/* The C++ dialect being used. C++98 is the default.  */

enum cxx_dialect cxx_dialect = cxx98;

/* Nonzero if we want the new ISO rules for pushing a new scope for `for'
   initialization variables.
   0: Old rules, set by -fno-for-scope.
   2: New ISO rules, set by -ffor-scope.
   1: Try to implement new ISO rules, but with backup compatibility
   (and warnings).  This is the default, for now.  */

int flag_new_for_scope = 1;

/* Nonzero if we want to emit defined symbols with common-like linkage as
   weak symbols where possible, in order to conform to C++ semantics.
   Otherwise, emit them as local symbols.  */

int flag_weak = 1;

/* 0 means we want the preprocessor to not emit line directives for
   the current working directory.  1 means we want it to do it.  -1
   means we should decide depending on whether debugging information
   is being emitted or not.  */

int flag_working_directory = -1;

/* Nonzero to use __cxa_atexit, rather than atexit, to register
   destructors for local statics and global objects.  '2' means it has been
   set nonzero as a default, not by a command-line flag.  */

int flag_use_cxa_atexit = DEFAULT_USE_CXA_ATEXIT;

/* Nonzero to use __cxa_get_exception_ptr in C++ exception-handling
   code.  '2' means it has not been set explicitly on the command line.  */

int flag_use_cxa_get_exception_ptr = 2;

/* Nonzero means to implement standard semantics for exception
   specifications, calling unexpected if an exception is thrown that
   doesn't match the specification.  Zero means to treat them as
   assertions and optimize accordingly, but not check them.  */

int flag_enforce_eh_specs = 1;

/* Nonzero means to generate thread-safe code for initializing local
   statics.  */

int flag_threadsafe_statics = 1;

/* Nonzero means warn about implicit declarations.  */

int warn_implicit = 1;

/* Maximum template instantiation depth.  This limit is rather
   arbitrary, but it exists to limit the time it takes to notice
   infinite template instantiations.  */

int max_tinst_depth = 500;



/* The elements of `ridpointers' are identifier nodes for the reserved
   type names and storage classes.  It is indexed by a RID_... value.  */
tree *ridpointers;

tree (*make_fname_decl) (tree, int);

/* Nonzero means the expression being parsed will never be evaluated.
   This is a count, since unevaluated expressions can nest.  */
int skip_evaluation;

/* Information about how a function name is generated.  */
struct fname_var_t
{
  tree *const decl;	/* pointer to the VAR_DECL.  */
  const unsigned rid;	/* RID number for the identifier.  */
  const int pretty;	/* How pretty is it? */
};

/* The three ways of getting then name of the current function.  */

const struct fname_var_t fname_vars[] =
{
  /* C99 compliant __func__, must be first.  */
  {&c99_function_name_decl_node, RID_C99_FUNCTION_NAME, 0},
  /* GCC __FUNCTION__ compliant.  */
  {&function_name_decl_node, RID_FUNCTION_NAME, 0},
  /* GCC __PRETTY_FUNCTION__ compliant.  */
  {&pretty_function_name_decl_node, RID_PRETTY_FUNCTION_NAME, 1},
  {NULL, 0, 0},
};

static tree check_case_value (tree);
static bool check_case_bounds (tree, tree, tree *, tree *);

static tree handle_packed_attribute (tree *, tree, tree, int, bool *);
static tree handle_nocommon_attribute (tree *, tree, tree, int, bool *);
static tree handle_common_attribute (tree *, tree, tree, int, bool *);
static tree handle_noreturn_attribute (tree *, tree, tree, int, bool *);
static tree handle_hot_attribute (tree *, tree, tree, int, bool *);
static tree handle_cold_attribute (tree *, tree, tree, int, bool *);
static tree handle_noinline_attribute (tree *, tree, tree, int, bool *);
static tree handle_always_inline_attribute (tree *, tree, tree, int,
					    bool *);
static tree handle_gnu_inline_attribute (tree *, tree, tree, int, bool *);
static tree handle_artificial_attribute (tree *, tree, tree, int, bool *);
static tree handle_flatten_attribute (tree *, tree, tree, int, bool *);
static tree handle_error_attribute (tree *, tree, tree, int, bool *);
static tree handle_used_attribute (tree *, tree, tree, int, bool *);
static tree handle_unused_attribute (tree *, tree, tree, int, bool *);
static tree handle_externally_visible_attribute (tree *, tree, tree, int,
						 bool *);
static tree handle_const_attribute (tree *, tree, tree, int, bool *);
static tree handle_transparent_union_attribute (tree *, tree, tree,
						int, bool *);
static tree handle_constructor_attribute (tree *, tree, tree, int, bool *);
static tree handle_destructor_attribute (tree *, tree, tree, int, bool *);
static tree handle_mode_attribute (tree *, tree, tree, int, bool *);
static tree handle_section_attribute (tree *, tree, tree, int, bool *);
static tree handle_aligned_attribute (tree *, tree, tree, int, bool *);
static tree handle_weak_attribute (tree *, tree, tree, int, bool *) ;
static tree handle_alias_attribute (tree *, tree, tree, int, bool *);
static tree handle_weakref_attribute (tree *, tree, tree, int, bool *) ;
static tree handle_visibility_attribute (tree *, tree, tree, int,
					 bool *);
static tree handle_tls_model_attribute (tree *, tree, tree, int,
					bool *);
static tree handle_no_instrument_function_attribute (tree *, tree,
						     tree, int, bool *);
static tree handle_malloc_attribute (tree *, tree, tree, int, bool *);
static tree handle_returns_twice_attribute (tree *, tree, tree, int, bool *);
static tree handle_no_limit_stack_attribute (tree *, tree, tree, int,
					     bool *);
static tree handle_pure_attribute (tree *, tree, tree, int, bool *);
static tree handle_novops_attribute (tree *, tree, tree, int, bool *);
static tree handle_deprecated_attribute (tree *, tree, tree, int,
					 bool *);
static tree handle_vector_size_attribute (tree *, tree, tree, int,
					  bool *);
static tree handle_nonnull_attribute (tree *, tree, tree, int, bool *);
static tree handle_nothrow_attribute (tree *, tree, tree, int, bool *);
static tree handle_cleanup_attribute (tree *, tree, tree, int, bool *);
static tree handle_warn_unused_result_attribute (tree *, tree, tree, int,
						 bool *);
static tree handle_sentinel_attribute (tree *, tree, tree, int, bool *);
static tree handle_type_generic_attribute (tree *, tree, tree, int, bool *);
static tree handle_alloc_size_attribute (tree *, tree, tree, int, bool *);
static tree handle_target_attribute (tree *, tree, tree, int, bool *);
static tree handle_optimize_attribute (tree *, tree, tree, int, bool *);

static void check_function_nonnull (tree, int, tree *);
static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);
static bool get_nonnull_operand (tree, unsigned HOST_WIDE_INT *);
static int resort_field_decl_cmp (const void *, const void *);

/* Reserved words.  The third field is a mask: keywords are disabled
   if they match the mask.

   Masks for languages:
   C --std=c89: D_C99 | D_CXXONLY | D_OBJC | D_CXX_OBJC
   C --std=c99: D_CXXONLY | D_OBJC
   ObjC is like C except that D_OBJC and D_CXX_OBJC are not set
   C++ --std=c98: D_CONLY | D_CXXOX | D_OBJC
   C++ --std=c0x: D_CONLY | D_OBJC
   ObjC++ is like C++ except that D_OBJC is not set

   If -fno-asm is used, D_ASM is added to the mask.  If
   -fno-gnu-keywords is used, D_EXT is added.  If -fno-asm and C in
   C89 mode, D_EXT89 is added for both -fno-asm and -fno-gnu-keywords.
   In C with -Wc++-compat, we warn if D_CXXWARN is set.  */

const struct c_common_resword c_common_reswords[] =
{
  { "_Bool",		RID_BOOL,      D_CONLY },
  { "_Complex",		RID_COMPLEX,	0 },
  { "_Decimal32",       RID_DFLOAT32,  D_CONLY | D_EXT },
  { "_Decimal64",       RID_DFLOAT64,  D_CONLY | D_EXT },
  { "_Decimal128",      RID_DFLOAT128, D_CONLY | D_EXT },
  { "_Fract",           RID_FRACT,     D_CONLY | D_EXT },
  { "_Accum",           RID_ACCUM,     D_CONLY | D_EXT },
  { "_Sat",             RID_SAT,       D_CONLY | D_EXT },
  { "__FUNCTION__",	RID_FUNCTION_NAME, 0 },
  { "__PRETTY_FUNCTION__", RID_PRETTY_FUNCTION_NAME, 0 },
  { "__alignof",	RID_ALIGNOF,	0 },
  { "__alignof__",	RID_ALIGNOF,	0 },
  { "__asm",		RID_ASM,	0 },
  { "__asm__",		RID_ASM,	0 },
  { "__attribute",	RID_ATTRIBUTE,	0 },
  { "__attribute__",	RID_ATTRIBUTE,	0 },
  { "__builtin_choose_expr", RID_CHOOSE_EXPR, D_CONLY },
  { "__builtin_offsetof", RID_OFFSETOF, 0 },
  { "__builtin_types_compatible_p", RID_TYPES_COMPATIBLE_P, D_CONLY },
  { "__builtin_va_arg",	RID_VA_ARG,	0 },
  { "__complex",	RID_COMPLEX,	0 },
  { "__complex__",	RID_COMPLEX,	0 },
  { "__const",		RID_CONST,	0 },
  { "__const__",	RID_CONST,	0 },
  { "__decltype",       RID_DECLTYPE,   D_CXXONLY },
  { "__extension__",	RID_EXTENSION,	0 },
  { "__func__",		RID_C99_FUNCTION_NAME, 0 },
  { "__has_nothrow_assign", RID_HAS_NOTHROW_ASSIGN, D_CXXONLY },
  { "__has_nothrow_constructor", RID_HAS_NOTHROW_CONSTRUCTOR, D_CXXONLY },
  { "__has_nothrow_copy", RID_HAS_NOTHROW_COPY, D_CXXONLY },
  { "__has_trivial_assign", RID_HAS_TRIVIAL_ASSIGN, D_CXXONLY },
  { "__has_trivial_constructor", RID_HAS_TRIVIAL_CONSTRUCTOR, D_CXXONLY },
  { "__has_trivial_copy", RID_HAS_TRIVIAL_COPY, D_CXXONLY },
  { "__has_trivial_destructor", RID_HAS_TRIVIAL_DESTRUCTOR, D_CXXONLY },
  { "__has_virtual_destructor", RID_HAS_VIRTUAL_DESTRUCTOR, D_CXXONLY },
  { "__is_abstract",	RID_IS_ABSTRACT, D_CXXONLY },
  { "__is_base_of",	RID_IS_BASE_OF, D_CXXONLY },
  { "__is_class",	RID_IS_CLASS,	D_CXXONLY },
  { "__is_convertible_to", RID_IS_CONVERTIBLE_TO, D_CXXONLY },
  { "__is_empty",	RID_IS_EMPTY,	D_CXXONLY },
  { "__is_enum",	RID_IS_ENUM,	D_CXXONLY },
  { "__is_pod",		RID_IS_POD,	D_CXXONLY },
  { "__is_polymorphic",	RID_IS_POLYMORPHIC, D_CXXONLY },
  { "__is_union",	RID_IS_UNION,	D_CXXONLY },
  { "__imag",		RID_IMAGPART,	0 },
  { "__imag__",		RID_IMAGPART,	0 },
  { "__inline",		RID_INLINE,	0 },
  { "__inline__",	RID_INLINE,	0 },
  { "__label__",	RID_LABEL,	0 },
  { "__null",		RID_NULL,	0 },
  { "__real",		RID_REALPART,	0 },
  { "__real__",		RID_REALPART,	0 },
  { "__restrict",	RID_RESTRICT,	0 },
  { "__restrict__",	RID_RESTRICT,	0 },
  { "__signed",		RID_SIGNED,	0 },
  { "__signed__",	RID_SIGNED,	0 },
  { "__thread",		RID_THREAD,	0 },
  { "__typeof",		RID_TYPEOF,	0 },
  { "__typeof__",	RID_TYPEOF,	0 },
  { "__volatile",	RID_VOLATILE,	0 },
  { "__volatile__",	RID_VOLATILE,	0 },
  { "asm",		RID_ASM,	D_ASM },
  { "auto",		RID_AUTO,	0 },
  { "bool",		RID_BOOL,	D_CXXONLY | D_CXXWARN },
  { "break",		RID_BREAK,	0 },
  { "case",		RID_CASE,	0 },
  { "catch",		RID_CATCH,	D_CXX_OBJC | D_CXXWARN },
  { "char",		RID_CHAR,	0 },
  { "char16_t",		RID_CHAR16,	D_CXXONLY | D_CXX0X | D_CXXWARN },
  { "char32_t",		RID_CHAR32,	D_CXXONLY | D_CXX0X | D_CXXWARN },
  { "class",		RID_CLASS,	D_CXX_OBJC | D_CXXWARN },
  { "const",		RID_CONST,	0 },
  { "const_cast",	RID_CONSTCAST,	D_CXXONLY | D_CXXWARN },
  { "continue",		RID_CONTINUE,	0 },
  { "decltype",         RID_DECLTYPE,   D_CXXONLY | D_CXX0X | D_CXXWARN },
  { "default",		RID_DEFAULT,	0 },
  { "delete",		RID_DELETE,	D_CXXONLY | D_CXXWARN },
  { "do",		RID_DO,		0 },
  { "double",		RID_DOUBLE,	0 },
  { "dynamic_cast",	RID_DYNCAST,	D_CXXONLY | D_CXXWARN },
  { "else",		RID_ELSE,	0 },
  { "enum",		RID_ENUM,	0 },
  { "explicit",		RID_EXPLICIT,	D_CXXONLY | D_CXXWARN },
  { "export",		RID_EXPORT,	D_CXXONLY | D_CXXWARN },
  { "extern",		RID_EXTERN,	0 },
  { "false",		RID_FALSE,	D_CXXONLY | D_CXXWARN },
  { "float",		RID_FLOAT,	0 },
  { "for",		RID_FOR,	0 },
  { "friend",		RID_FRIEND,	D_CXXONLY | D_CXXWARN },
  { "goto",		RID_GOTO,	0 },
  { "if",		RID_IF,		0 },
  { "inline",		RID_INLINE,	D_EXT89 },
  { "int",		RID_INT,	0 },
  { "long",		RID_LONG,	0 },
  { "mutable",		RID_MUTABLE,	D_CXXONLY | D_CXXWARN },
  { "namespace",	RID_NAMESPACE,	D_CXXONLY | D_CXXWARN },
  { "new",		RID_NEW,	D_CXXONLY | D_CXXWARN },
  { "operator",		RID_OPERATOR,	D_CXXONLY | D_CXXWARN },
  { "private",		RID_PRIVATE,	D_CXX_OBJC | D_CXXWARN },
  { "protected",	RID_PROTECTED,	D_CXX_OBJC | D_CXXWARN },
  { "public",		RID_PUBLIC,	D_CXX_OBJC | D_CXXWARN },
  { "register",		RID_REGISTER,	0 },
  { "reinterpret_cast",	RID_REINTCAST,	D_CXXONLY | D_CXXWARN },
  { "restrict",		RID_RESTRICT,	D_CONLY | D_C99 },
  { "return",		RID_RETURN,	0 },
  { "short",		RID_SHORT,	0 },
  { "signed",		RID_SIGNED,	0 },
  { "sizeof",		RID_SIZEOF,	0 },
  { "static",		RID_STATIC,	0 },
  { "static_assert",    RID_STATIC_ASSERT, D_CXXONLY | D_CXX0X | D_CXXWARN },
  { "static_cast",	RID_STATCAST,	D_CXXONLY | D_CXXWARN },
  { "struct",		RID_STRUCT,	0 },
  { "switch",		RID_SWITCH,	0 },
  { "template",		RID_TEMPLATE,	D_CXXONLY | D_CXXWARN },
  { "this",		RID_THIS,	D_CXXONLY | D_CXXWARN },
  { "throw",		RID_THROW,	D_CXX_OBJC | D_CXXWARN },
  { "true",		RID_TRUE,	D_CXXONLY | D_CXXWARN },
  { "try",		RID_TRY,	D_CXX_OBJC | D_CXXWARN },
  { "typedef",		RID_TYPEDEF,	0 },
  { "typename",		RID_TYPENAME,	D_CXXONLY | D_CXXWARN },
  { "typeid",		RID_TYPEID,	D_CXXONLY | D_CXXWARN },
  { "typeof",		RID_TYPEOF,	D_ASM | D_EXT },
  { "union",		RID_UNION,	0 },
  { "unsigned",		RID_UNSIGNED,	0 },
  { "using",		RID_USING,	D_CXXONLY | D_CXXWARN },
  { "virtual",		RID_VIRTUAL,	D_CXXONLY | D_CXXWARN },
  { "void",		RID_VOID,	0 },
  { "volatile",		RID_VOLATILE,	0 },
  { "wchar_t",		RID_WCHAR,	D_CXXONLY },
  { "while",		RID_WHILE,	0 },
  /* These Objective-C keywords are recognized only immediately after
     an '@'.  */
  { "compatibility_alias", RID_AT_ALIAS,	D_OBJC },
  { "defs",		RID_AT_DEFS,		D_OBJC },
  { "encode",		RID_AT_ENCODE,		D_OBJC },
  { "end",		RID_AT_END,		D_OBJC },
  { "implementation",	RID_AT_IMPLEMENTATION,	D_OBJC },
  { "interface",	RID_AT_INTERFACE,	D_OBJC },
  { "protocol",		RID_AT_PROTOCOL,	D_OBJC },
  { "selector",		RID_AT_SELECTOR,	D_OBJC },
  { "finally",		RID_AT_FINALLY,		D_OBJC },
  { "synchronized",	RID_AT_SYNCHRONIZED,	D_OBJC },
  /* These are recognized only in protocol-qualifier context
     (see above) */
  { "bycopy",		RID_BYCOPY,		D_OBJC },
  { "byref",		RID_BYREF,		D_OBJC },
  { "in",		RID_IN,			D_OBJC },
  { "inout",		RID_INOUT,		D_OBJC },
  { "oneway",		RID_ONEWAY,		D_OBJC },
  { "out",		RID_OUT,		D_OBJC },
};

const unsigned int num_c_common_reswords =
  sizeof c_common_reswords / sizeof (struct c_common_resword);

/* Table of machine-independent attributes common to all C-like languages.  */
const struct attribute_spec c_common_attribute_table[] =
{
  /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
  { "packed",                 0, 0, false, false, false,
			      handle_packed_attribute },
  { "nocommon",               0, 0, true,  false, false,
			      handle_nocommon_attribute },
  { "common",                 0, 0, true,  false, false,
			      handle_common_attribute },
  /* FIXME: logically, noreturn attributes should be listed as
     "false, true, true" and apply to function types.  But implementing this
     would require all the places in the compiler that use TREE_THIS_VOLATILE
     on a decl to identify non-returning functions to be located and fixed
     to check the function type instead.  */
  { "noreturn",               0, 0, true,  false, false,
			      handle_noreturn_attribute },
  { "volatile",               0, 0, true,  false, false,
			      handle_noreturn_attribute },
  { "noinline",               0, 0, true,  false, false,
			      handle_noinline_attribute },
  { "always_inline",          0, 0, true,  false, false,
			      handle_always_inline_attribute },
  { "gnu_inline",             0, 0, true,  false, false,
			      handle_gnu_inline_attribute },
  { "artificial",             0, 0, true,  false, false,
			      handle_artificial_attribute },
  { "flatten",                0, 0, true,  false, false,
			      handle_flatten_attribute },
  { "used",                   0, 0, true,  false, false,
			      handle_used_attribute },
  { "unused",                 0, 0, false, false, false,
			      handle_unused_attribute },
  { "externally_visible",     0, 0, true,  false, false,
			      handle_externally_visible_attribute },
  /* The same comments as for noreturn attributes apply to const ones.  */
  { "const",                  0, 0, true,  false, false,
			      handle_const_attribute },
  { "transparent_union",      0, 0, false, false, false,
			      handle_transparent_union_attribute },
  { "constructor",            0, 1, true,  false, false,
			      handle_constructor_attribute },
  { "destructor",             0, 1, true,  false, false,
			      handle_destructor_attribute },
  { "mode",                   1, 1, false,  true, false,
			      handle_mode_attribute },
  { "section",                1, 1, true,  false, false,
			      handle_section_attribute },
  { "aligned",                0, 1, false, false, false,
			      handle_aligned_attribute },
  { "weak",                   0, 0, true,  false, false,
			      handle_weak_attribute },
  { "alias",                  1, 1, true,  false, false,
			      handle_alias_attribute },
  { "weakref",                0, 1, true,  false, false,
			      handle_weakref_attribute },
  { "no_instrument_function", 0, 0, true,  false, false,
			      handle_no_instrument_function_attribute },
  { "malloc",                 0, 0, true,  false, false,
			      handle_malloc_attribute },
  { "returns_twice",          0, 0, true,  false, false,
			      handle_returns_twice_attribute },
  { "no_stack_limit",         0, 0, true,  false, false,
			      handle_no_limit_stack_attribute },
  { "pure",                   0, 0, true,  false, false,
			      handle_pure_attribute },
  /* For internal use (marking of builtins) only.  The name contains space
     to prevent its usage in source code.  */
  { "no vops",                0, 0, true,  false, false,
			      handle_novops_attribute },
  { "deprecated",             0, 0, false, false, false,
			      handle_deprecated_attribute },
  { "vector_size",	      1, 1, false, true, false,
			      handle_vector_size_attribute },
  { "visibility",	      1, 1, false, false, false,
			      handle_visibility_attribute },
  { "tls_model",	      1, 1, true,  false, false,
			      handle_tls_model_attribute },
  { "nonnull",                0, -1, false, true, true,
			      handle_nonnull_attribute },
  { "nothrow",                0, 0, true,  false, false,
			      handle_nothrow_attribute },
  { "may_alias",	      0, 0, false, true, false, NULL },
  { "cleanup",		      1, 1, true, false, false,
			      handle_cleanup_attribute },
  { "warn_unused_result",     0, 0, false, true, true,
			      handle_warn_unused_result_attribute },
  { "sentinel",               0, 1, false, true, true,
			      handle_sentinel_attribute },
  /* For internal use (marking of builtins) only.  The name contains space
     to prevent its usage in source code.  */
  { "type generic",           0, 0, false, true, true,
			      handle_type_generic_attribute },
  { "alloc_size",	      1, 2, false, true, true,
			      handle_alloc_size_attribute },
  { "cold",                   0, 0, true,  false, false,
			      handle_cold_attribute },
  { "hot",                    0, 0, true,  false, false,
			      handle_hot_attribute },
  { "warning",		      1, 1, true,  false, false,
			      handle_error_attribute },
  { "error",		      1, 1, true,  false, false,
			      handle_error_attribute },
  { "target",                 1, -1, true, false, false,
			      handle_target_attribute },
  { "optimize",               1, -1, true, false, false,
			      handle_optimize_attribute },
  { NULL,                     0, 0, false, false, false, NULL }
};

/* Give the specifications for the format attributes, used by C and all
   descendants.  */

const struct attribute_spec c_common_format_attribute_table[] =
{
  /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
  { "format",                 3, 3, false, true,  true,
			      handle_format_attribute },
  { "format_arg",             1, 1, false, true,  true,
			      handle_format_arg_attribute },
  { NULL,                     0, 0, false, false, false, NULL }
};

/* Push current bindings for the function name VAR_DECLS.  */

void
start_fname_decls (void)
{
  unsigned ix;
  tree saved = NULL_TREE;

  for (ix = 0; fname_vars[ix].decl; ix++)
    {
      tree decl = *fname_vars[ix].decl;

      if (decl)
	{
	  saved = tree_cons (decl, build_int_cst (NULL_TREE, ix), saved);
	  *fname_vars[ix].decl = NULL_TREE;
	}
    }
  if (saved || saved_function_name_decls)
    /* Normally they'll have been NULL, so only push if we've got a
       stack, or they are non-NULL.  */
    saved_function_name_decls = tree_cons (saved, NULL_TREE,
					   saved_function_name_decls);
}

/* Finish up the current bindings, adding them into the current function's
   statement tree.  This must be done _before_ finish_stmt_tree is called.
   If there is no current function, we must be at file scope and no statements
   are involved. Pop the previous bindings.  */

void
finish_fname_decls (void)
{
  unsigned ix;
  tree stmts = NULL_TREE;
  tree stack = saved_function_name_decls;

  for (; stack && TREE_VALUE (stack); stack = TREE_CHAIN (stack))
    append_to_statement_list (TREE_VALUE (stack), &stmts);

  if (stmts)
    {
      tree *bodyp = &DECL_SAVED_TREE (current_function_decl);

      if (TREE_CODE (*bodyp) == BIND_EXPR)
	bodyp = &BIND_EXPR_BODY (*bodyp);

      append_to_statement_list_force (*bodyp, &stmts);
      *bodyp = stmts;
    }

  for (ix = 0; fname_vars[ix].decl; ix++)
    *fname_vars[ix].decl = NULL_TREE;

  if (stack)
    {
      /* We had saved values, restore them.  */
      tree saved;

      for (saved = TREE_PURPOSE (stack); saved; saved = TREE_CHAIN (saved))
	{
	  tree decl = TREE_PURPOSE (saved);
	  unsigned ix = TREE_INT_CST_LOW (TREE_VALUE (saved));

	  *fname_vars[ix].decl = decl;
	}
      stack = TREE_CHAIN (stack);
    }
  saved_function_name_decls = stack;
}

/* Return the text name of the current function, suitably prettified
   by PRETTY_P.  Return string must be freed by caller.  */

const char *
fname_as_string (int pretty_p)
{
  const char *name = "top level";
  char *namep;
  int vrb = 2, len;
  cpp_string cstr = { 0, 0 }, strname;

  if (!pretty_p)
    {
      name = "";
      vrb = 0;
    }

  if (current_function_decl)
    name = lang_hooks.decl_printable_name (current_function_decl, vrb);

  len = strlen (name) + 3; /* Two for '"'s.  One for NULL.  */

  namep = XNEWVEC (char, len);
  snprintf (namep, len, "\"%s\"", name);
  strname.text = (unsigned char *) namep;
  strname.len = len - 1;

  if (cpp_interpret_string (parse_in, &strname, 1, &cstr, CPP_STRING))
    {
      XDELETEVEC (namep);
      return (const char *) cstr.text;
    }

  return namep;
}

/* Return the VAR_DECL for a const char array naming the current
   function. If the VAR_DECL has not yet been created, create it
   now. RID indicates how it should be formatted and IDENTIFIER_NODE
   ID is its name (unfortunately C and C++ hold the RID values of
   keywords in different places, so we can't derive RID from ID in
   this language independent code. LOC is the location of the
   function.  */

tree
fname_decl (location_t loc, unsigned int rid, tree id)
{
  unsigned ix;
  tree decl = NULL_TREE;

  for (ix = 0; fname_vars[ix].decl; ix++)
    if (fname_vars[ix].rid == rid)
      break;

  decl = *fname_vars[ix].decl;
  if (!decl)
    {
      /* If a tree is built here, it would normally have the lineno of
	 the current statement.  Later this tree will be moved to the
	 beginning of the function and this line number will be wrong.
	 To avoid this problem set the lineno to 0 here; that prevents
	 it from appearing in the RTL.  */
      tree stmts;
      location_t saved_location = input_location;
      input_location = UNKNOWN_LOCATION;

      stmts = push_stmt_list ();
      decl = (*make_fname_decl) (id, fname_vars[ix].pretty);
      stmts = pop_stmt_list (stmts);
      if (!IS_EMPTY_STMT (stmts))
	saved_function_name_decls
	  = tree_cons (decl, stmts, saved_function_name_decls);
      *fname_vars[ix].decl = decl;
      input_location = saved_location;
    }
  if (!ix && !current_function_decl)
    pedwarn (loc, 0, "%qD is not defined outside of function scope", decl);

  return decl;
}

/* Given a STRING_CST, give it a suitable array-of-chars data type.  */

tree
fix_string_type (tree value)
{
  int length = TREE_STRING_LENGTH (value);
  int nchars;
  tree e_type, i_type, a_type;

  /* Compute the number of elements, for the array type.  */
  if (TREE_TYPE (value) == char_array_type_node || !TREE_TYPE (value))
    {
      nchars = length;
      e_type = char_type_node;
    }
  else if (TREE_TYPE (value) == char16_array_type_node)
    {
      nchars = length / (TYPE_PRECISION (char16_type_node) / BITS_PER_UNIT);
      e_type = char16_type_node;
    }
  else if (TREE_TYPE (value) == char32_array_type_node)
    {
      nchars = length / (TYPE_PRECISION (char32_type_node) / BITS_PER_UNIT);
      e_type = char32_type_node;
    }
  else
    {
      nchars = length / (TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT);
      e_type = wchar_type_node;
    }

  /* C89 2.2.4.1, C99 5.2.4.1 (Translation limits).  The analogous
     limit in C++98 Annex B is very large (65536) and is not normative,
     so we do not diagnose it (warn_overlength_strings is forced off
     in c_common_post_options).  */
  if (warn_overlength_strings)
    {
      const int nchars_max = flag_isoc99 ? 4095 : 509;
      const int relevant_std = flag_isoc99 ? 99 : 90;
      if (nchars - 1 > nchars_max)
	/* Translators: The %d after 'ISO C' will be 90 or 99.  Do not
	   separate the %d from the 'C'.  'ISO' should not be
	   translated, but it may be moved after 'C%d' in languages
	   where modifiers follow nouns.  */
	pedwarn (input_location, OPT_Woverlength_strings,
		 "string length %qd is greater than the length %qd "
		 "ISO C%d compilers are required to support",
		 nchars - 1, nchars_max, relevant_std);
    }

  /* Create the array type for the string constant.  The ISO C++
     standard says that a string literal has type `const char[N]' or
     `const wchar_t[N]'.  We use the same logic when invoked as a C
     front-end with -Wwrite-strings.
     ??? We should change the type of an expression depending on the
     state of a warning flag.  We should just be warning -- see how
     this is handled in the C++ front-end for the deprecated implicit
     conversion from string literals to `char*' or `wchar_t*'.

     The C++ front end relies on TYPE_MAIN_VARIANT of a cv-qualified
     array type being the unqualified version of that type.
     Therefore, if we are constructing an array of const char, we must
     construct the matching unqualified array type first.  The C front
     end does not require this, but it does no harm, so we do it
     unconditionally.  */
  i_type = build_index_type (build_int_cst (NULL_TREE, nchars - 1));
  a_type = build_array_type (e_type, i_type);
  if (c_dialect_cxx() || warn_write_strings)
    a_type = c_build_qualified_type (a_type, TYPE_QUAL_CONST);

  TREE_TYPE (value) = a_type;
  TREE_CONSTANT (value) = 1;
  TREE_READONLY (value) = 1;
  TREE_STATIC (value) = 1;
  return value;
}

/* Print a warning if a constant expression had overflow in folding.
   Invoke this function on every expression that the language
   requires to be a constant expression.
   Note the ANSI C standard says it is erroneous for a
   constant expression to overflow.  */

void
constant_expression_warning (tree value)
{
  if (warn_overflow && pedantic 
      && (TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST
	  || TREE_CODE (value) == FIXED_CST
	  || TREE_CODE (value) == VECTOR_CST
	  || TREE_CODE (value) == COMPLEX_CST)
      && TREE_OVERFLOW (value))
    pedwarn (input_location, OPT_Woverflow, "overflow in constant expression");
}

/* The same as above but print an unconditional error.  */
void
constant_expression_error (tree value)
{
  if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST
       || TREE_CODE (value) == FIXED_CST
       || TREE_CODE (value) == VECTOR_CST
       || TREE_CODE (value) == COMPLEX_CST)
      && TREE_OVERFLOW (value))
    error ("overflow in constant expression");
}

/* Print a warning if an expression had overflow in folding and its
   operands hadn't.

   Invoke this function on every expression that
   (1) appears in the source code, and
   (2) is a constant expression that overflowed, and
   (3) is not already checked by convert_and_check;
   however, do not invoke this function on operands of explicit casts
   or when the expression is the result of an operator and any operand
   already overflowed.  */

void
overflow_warning (tree value)
{
  if (skip_evaluation) return;

  switch (TREE_CODE (value))
    {
    case INTEGER_CST:
      warning (OPT_Woverflow, "integer overflow in expression");
      break;
      
    case REAL_CST:
      warning (OPT_Woverflow, "floating point overflow in expression");
      break;
      
    case FIXED_CST:
      warning (OPT_Woverflow, "fixed-point overflow in expression");
      break;

    case VECTOR_CST:
      warning (OPT_Woverflow, "vector overflow in expression");
      break;
      
    case COMPLEX_CST:
      if (TREE_CODE (TREE_REALPART (value)) == INTEGER_CST)
	warning (OPT_Woverflow, "complex integer overflow in expression");
      else if (TREE_CODE (TREE_REALPART (value)) == REAL_CST)
	warning (OPT_Woverflow, "complex floating point overflow in expression");
      break;

    default:
      break;
    }
}


/* Warn about use of a logical || / && operator being used in a
   context where it is likely that the bitwise equivalent was intended
   by the programmer. CODE is the TREE_CODE of the operator, ARG1
   and ARG2 the arguments.  */

void
warn_logical_operator (enum tree_code code, tree arg1, tree
    arg2)
{
  switch (code)
    {
      case TRUTH_ANDIF_EXPR:
      case TRUTH_ORIF_EXPR:
      case TRUTH_OR_EXPR:
      case TRUTH_AND_EXPR:
	if (!TREE_NO_WARNING (arg1)
	    && INTEGRAL_TYPE_P (TREE_TYPE (arg1))
	    && !CONSTANT_CLASS_P (arg1)
	    && TREE_CODE (arg2) == INTEGER_CST
	    && !integer_zerop (arg2))
	  {
	    warning (OPT_Wlogical_op,
		     "logical %<%s%> with non-zero constant "
		     "will always evaluate as true",
		     ((code == TRUTH_ANDIF_EXPR)
		      || (code == TRUTH_AND_EXPR)) ? "&&" : "||");
	    TREE_NO_WARNING (arg1) = true;
	  }
	break;
      default:
	break;
    }
}


/* Print a warning about casts that might indicate violation
   of strict aliasing rules if -Wstrict-aliasing is used and
   strict aliasing mode is in effect. OTYPE is the original
   TREE_TYPE of EXPR, and TYPE the type we're casting to. */

bool
strict_aliasing_warning (tree otype, tree type, tree expr)
{
  if (!(flag_strict_aliasing
	&& POINTER_TYPE_P (type)
	&& POINTER_TYPE_P (otype)
	&& !VOID_TYPE_P (TREE_TYPE (type)))
      /* If the type we are casting to is a ref-all pointer
         dereferencing it is always valid.  */
      || TYPE_REF_CAN_ALIAS_ALL (type))
    return false;

  if ((warn_strict_aliasing > 1) && TREE_CODE (expr) == ADDR_EXPR
      && (DECL_P (TREE_OPERAND (expr, 0))
          || handled_component_p (TREE_OPERAND (expr, 0))))
    {
      /* Casting the address of an object to non void pointer. Warn
         if the cast breaks type based aliasing.  */
      if (!COMPLETE_TYPE_P (TREE_TYPE (type)) && warn_strict_aliasing == 2)
	{
	  warning (OPT_Wstrict_aliasing, "type-punning to incomplete type "
		   "might break strict-aliasing rules");
	  return true;
	}
      else
        {
          /* warn_strict_aliasing >= 3.   This includes the default (3).  
             Only warn if the cast is dereferenced immediately.  */
          alias_set_type set1 =
	    get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
          alias_set_type set2 = get_alias_set (TREE_TYPE (type));

          if (set1 != set2 && set2 != 0
	      && (set1 == 0 || !alias_sets_conflict_p (set1, set2)))
	    {
	      warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
		       "pointer will break strict-aliasing rules");
	      return true;
	    }
          else if (warn_strict_aliasing == 2
		   && !alias_sets_must_conflict_p (set1, set2))
	    {
	      warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
		       "pointer might break strict-aliasing rules");
	      return true;
	    }
        }
    }
  else
    if ((warn_strict_aliasing == 1) && !VOID_TYPE_P (TREE_TYPE (otype)))
      {
        /* At this level, warn for any conversions, even if an address is
           not taken in the same statement.  This will likely produce many
           false positives, but could be useful to pinpoint problems that
           are not revealed at higher levels.  */
        alias_set_type set1 = get_alias_set (TREE_TYPE (otype));
        alias_set_type set2 = get_alias_set (TREE_TYPE (type));
        if (!COMPLETE_TYPE_P (type)
            || !alias_sets_must_conflict_p (set1, set2))
	  {
            warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
                     "pointer might break strict-aliasing rules");
            return true;
          }
      }

  return false;
}

/* Warn for unlikely, improbable, or stupid DECL declarations
   of `main'.  */

void
check_main_parameter_types (tree decl)
{
  tree args;
  int argct = 0;

  for (args = TYPE_ARG_TYPES (TREE_TYPE (decl)); args;
      args = TREE_CHAIN (args))
   {
     tree type = args ? TREE_VALUE (args) : 0;

     if (type == void_type_node || type == error_mark_node )
       break;

     ++argct;
     switch (argct)
       {
       case 1:
         if (TYPE_MAIN_VARIANT (type) != integer_type_node)
           pedwarn (input_location, OPT_Wmain, "first argument of %q+D should be %<int%>", 
		    decl);
         break;

       case 2:
         if (TREE_CODE (type) != POINTER_TYPE
             || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
             || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
                 != char_type_node))
           pedwarn (input_location, OPT_Wmain, "second argument of %q+D should be %<char **%>",
		    decl);
         break;

       case 3:
         if (TREE_CODE (type) != POINTER_TYPE
             || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
             || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
                 != char_type_node))
	   pedwarn (input_location, OPT_Wmain, "third argument of %q+D should probably be "
		    "%<char **%>", decl);
         break;
       }
   }

  /* It is intentional that this message does not mention the third
    argument because it's only mentioned in an appendix of the
    standard.  */
  if (argct > 0 && (argct < 2 || argct > 3))
    pedwarn (input_location, OPT_Wmain, "%q+D takes only zero or two arguments", decl);
}

/* True if pointers to distinct types T1 and T2 can be converted to
   each other without an explicit cast.  Only returns true for opaque
   vector types.  */
bool
vector_targets_convertible_p (const_tree t1, const_tree t2)
{
  if (TREE_CODE (t1) == VECTOR_TYPE && TREE_CODE (t2) == VECTOR_TYPE
      && (targetm.vector_opaque_p (t1) || targetm.vector_opaque_p (t2))
      && tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2)))
    return true;

  return false;
}

/* True if vector types T1 and T2 can be converted to each other
   without an explicit cast.  If EMIT_LAX_NOTE is true, and T1 and T2
   can only be converted with -flax-vector-conversions yet that is not
   in effect, emit a note telling the user about that option if such
   a note has not previously been emitted.  */
bool
vector_types_convertible_p (const_tree t1, const_tree t2, bool emit_lax_note)
{
  static bool emitted_lax_note = false;
  bool convertible_lax;

  if ((targetm.vector_opaque_p (t1) || targetm.vector_opaque_p (t2))
      && tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2)))
    return true;

  convertible_lax =
    (tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2))
     && (TREE_CODE (TREE_TYPE (t1)) != REAL_TYPE ||
	 TYPE_PRECISION (t1) == TYPE_PRECISION (t2))
     && (INTEGRAL_TYPE_P (TREE_TYPE (t1))
	 == INTEGRAL_TYPE_P (TREE_TYPE (t2))));

  if (!convertible_lax || flag_lax_vector_conversions)
    return convertible_lax;

  if (TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
      && lang_hooks.types_compatible_p (TREE_TYPE (t1), TREE_TYPE (t2)))
    return true;

  if (emit_lax_note && !emitted_lax_note)
    {
      emitted_lax_note = true;
      inform (input_location, "use -flax-vector-conversions to permit "
              "conversions between vectors with differing "
              "element types or numbers of subparts");
    }

  return false;
}

/* This is a helper function of build_binary_op.

   For certain operations if both args were extended from the same
   smaller type, do the arithmetic in that type and then extend.

   BITWISE indicates a bitwise operation.
   For them, this optimization is safe only if
   both args are zero-extended or both are sign-extended.
   Otherwise, we might change the result.
   Eg, (short)-1 | (unsigned short)-1 is (int)-1
   but calculated in (unsigned short) it would be (unsigned short)-1.  
*/
tree shorten_binary_op (tree result_type, tree op0, tree op1, bool bitwise)
{
  int unsigned0, unsigned1;
  tree arg0, arg1;
  int uns;
  tree type;

  /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
     excessive narrowing when we call get_narrower below.  For
     example, suppose that OP0 is of unsigned int extended
     from signed char and that RESULT_TYPE is long long int.
     If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
     like
     
     (long long int) (unsigned int) signed_char

     which get_narrower would narrow down to
     
     (unsigned int) signed char
     
     If we do not cast OP0 first, get_narrower would return
     signed_char, which is inconsistent with the case of the
     explicit cast.  */
  op0 = convert (result_type, op0);
  op1 = convert (result_type, op1);

  arg0 = get_narrower (op0, &unsigned0);
  arg1 = get_narrower (op1, &unsigned1);

  /* UNS is 1 if the operation to be done is an unsigned one.  */
  uns = TYPE_UNSIGNED (result_type);

  /* Handle the case that OP0 (or OP1) does not *contain* a conversion
     but it *requires* conversion to FINAL_TYPE.  */
  
  if ((TYPE_PRECISION (TREE_TYPE (op0))
       == TYPE_PRECISION (TREE_TYPE (arg0)))
      && TREE_TYPE (op0) != result_type)
    unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
  if ((TYPE_PRECISION (TREE_TYPE (op1))
       == TYPE_PRECISION (TREE_TYPE (arg1)))
      && TREE_TYPE (op1) != result_type)
    unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
  
  /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
  
  /* For bitwise operations, signedness of nominal type
     does not matter.  Consider only how operands were extended.  */
  if (bitwise)
    uns = unsigned0;
  
  /* Note that in all three cases below we refrain from optimizing
     an unsigned operation on sign-extended args.
     That would not be valid.  */
  
  /* Both args variable: if both extended in same way
     from same width, do it in that width.
     Do it unsigned if args were zero-extended.  */
  if ((TYPE_PRECISION (TREE_TYPE (arg0))
       < TYPE_PRECISION (result_type))
      && (TYPE_PRECISION (TREE_TYPE (arg1))
	  == TYPE_PRECISION (TREE_TYPE (arg0)))
      && unsigned0 == unsigned1
      && (unsigned0 || !uns))
    return c_common_signed_or_unsigned_type
      (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));

  else if (TREE_CODE (arg0) == INTEGER_CST
	   && (unsigned1 || !uns)
	   && (TYPE_PRECISION (TREE_TYPE (arg1))
	       < TYPE_PRECISION (result_type))
	   && (type
	       = c_common_signed_or_unsigned_type (unsigned1,
						   TREE_TYPE (arg1)))
	   && !POINTER_TYPE_P (type)
	   && int_fits_type_p (arg0, type))
    return type;

  else if (TREE_CODE (arg1) == INTEGER_CST
	   && (unsigned0 || !uns)
	   && (TYPE_PRECISION (TREE_TYPE (arg0))
	       < TYPE_PRECISION (result_type))
	   && (type
	       = c_common_signed_or_unsigned_type (unsigned0,
						   TREE_TYPE (arg0)))
	   && !POINTER_TYPE_P (type)
	   && int_fits_type_p (arg1, type))
    return type;

  return result_type;
}

/* Warns if the conversion of EXPR to TYPE may alter a value.
   This is a helper function for warnings_for_convert_and_check.  */

static void
conversion_warning (tree type, tree expr)
{
  bool give_warning = false;

  int i;
  const int expr_num_operands = TREE_OPERAND_LENGTH (expr);
  tree expr_type = TREE_TYPE (expr);

  if (!warn_conversion && !warn_sign_conversion)
    return;

  /* If any operand is artificial, then this expression was generated
     by the compiler and we do not warn.  */
  for (i = 0; i < expr_num_operands; i++)
    {
      tree op = TREE_OPERAND (expr, i);
      if (op && DECL_P (op) && DECL_ARTIFICIAL (op))
	return;
    }

  switch (TREE_CODE (expr))
    {
    case EQ_EXPR:
    case NE_EXPR:
    case LE_EXPR:
    case GE_EXPR:
    case LT_EXPR:
    case GT_EXPR:
    case TRUTH_ANDIF_EXPR:
    case TRUTH_ORIF_EXPR:
    case TRUTH_AND_EXPR:
    case TRUTH_OR_EXPR:
    case TRUTH_XOR_EXPR:
    case TRUTH_NOT_EXPR:
      /* Conversion from boolean to a signed:1 bit-field (which only
	 can hold the values 0 and -1) doesn't lose information - but
	 it does change the value.  */
      if (TYPE_PRECISION (type) == 1 && !TYPE_UNSIGNED (type)) 
	warning (OPT_Wconversion,
                 "conversion to %qT from boolean expression", type);
      return;

    case REAL_CST:
    case INTEGER_CST:

      /* Warn for real constant that is not an exact integer converted
         to integer type.  */
      if (TREE_CODE (expr_type) == REAL_TYPE
          && TREE_CODE (type) == INTEGER_TYPE)
        {
          if (!real_isinteger (TREE_REAL_CST_PTR (expr), TYPE_MODE (expr_type)))
            give_warning = true;
        }
      /* Warn for an integer constant that does not fit into integer type.  */
      else if (TREE_CODE (expr_type) == INTEGER_TYPE
               && TREE_CODE (type) == INTEGER_TYPE
               && !int_fits_type_p (expr, type))
        {
          if (TYPE_UNSIGNED (type) && !TYPE_UNSIGNED (expr_type) 
	      && tree_int_cst_sgn (expr) < 0)
	    warning (OPT_Wsign_conversion,
		     "negative integer implicitly converted to unsigned type");
          else if (!TYPE_UNSIGNED (type) && TYPE_UNSIGNED (expr_type))
	    warning (OPT_Wsign_conversion,  "conversion of unsigned constant "
		     "value to negative integer");
	  else
	    give_warning = true;
        }
      else if (TREE_CODE (type) == REAL_TYPE)
        {
          /* Warn for an integer constant that does not fit into real type.  */
          if (TREE_CODE (expr_type) == INTEGER_TYPE)
            {
              REAL_VALUE_TYPE a = real_value_from_int_cst (0, expr);
              if (!exact_real_truncate (TYPE_MODE (type), &a))
                give_warning = true;
            }
          /* Warn for a real constant that does not fit into a smaller
             real type.  */
          else if (TREE_CODE (expr_type) == REAL_TYPE
                   && TYPE_PRECISION (type) < TYPE_PRECISION (expr_type))
            {
              REAL_VALUE_TYPE a = TREE_REAL_CST (expr);
              if (!exact_real_truncate (TYPE_MODE (type), &a))
                give_warning = true;
            }
        }

      if (give_warning)
        warning (OPT_Wconversion,
                 "conversion to %qT alters %qT constant value",
                 type, expr_type);

      return;

    case COND_EXPR:
      {
	/* In case of COND_EXPR, if both operands are constants or
	   COND_EXPR, then we do not care about the type of COND_EXPR,
	   only about the conversion of each operand.  */
	tree op1 = TREE_OPERAND (expr, 1);
	tree op2 = TREE_OPERAND (expr, 2);

	if ((TREE_CODE (op1) == REAL_CST || TREE_CODE (op1) == INTEGER_CST 
	     || TREE_CODE (op1) == COND_EXPR)
	    && (TREE_CODE (op2) == REAL_CST || TREE_CODE (op2) == INTEGER_CST
		|| TREE_CODE (op2) == COND_EXPR))
	  {
	    conversion_warning (type, op1);
	    conversion_warning (type, op2);
	    return;
	  }
	/* Fall through.  */
      }

    default: /* 'expr' is not a constant.  */

      /* Warn for real types converted to integer types.  */
      if (TREE_CODE (expr_type) == REAL_TYPE
          && TREE_CODE (type) == INTEGER_TYPE)
        give_warning = true;

      else if (TREE_CODE (expr_type) == INTEGER_TYPE
               && TREE_CODE (type) == INTEGER_TYPE)
        {
	  /* Don't warn about unsigned char y = 0xff, x = (int) y;  */
	  expr = get_unwidened (expr, 0);
	  expr_type = TREE_TYPE (expr);

	  /* Don't warn for short y; short x = ((int)y & 0xff);  */
	  if (TREE_CODE (expr) == BIT_AND_EXPR 
		|| TREE_CODE (expr) == BIT_IOR_EXPR 
	      || TREE_CODE (expr) == BIT_XOR_EXPR)
	    {
	      /* If both args were extended from a shortest type,
		 use that type if that is safe.  */
	      expr_type = shorten_binary_op (expr_type, 
					     TREE_OPERAND (expr, 0), 
					     TREE_OPERAND (expr, 1), 
					     /* bitwise */1);

	      if (TREE_CODE (expr) == BIT_AND_EXPR)
		{
		  tree op0 = TREE_OPERAND (expr, 0);
		  tree op1 = TREE_OPERAND (expr, 1);
		  bool unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
		  bool unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));

		  /* If one of the operands is a non-negative constant
		     that fits in the target type, then the type of the
		     other operand does not matter. */
		  if ((TREE_CODE (op0) == INTEGER_CST
		       && int_fits_type_p (op0, c_common_signed_type (type))
		       && int_fits_type_p (op0, c_common_unsigned_type (type)))
		      || (TREE_CODE (op1) == INTEGER_CST
			  && int_fits_type_p (op1, c_common_signed_type (type))
			  && int_fits_type_p (op1, 
					      c_common_unsigned_type (type))))
		    return;
		  /* If constant is unsigned and fits in the target
		     type, then the result will also fit.  */
		  else if ((TREE_CODE (op0) == INTEGER_CST
			    && unsigned0 
			    && int_fits_type_p (op0, type))
			   || (TREE_CODE (op1) == INTEGER_CST
			       && unsigned1
			       && int_fits_type_p (op1, type)))
		    return;
		}
	    }
          /* Warn for integer types converted to smaller integer types.  */
	  if (TYPE_PRECISION (type) < TYPE_PRECISION (expr_type)) 
	    give_warning = true;

	  /* When they are the same width but different signedness,
	     then the value may change.  */
	  else if ((TYPE_PRECISION (type) == TYPE_PRECISION (expr_type)
		    && TYPE_UNSIGNED (expr_type) != TYPE_UNSIGNED (type))
		   /* Even when converted to a bigger type, if the type is
		      unsigned but expr is signed, then negative values
		      will be changed.  */
		   || (TYPE_UNSIGNED (type) && !TYPE_UNSIGNED (expr_type)))
	    warning (OPT_Wsign_conversion, "conversion to %qT from %qT "
		     "may change the sign of the result",
		     type, expr_type);
        }

      /* Warn for integer types converted to real types if and only if
         all the range of values of the integer type cannot be
         represented by the real type.  */
      else if (TREE_CODE (expr_type) == INTEGER_TYPE
               && TREE_CODE (type) == REAL_TYPE)
        {
          tree type_low_bound = TYPE_MIN_VALUE (expr_type);
          tree type_high_bound = TYPE_MAX_VALUE (expr_type);
          REAL_VALUE_TYPE real_low_bound 
	    = real_value_from_int_cst (0, type_low_bound);
          REAL_VALUE_TYPE real_high_bound 
	    = real_value_from_int_cst (0, type_high_bound);

          if (!exact_real_truncate (TYPE_MODE (type), &real_low_bound)
              || !exact_real_truncate (TYPE_MODE (type), &real_high_bound))
            give_warning = true;
        }

      /* Warn for real types converted to smaller real types.  */
      else if (TREE_CODE (expr_type) == REAL_TYPE
               && TREE_CODE (type) == REAL_TYPE
               && TYPE_PRECISION (type) < TYPE_PRECISION (expr_type))
        give_warning = true;


      if (give_warning)
        warning (OPT_Wconversion,
                 "conversion to %qT from %qT may alter its value",
                 type, expr_type);
    }
}

/* Produce warnings after a conversion. RESULT is the result of
   converting EXPR to TYPE.  This is a helper function for
   convert_and_check and cp_convert_and_check.  */

void
warnings_for_convert_and_check (tree type, tree expr, tree result)
{
  if (TREE_CODE (expr) == INTEGER_CST
      && (TREE_CODE (type) == INTEGER_TYPE
          || TREE_CODE (type) == ENUMERAL_TYPE)
      && !int_fits_type_p (expr, type))
    {
      /* Do not diagnose overflow in a constant expression merely
         because a conversion overflowed.  */
      if (TREE_OVERFLOW (result))
        TREE_OVERFLOW (result) = TREE_OVERFLOW (expr);

      if (TYPE_UNSIGNED (type))
        {
          /* This detects cases like converting -129 or 256 to
             unsigned char.  */
          if (!int_fits_type_p (expr, c_common_signed_type (type)))
            warning (OPT_Woverflow,
                     "large integer implicitly truncated to unsigned type");
          else
            conversion_warning (type, expr);
        }
      else if (!int_fits_type_p (expr, c_common_unsigned_type (type))) 
	warning (OPT_Woverflow,
		 "overflow in implicit constant conversion");
      /* No warning for converting 0x80000000 to int.  */
      else if (pedantic
	       && (TREE_CODE (TREE_TYPE (expr)) != INTEGER_TYPE
		   || TYPE_PRECISION (TREE_TYPE (expr))
		   != TYPE_PRECISION (type)))
	warning (OPT_Woverflow,
		 "overflow in implicit constant conversion");

      else
	conversion_warning (type, expr);
    }
  else if ((TREE_CODE (result) == INTEGER_CST
	    || TREE_CODE (result) == FIXED_CST) && TREE_OVERFLOW (result))
    warning (OPT_Woverflow,
             "overflow in implicit constant conversion");
  else
    conversion_warning (type, expr);
}


/* Convert EXPR to TYPE, warning about conversion problems with constants.
   Invoke this function on every expression that is converted implicitly,
   i.e. because of language rules and not because of an explicit cast.  */

tree
convert_and_check (tree type, tree expr)
{
  tree result;

  if (TREE_TYPE (expr) == type)
    return expr;
  
  result = convert (type, expr);

  if (!skip_evaluation && !TREE_OVERFLOW_P (expr) && result != error_mark_node)
    warnings_for_convert_and_check (type, expr, result);

  return result;
}

/* A node in a list that describes references to variables (EXPR), which are
   either read accesses if WRITER is zero, or write accesses, in which case
   WRITER is the parent of EXPR.  */
struct tlist
{
  struct tlist *next;
  tree expr, writer;
};

/* Used to implement a cache the results of a call to verify_tree.  We only
   use this for SAVE_EXPRs.  */
struct tlist_cache
{
  struct tlist_cache *next;
  struct tlist *cache_before_sp;
  struct tlist *cache_after_sp;
  tree expr;
};

/* Obstack to use when allocating tlist structures, and corresponding
   firstobj.  */
static struct obstack tlist_obstack;
static char *tlist_firstobj = 0;

/* Keep track of the identifiers we've warned about, so we can avoid duplicate
   warnings.  */
static struct tlist *warned_ids;
/* SAVE_EXPRs need special treatment.  We process them only once and then
   cache the results.  */
static struct tlist_cache *save_expr_cache;

static void add_tlist (struct tlist **, struct tlist *, tree, int);
static void merge_tlist (struct tlist **, struct tlist *, int);
static void verify_tree (tree, struct tlist **, struct tlist **, tree);
static int warning_candidate_p (tree);
static void warn_for_collisions (struct tlist *);
static void warn_for_collisions_1 (tree, tree, struct tlist *, int);
static struct tlist *new_tlist (struct tlist *, tree, tree);

/* Create a new struct tlist and fill in its fields.  */
static struct tlist *
new_tlist (struct tlist *next, tree t, tree writer)
{
  struct tlist *l;
  l = XOBNEW (&tlist_obstack, struct tlist);
  l->next = next;
  l->expr = t;
  l->writer = writer;
  return l;
}

/* Add duplicates of the nodes found in ADD to the list *TO.  If EXCLUDE_WRITER
   is nonnull, we ignore any node we find which has a writer equal to it.  */

static void
add_tlist (struct tlist **to, struct tlist *add, tree exclude_writer, int copy)
{
  while (add)
    {
      struct tlist *next = add->next;
      if (!copy)
	add->next = *to;
      if (!exclude_writer || add->writer != exclude_writer)
	*to = copy ? new_tlist (*to, add->expr, add->writer) : add;
      add = next;
    }
}

/* Merge the nodes of ADD into TO.  This merging process is done so that for
   each variable that already exists in TO, no new node is added; however if
   there is a write access recorded in ADD, and an occurrence on TO is only
   a read access, then the occurrence in TO will be modified to record the
   write.  */

static void
merge_tlist (struct tlist **to, struct tlist *add, int copy)
{
  struct tlist **end = to;

  while (*end)
    end = &(*end)->next;

  while (add)
    {
      int found = 0;
      struct tlist *tmp2;
      struct tlist *next = add->next;

      for (tmp2 = *to; tmp2; tmp2 = tmp2->next)
	if (tmp2->expr == add->expr)
	  {
	    found = 1;
	    if (!tmp2->writer)
	      tmp2->writer = add->writer;
	  }
      if (!found)
	{
	  *end = copy ? add : new_tlist (NULL, add->expr, add->writer);
	  end = &(*end)->next;
	  *end = 0;
	}
      add = next;
    }
}

/* WRITTEN is a variable, WRITER is its parent.  Warn if any of the variable
   references in list LIST conflict with it, excluding reads if ONLY writers
   is nonzero.  */

static void
warn_for_collisions_1 (tree written, tree writer, struct tlist *list,
		       int only_writes)
{
  struct tlist *tmp;

  /* Avoid duplicate warnings.  */
  for (tmp = warned_ids; tmp; tmp = tmp->next)
    if (tmp->expr == written)
      return;

  while (list)
    {
      if (list->expr == written
	  && list->writer != writer
	  && (!only_writes || list->writer)
	  && DECL_NAME (list->expr))
	{
	  warned_ids = new_tlist (warned_ids, written, NULL_TREE);
	  warning_at (EXPR_HAS_LOCATION (writer)
		      ? EXPR_LOCATION (writer) : input_location,
		      OPT_Wsequence_point, "operation on %qE may be undefined",
		      list->expr);
	}
      list = list->next;
    }
}

/* Given a list LIST of references to variables, find whether any of these
   can cause conflicts due to missing sequence points.  */

static void
warn_for_collisions (struct tlist *list)
{
  struct tlist *tmp;

  for (tmp = list; tmp; tmp = tmp->next)
    {
      if (tmp->writer)
	warn_for_collisions_1 (tmp->expr, tmp->writer, list, 0);
    }
}

/* Return nonzero if X is a tree that can be verified by the sequence point
   warnings.  */
static int
warning_candidate_p (tree x)
{
  return TREE_CODE (x) == VAR_DECL || TREE_CODE (x) == PARM_DECL;
}

/* Walk the tree X, and record accesses to variables.  If X is written by the
   parent tree, WRITER is the parent.
   We store accesses in one of the two lists: PBEFORE_SP, and PNO_SP.  If this
   expression or its only operand forces a sequence point, then everything up
   to the sequence point is stored in PBEFORE_SP.  Everything else gets stored
   in PNO_SP.
   Once we return, we will have emitted warnings if any subexpression before
   such a sequence point could be undefined.  On a higher level, however, the
   sequence point may not be relevant, and we'll merge the two lists.

   Example: (b++, a) + b;
   The call that processes the COMPOUND_EXPR will store the increment of B
   in PBEFORE_SP, and the use of A in PNO_SP.  The higher-level call that
   processes the PLUS_EXPR will need to merge the two lists so that
   eventually, all accesses end up on the same list (and we'll warn about the
   unordered subexpressions b++ and b.

   A note on merging.  If we modify the former example so that our expression
   becomes
     (b++, b) + a
   care must be taken not simply to add all three expressions into the final
   PNO_SP list.  The function merge_tlist takes care of that by merging the
   before-SP list of the COMPOUND_EXPR into its after-SP list in a special
   way, so that no more than one access to B is recorded.  */

static void
verify_tree (tree x, struct tlist **pbefore_sp, struct tlist **pno_sp,
	     tree writer)
{
  struct tlist *tmp_before, *tmp_nosp, *tmp_list2, *tmp_list3;
  enum tree_code code;
  enum tree_code_class cl;

  /* X may be NULL if it is the operand of an empty statement expression
     ({ }).  */
  if (x == NULL)
    return;

 restart:
  code = TREE_CODE (x);
  cl = TREE_CODE_CLASS (code);

  if (warning_candidate_p (x))
    {
      *pno_sp = new_tlist (*pno_sp, x, writer);
      return;
    }

  switch (code)
    {
    case CONSTRUCTOR:
      return;

    case COMPOUND_EXPR:
    case TRUTH_ANDIF_EXPR:
    case TRUTH_ORIF_EXPR:
      tmp_before = tmp_nosp = tmp_list3 = 0;
      verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
      warn_for_collisions (tmp_nosp);
      merge_tlist (pbefore_sp, tmp_before, 0);
      merge_tlist (pbefore_sp, tmp_nosp, 0);
      verify_tree (TREE_OPERAND (x, 1), &tmp_list3, pno_sp, NULL_TREE);
      merge_tlist (pbefore_sp, tmp_list3, 0);
      return;

    case COND_EXPR:
      tmp_before = tmp_list2 = 0;
      verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_list2, NULL_TREE);
      warn_for_collisions (tmp_list2);
      merge_tlist (pbefore_sp, tmp_before, 0);
      merge_tlist (pbefore_sp, tmp_list2, 1);

      tmp_list3 = tmp_nosp = 0;
      verify_tree (TREE_OPERAND (x, 1), &tmp_list3, &tmp_nosp, NULL_TREE);
      warn_for_collisions (tmp_nosp);
      merge_tlist (pbefore_sp, tmp_list3, 0);

      tmp_list3 = tmp_list2 = 0;
      verify_tree (TREE_OPERAND (x, 2), &tmp_list3, &tmp_list2, NULL_TREE);
      warn_for_collisions (tmp_list2);
      merge_tlist (pbefore_sp, tmp_list3, 0);
      /* Rather than add both tmp_nosp and tmp_list2, we have to merge the
	 two first, to avoid warning for (a ? b++ : b++).  */
      merge_tlist (&tmp_nosp, tmp_list2, 0);
      add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
      return;

    case PREDECREMENT_EXPR:
    case PREINCREMENT_EXPR:
    case POSTDECREMENT_EXPR:
    case POSTINCREMENT_EXPR:
      verify_tree (TREE_OPERAND (x, 0), pno_sp, pno_sp, x);
      return;

    case MODIFY_EXPR:
      tmp_before = tmp_nosp = tmp_list3 = 0;
      verify_tree (TREE_OPERAND (x, 1), &tmp_before, &tmp_nosp, NULL_TREE);
      verify_tree (TREE_OPERAND (x, 0), &tmp_list3, &tmp_list3, x);
      /* Expressions inside the LHS are not ordered wrt. the sequence points
	 in the RHS.  Example:
	   *a = (a++, 2)
	 Despite the fact that the modification of "a" is in the before_sp
	 list (tmp_before), it conflicts with the use of "a" in the LHS.
	 We can handle this by adding the contents of tmp_list3
	 to those of tmp_before, and redoing the collision warnings for that
	 list.  */
      add_tlist (&tmp_before, tmp_list3, x, 1);
      warn_for_collisions (tmp_before);
      /* Exclude the LHS itself here; we first have to merge it into the
	 tmp_nosp list.  This is done to avoid warning for "a = a"; if we
	 didn't exclude the LHS, we'd get it twice, once as a read and once
	 as a write.  */
      add_tlist (pno_sp, tmp_list3, x, 0);
      warn_for_collisions_1 (TREE_OPERAND (x, 0), x, tmp_nosp, 1);

      merge_tlist (pbefore_sp, tmp_before, 0);
      if (warning_candidate_p (TREE_OPERAND (x, 0)))
	merge_tlist (&tmp_nosp, new_tlist (NULL, TREE_OPERAND (x, 0), x), 0);
      add_tlist (pno_sp, tmp_nosp, NULL_TREE, 1);
      return;

    case CALL_EXPR:
      /* We need to warn about conflicts among arguments and conflicts between
	 args and the function address.  Side effects of the function address,
	 however, are not ordered by the sequence point of the call.  */
      {
	call_expr_arg_iterator iter;
	tree arg;
	tmp_before = tmp_nosp = 0; 
	verify_tree (CALL_EXPR_FN (x), &tmp_before, &tmp_nosp, NULL_TREE);
	FOR_EACH_CALL_EXPR_ARG (arg, iter, x)
	  {
	    tmp_list2 = tmp_list3 = 0;
	    verify_tree (arg, &tmp_list2, &tmp_list3, NULL_TREE);
	    merge_tlist (&tmp_list3, tmp_list2, 0);
	    add_tlist (&tmp_before, tmp_list3, NULL_TREE, 0);
	  }
	add_tlist (&tmp_before, tmp_nosp, NULL_TREE, 0);
	warn_for_collisions (tmp_before);
	add_tlist (pbefore_sp, tmp_before, NULL_TREE, 0);
	return;
      }

    case TREE_LIST:
      /* Scan all the list, e.g. indices of multi dimensional array.  */
      while (x)
	{
	  tmp_before = tmp_nosp = 0;
	  verify_tree (TREE_VALUE (x), &tmp_before, &tmp_nosp, NULL_TREE);
	  merge_tlist (&tmp_nosp, tmp_before, 0);
	  add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
	  x = TREE_CHAIN (x);
	}
      return;

    case SAVE_EXPR:
      {
	struct tlist_cache *t;
	for (t = save_expr_cache; t; t = t->next)
	  if (t->expr == x)
	    break;

	if (!t)
	  {
	    t = XOBNEW (&tlist_obstack, struct tlist_cache);
	    t->next = save_expr_cache;
	    t->expr = x;
	    save_expr_cache = t;

	    tmp_before = tmp_nosp = 0;
	    verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
	    warn_for_collisions (tmp_nosp);

	    tmp_list3 = 0;
	    while (tmp_nosp)
	      {
		struct tlist *t = tmp_nosp;
		tmp_nosp = t->next;
		merge_tlist (&tmp_list3, t, 0);
	      }
	    t->cache_before_sp = tmp_before;
	    t->cache_after_sp = tmp_list3;
	  }
	merge_tlist (pbefore_sp, t->cache_before_sp, 1);
	add_tlist (pno_sp, t->cache_after_sp, NULL_TREE, 1);
	return;
      }

    case ADDR_EXPR:
      x = TREE_OPERAND (x, 0);
      if (DECL_P (x))
	return;
      writer = 0;
      goto restart;

    default:
      /* For other expressions, simply recurse on their operands.
	 Manual tail recursion for unary expressions.
	 Other non-expressions need not be processed.  */
      if (cl == tcc_unary)
	{
	  x = TREE_OPERAND (x, 0);
	  writer = 0;
	  goto restart;
	}
      else if (IS_EXPR_CODE_CLASS (cl))
	{
	  int lp;
	  int max = TREE_OPERAND_LENGTH (x);
	  for (lp = 0; lp < max; lp++)
	    {
	      tmp_before = tmp_nosp = 0;
	      verify_tree (TREE_OPERAND (x, lp), &tmp_before, &tmp_nosp, 0);
	      merge_tlist (&tmp_nosp, tmp_before, 0);
	      add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
	    }
	}
      return;
    }
}

/* Try to warn for undefined behavior in EXPR due to missing sequence
   points.  */

void
verify_sequence_points (tree expr)
{
  struct tlist *before_sp = 0, *after_sp = 0;

  warned_ids = 0;
  save_expr_cache = 0;
  if (tlist_firstobj == 0)
    {
      gcc_obstack_init (&tlist_obstack);
      tlist_firstobj = (char *) obstack_alloc (&tlist_obstack, 0);
    }

  verify_tree (expr, &before_sp, &after_sp, 0);
  warn_for_collisions (after_sp);
  obstack_free (&tlist_obstack, tlist_firstobj);
}

/* Validate the expression after `case' and apply default promotions.  */

static tree
check_case_value (tree value)
{
  if (value == NULL_TREE)
    return value;

  /* ??? Can we ever get nops here for a valid case value?  We
     shouldn't for C.  */
  STRIP_TYPE_NOPS (value);
  /* In C++, the following is allowed:

       const int i = 3;
       switch (...) { case i: ... }

     So, we try to reduce the VALUE to a constant that way.  */
  if (c_dialect_cxx ())
    {
      value = decl_constant_value (value);
      STRIP_TYPE_NOPS (value);
      value = fold (value);
    }

  if (TREE_CODE (value) == INTEGER_CST)
    /* Promote char or short to int.  */
    value = perform_integral_promotions (value);
  else if (value != error_mark_node)
    {
      error ("case label does not reduce to an integer constant");
      value = error_mark_node;
    }

  constant_expression_warning (value);

  return value;
}

/* See if the case values LOW and HIGH are in the range of the original
   type (i.e. before the default conversion to int) of the switch testing
   expression.
   TYPE is the promoted type of the testing expression, and ORIG_TYPE is
   the type before promoting it.  CASE_LOW_P is a pointer to the lower
   bound of the case label, and CASE_HIGH_P is the upper bound or NULL
   if the case is not a case range.
   The caller has to make sure that we are not called with NULL for
   CASE_LOW_P (i.e. the default case).
   Returns true if the case label is in range of ORIG_TYPE (saturated or
   untouched) or false if the label is out of range.  */

static bool
check_case_bounds (tree type, tree orig_type,
		   tree *case_low_p, tree *case_high_p)
{
  tree min_value, max_value;
  tree case_low = *case_low_p;
  tree case_high = case_high_p ? *case_high_p : case_low;

  /* If there was a problem with the original type, do nothing.  */
  if (orig_type == error_mark_node)
    return true;

  min_value = TYPE_MIN_VALUE (orig_type);
  max_value = TYPE_MAX_VALUE (orig_type);

  /* Case label is less than minimum for type.  */
  if (tree_int_cst_compare (case_low, min_value) < 0
      && tree_int_cst_compare (case_high, min_value) < 0)
    {
      warning (0, "case label value is less than minimum value for type");
      return false;
    }

  /* Case value is greater than maximum for type.  */
  if (tree_int_cst_compare (case_low, max_value) > 0
      && tree_int_cst_compare (case_high, max_value) > 0)
    {
      warning (0, "case label value exceeds maximum value for type");
      return false;
    }

  /* Saturate lower case label value to minimum.  */
  if (tree_int_cst_compare (case_high, min_value) >= 0
      && tree_int_cst_compare (case_low, min_value) < 0)
    {
      warning (0, "lower value in case label range"
	       " less than minimum value for type");
      case_low = min_value;
    }

  /* Saturate upper case label value to maximum.  */
  if (tree_int_cst_compare (case_low, max_value) <= 0
      && tree_int_cst_compare (case_high, max_value) > 0)
    {
      warning (0, "upper value in case label range"
	       " exceeds maximum value for type");
      case_high = max_value;
    }

  if (*case_low_p != case_low)
    *case_low_p = convert (type, case_low);
  if (case_high_p && *case_high_p != case_high)
    *case_high_p = convert (type, case_high);

  return true;
}

/* Return an integer type with BITS bits of precision,
   that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */

tree
c_common_type_for_size (unsigned int bits, int unsignedp)
{
  if (bits == TYPE_PRECISION (integer_type_node))
    return unsignedp ? unsigned_type_node : integer_type_node;

  if (bits == TYPE_PRECISION (signed_char_type_node))
    return unsignedp ? unsigned_char_type_node : signed_char_type_node;

  if (bits == TYPE_PRECISION (short_integer_type_node))
    return unsignedp ? short_unsigned_type_node : short_integer_type_node;

  if (bits == TYPE_PRECISION (long_integer_type_node))
    return unsignedp ? long_unsigned_type_node : long_integer_type_node;

  if (bits == TYPE_PRECISION (long_long_integer_type_node))
    return (unsignedp ? long_long_unsigned_type_node
	    : long_long_integer_type_node);

  if (bits == TYPE_PRECISION (widest_integer_literal_type_node))
    return (unsignedp ? widest_unsigned_literal_type_node
	    : widest_integer_literal_type_node);

  if (bits <= TYPE_PRECISION (intQI_type_node))
    return unsignedp ? unsigned_intQI_type_node : intQI_type_node;

  if (bits <= TYPE_PRECISION (intHI_type_node))
    return unsignedp ? unsigned_intHI_type_node : intHI_type_node;

  if (bits <= TYPE_PRECISION (intSI_type_node))
    return unsignedp ? unsigned_intSI_type_node : intSI_type_node;

  if (bits <= TYPE_PRECISION (intDI_type_node))
    return unsignedp ? unsigned_intDI_type_node : intDI_type_node;

  return 0;
}

/* Return a fixed-point type that has at least IBIT ibits and FBIT fbits
   that is unsigned if UNSIGNEDP is nonzero, otherwise signed;
   and saturating if SATP is nonzero, otherwise not saturating.  */

tree
c_common_fixed_point_type_for_size (unsigned int ibit, unsigned int fbit,
				    int unsignedp, int satp)
{
  enum machine_mode mode;
  if (ibit == 0)
    mode = unsignedp ? UQQmode : QQmode;
  else
    mode = unsignedp ? UHAmode : HAmode;

  for (; mode != VOIDmode; mode = GET_MODE_WIDER_MODE (mode))
    if (GET_MODE_IBIT (mode) >= ibit && GET_MODE_FBIT (mode) >= fbit)
      break;

  if (mode == VOIDmode || !targetm.scalar_mode_supported_p (mode))
    {
      sorry ("GCC cannot support operators with integer types and "
	     "fixed-point types that have too many integral and "
	     "fractional bits together");
      return 0;
    }

  return c_common_type_for_mode (mode, satp);
}

/* Used for communication between c_common_type_for_mode and
   c_register_builtin_type.  */
static GTY(()) tree registered_builtin_types;

/* Return a data type that has machine mode MODE.
   If the mode is an integer,
   then UNSIGNEDP selects between signed and unsigned types.
   If the mode is a fixed-point mode,
   then UNSIGNEDP selects between saturating and nonsaturating types.  */

tree
c_common_type_for_mode (enum machine_mode mode, int unsignedp)
{
  tree t;

  if (mode == TYPE_MODE (integer_type_node))
    return unsignedp ? unsigned_type_node : integer_type_node;

  if (mode == TYPE_MODE (signed_char_type_node))
    return unsignedp ? unsigned_char_type_node : signed_char_type_node;

  if (mode == TYPE_MODE (short_integer_type_node))
    return unsignedp ? short_unsigned_type_node : short_integer_type_node;

  if (mode == TYPE_MODE (long_integer_type_node))
    return unsignedp ? long_unsigned_type_node : long_integer_type_node;

  if (mode == TYPE_MODE (long_long_integer_type_node))
    return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;

  if (mode == TYPE_MODE (widest_integer_literal_type_node))
    return unsignedp ? widest_unsigned_literal_type_node
		     : widest_integer_literal_type_node;

  if (mode == QImode)
    return unsignedp ? unsigned_intQI_type_node : intQI_type_node;

  if (mode == HImode)
    return unsignedp ? unsigned_intHI_type_node : intHI_type_node;

  if (mode == SImode)
    return unsignedp ? unsigned_intSI_type_node : intSI_type_node;

  if (mode == DImode)
    return unsignedp ? unsigned_intDI_type_node : intDI_type_node;

#if HOST_BITS_PER_WIDE_INT >= 64
  if (mode == TYPE_MODE (intTI_type_node))
    return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
#endif

  if (mode == TYPE_MODE (float_type_node))
    return float_type_node;

  if (mode == TYPE_MODE (double_type_node))
    return double_type_node;

  if (mode == TYPE_MODE (long_double_type_node))
    return long_double_type_node;

  if (mode == TYPE_MODE (void_type_node))
    return void_type_node;

  if (mode == TYPE_MODE (build_pointer_type (char_type_node)))
    return (unsignedp
	    ? make_unsigned_type (GET_MODE_PRECISION (mode))
	    : make_signed_type (GET_MODE_PRECISION (mode)));

  if (mode == TYPE_MODE (build_pointer_type (integer_type_node)))
    return (unsignedp
	    ? make_unsigned_type (GET_MODE_PRECISION (mode))
	    : make_signed_type (GET_MODE_PRECISION (mode)));

  if (COMPLEX_MODE_P (mode))
    {
      enum machine_mode inner_mode;
      tree inner_type;

      if (mode == TYPE_MODE (complex_float_type_node))
	return complex_float_type_node;
      if (mode == TYPE_MODE (complex_double_type_node))
	return complex_double_type_node;
      if (mode == TYPE_MODE (complex_long_double_type_node))
	return complex_long_double_type_node;

      if (mode == TYPE_MODE (complex_integer_type_node) && !unsignedp)
	return complex_integer_type_node;

      inner_mode = GET_MODE_INNER (mode);
      inner_type = c_common_type_for_mode (inner_mode, unsignedp);
      if (inner_type != NULL_TREE)
	return build_complex_type (inner_type);
    }
  else if (VECTOR_MODE_P (mode))
    {
      enum machine_mode inner_mode = GET_MODE_INNER (mode);
      tree inner_type = c_common_type_for_mode (inner_mode, unsignedp);
      if (inner_type != NULL_TREE)
	return build_vector_type_for_mode (inner_type, mode);
    }

  if (mode == TYPE_MODE (dfloat32_type_node))
    return dfloat32_type_node;
  if (mode == TYPE_MODE (dfloat64_type_node))
    return dfloat64_type_node;
  if (mode == TYPE_MODE (dfloat128_type_node))
    return dfloat128_type_node;

  if (ALL_SCALAR_FIXED_POINT_MODE_P (mode))
    {
      if (mode == TYPE_MODE (short_fract_type_node))
	return unsignedp ? sat_short_fract_type_node : short_fract_type_node;
      if (mode == TYPE_MODE (fract_type_node))
	return unsignedp ? sat_fract_type_node : fract_type_node;
      if (mode == TYPE_MODE (long_fract_type_node))
	return unsignedp ? sat_long_fract_type_node : long_fract_type_node;
      if (mode == TYPE_MODE (long_long_fract_type_node))
	return unsignedp ? sat_long_long_fract_type_node
			 : long_long_fract_type_node;

      if (mode == TYPE_MODE (unsigned_short_fract_type_node))
	return unsignedp ? sat_unsigned_short_fract_type_node
			 : unsigned_short_fract_type_node;
      if (mode == TYPE_MODE (unsigned_fract_type_node))
	return unsignedp ? sat_unsigned_fract_type_node
			 : unsigned_fract_type_node;
      if (mode == TYPE_MODE (unsigned_long_fract_type_node))
	return unsignedp ? sat_unsigned_long_fract_type_node
			 : unsigned_long_fract_type_node;
      if (mode == TYPE_MODE (unsigned_long_long_fract_type_node))
	return unsignedp ? sat_unsigned_long_long_fract_type_node
			 : unsigned_long_long_fract_type_node;

      if (mode == TYPE_MODE (short_accum_type_node))
	return unsignedp ? sat_short_accum_type_node : short_accum_type_node;
      if (mode == TYPE_MODE (accum_type_node))
	return unsignedp ? sat_accum_type_node : accum_type_node;
      if (mode == TYPE_MODE (long_accum_type_node))
	return unsignedp ? sat_long_accum_type_node : long_accum_type_node;
      if (mode == TYPE_MODE (long_long_accum_type_node))
	return unsignedp ? sat_long_long_accum_type_node
			 : long_long_accum_type_node;

      if (mode == TYPE_MODE (unsigned_short_accum_type_node))
	return unsignedp ? sat_unsigned_short_accum_type_node
			 : unsigned_short_accum_type_node;
      if (mode == TYPE_MODE (unsigned_accum_type_node))
	return unsignedp ? sat_unsigned_accum_type_node
			 : unsigned_accum_type_node;
      if (mode == TYPE_MODE (unsigned_long_accum_type_node))
	return unsignedp ? sat_unsigned_long_accum_type_node
			 : unsigned_long_accum_type_node;
      if (mode == TYPE_MODE (unsigned_long_long_accum_type_node))
	return unsignedp ? sat_unsigned_long_long_accum_type_node
			 : unsigned_long_long_accum_type_node;

      if (mode == QQmode)
	return unsignedp ? sat_qq_type_node : qq_type_node;
      if (mode == HQmode)
	return unsignedp ? sat_hq_type_node : hq_type_node;
      if (mode == SQmode)
	return unsignedp ? sat_sq_type_node : sq_type_node;
      if (mode == DQmode)
	return unsignedp ? sat_dq_type_node : dq_type_node;
      if (mode == TQmode)
	return unsignedp ? sat_tq_type_node : tq_type_node;

      if (mode == UQQmode)
	return unsignedp ? sat_uqq_type_node : uqq_type_node;
      if (mode == UHQmode)
	return unsignedp ? sat_uhq_type_node : uhq_type_node;
      if (mode == USQmode)
	return unsignedp ? sat_usq_type_node : usq_type_node;
      if (mode == UDQmode)
	return unsignedp ? sat_udq_type_node : udq_type_node;
      if (mode == UTQmode)
	return unsignedp ? sat_utq_type_node : utq_type_node;

      if (mode == HAmode)
	return unsignedp ? sat_ha_type_node : ha_type_node;
      if (mode == SAmode)
	return unsignedp ? sat_sa_type_node : sa_type_node;
      if (mode == DAmode)
	return unsignedp ? sat_da_type_node : da_type_node;
      if (mode == TAmode)
	return unsignedp ? sat_ta_type_node : ta_type_node;

      if (mode == UHAmode)
	return unsignedp ? sat_uha_type_node : uha_type_node;
      if (mode == USAmode)
	return unsignedp ? sat_usa_type_node : usa_type_node;
      if (mode == UDAmode)
	return unsignedp ? sat_uda_type_node : uda_type_node;
      if (mode == UTAmode)
	return unsignedp ? sat_uta_type_node : uta_type_node;
    }

  for (t = registered_builtin_types; t; t = TREE_CHAIN (t))
    if (TYPE_MODE (TREE_VALUE (t)) == mode)
      return TREE_VALUE (t);

  return 0;
}

tree
c_common_unsigned_type (tree type)
{
  return c_common_signed_or_unsigned_type (1, type);
}

/* Return a signed type the same as TYPE in other respects.  */

tree
c_common_signed_type (tree type)
{
  return c_common_signed_or_unsigned_type (0, type);
}

/* Return a type the same as TYPE except unsigned or
   signed according to UNSIGNEDP.  */

tree
c_common_signed_or_unsigned_type (int unsignedp, tree type)
{
  tree type1;

  /* This block of code emulates the behavior of the old
     c_common_unsigned_type. In particular, it returns
     long_unsigned_type_node if passed a long, even when a int would
     have the same size. This is necessary for warnings to work
     correctly in archs where sizeof(int) == sizeof(long) */

  type1 = TYPE_MAIN_VARIANT (type);
  if (type1 == signed_char_type_node || type1 == char_type_node || type1 == unsigned_char_type_node)
    return unsignedp ? unsigned_char_type_node : signed_char_type_node;
  if (type1 == integer_type_node || type1 == unsigned_type_node)
    return unsignedp ? unsigned_type_node : integer_type_node;
  if (type1 == short_integer_type_node || type1 == short_unsigned_type_node)
    return unsignedp ? short_unsigned_type_node : short_integer_type_node;
  if (type1 == long_integer_type_node || type1 == long_unsigned_type_node)
    return unsignedp ? long_unsigned_type_node : long_integer_type_node;
  if (type1 == long_long_integer_type_node || type1 == long_long_unsigned_type_node)
    return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
  if (type1 == widest_integer_literal_type_node || type1 == widest_unsigned_literal_type_node)
    return unsignedp ? widest_unsigned_literal_type_node : widest_integer_literal_type_node;
#if HOST_BITS_PER_WIDE_INT >= 64
  if (type1 == intTI_type_node || type1 == unsigned_intTI_type_node)
    return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
#endif
  if (type1 == intDI_type_node || type1 == unsigned_intDI_type_node)
    return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
  if (type1 == intSI_type_node || type1 == unsigned_intSI_type_node)
    return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
  if (type1 == intHI_type_node || type1 == unsigned_intHI_type_node)
    return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
  if (type1 == intQI_type_node || type1 == unsigned_intQI_type_node)
    return unsignedp ? unsigned_intQI_type_node : intQI_type_node;

#define C_COMMON_FIXED_TYPES(NAME)	    \
  if (type1 == short_ ## NAME ## _type_node \
      || type1 == unsigned_short_ ## NAME ## _type_node) \
    return unsignedp ? unsigned_short_ ## NAME ## _type_node \
		     : short_ ## NAME ## _type_node; \
  if (type1 == NAME ## _type_node \
      || type1 == unsigned_ ## NAME ## _type_node) \
    return unsignedp ? unsigned_ ## NAME ## _type_node \
		     : NAME ## _type_node; \
  if (type1 == long_ ## NAME ## _type_node \
      || type1 == unsigned_long_ ## NAME ## _type_node) \
    return unsignedp ? unsigned_long_ ## NAME ## _type_node \
		     : long_ ## NAME ## _type_node; \
  if (type1 == long_long_ ## NAME ## _type_node \
      || type1 == unsigned_long_long_ ## NAME ## _type_node) \
    return unsignedp ? unsigned_long_long_ ## NAME ## _type_node \
		     : long_long_ ## NAME ## _type_node;

#define C_COMMON_FIXED_MODE_TYPES(NAME) \
  if (type1 == NAME ## _type_node \
      || type1 == u ## NAME ## _type_node) \
    return unsignedp ? u ## NAME ## _type_node \
		     : NAME ## _type_node;

#define C_COMMON_FIXED_TYPES_SAT(NAME) \
  if (type1 == sat_ ## short_ ## NAME ## _type_node \
      || type1 == sat_ ## unsigned_short_ ## NAME ## _type_node) \
    return unsignedp ? sat_ ## unsigned_short_ ## NAME ## _type_node \
		     : sat_ ## short_ ## NAME ## _type_node; \
  if (type1 == sat_ ## NAME ## _type_node \
      || type1 == sat_ ## unsigned_ ## NAME ## _type_node) \
    return unsignedp ? sat_ ## unsigned_ ## NAME ## _type_node \
		     : sat_ ## NAME ## _type_node; \
  if (type1 == sat_ ## long_ ## NAME ## _type_node \
      || type1 == sat_ ## unsigned_long_ ## NAME ## _type_node) \
    return unsignedp ? sat_ ## unsigned_long_ ## NAME ## _type_node \
		     : sat_ ## long_ ## NAME ## _type_node; \
  if (type1 == sat_ ## long_long_ ## NAME ## _type_node \
      || type1 == sat_ ## unsigned_long_long_ ## NAME ## _type_node) \
    return unsignedp ? sat_ ## unsigned_long_long_ ## NAME ## _type_node \
		     : sat_ ## long_long_ ## NAME ## _type_node;

#define C_COMMON_FIXED_MODE_TYPES_SAT(NAME)	\
  if (type1 == sat_ ## NAME ## _type_node \
      || type1 == sat_ ## u ## NAME ## _type_node) \
    return unsignedp ? sat_ ## u ## NAME ## _type_node \
		     : sat_ ## NAME ## _type_node;

  C_COMMON_FIXED_TYPES (fract);
  C_COMMON_FIXED_TYPES_SAT (fract);
  C_COMMON_FIXED_TYPES (accum);
  C_COMMON_FIXED_TYPES_SAT (accum);

  C_COMMON_FIXED_MODE_TYPES (qq);
  C_COMMON_FIXED_MODE_TYPES (hq);
  C_COMMON_FIXED_MODE_TYPES (sq);
  C_COMMON_FIXED_MODE_TYPES (dq);
  C_COMMON_FIXED_MODE_TYPES (tq);
  C_COMMON_FIXED_MODE_TYPES_SAT (qq);
  C_COMMON_FIXED_MODE_TYPES_SAT (hq);
  C_COMMON_FIXED_MODE_TYPES_SAT (sq);
  C_COMMON_FIXED_MODE_TYPES_SAT (dq);
  C_COMMON_FIXED_MODE_TYPES_SAT (tq);
  C_COMMON_FIXED_MODE_TYPES (ha);
  C_COMMON_FIXED_MODE_TYPES (sa);
  C_COMMON_FIXED_MODE_TYPES (da);
  C_COMMON_FIXED_MODE_TYPES (ta);
  C_COMMON_FIXED_MODE_TYPES_SAT (ha);
  C_COMMON_FIXED_MODE_TYPES_SAT (sa);
  C_COMMON_FIXED_MODE_TYPES_SAT (da);
  C_COMMON_FIXED_MODE_TYPES_SAT (ta);

  /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
     the precision; they have precision set to match their range, but
     may use a wider mode to match an ABI.  If we change modes, we may
     wind up with bad conversions.  For INTEGER_TYPEs in C, must check
     the precision as well, so as to yield correct results for
     bit-field types.  C++ does not have these separate bit-field
     types, and producing a signed or unsigned variant of an
     ENUMERAL_TYPE may cause other problems as well.  */

  if (!INTEGRAL_TYPE_P (type)
      || TYPE_UNSIGNED (type) == unsignedp)
    return type;

#define TYPE_OK(node)							    \
  (TYPE_MODE (type) == TYPE_MODE (node)					    \
   && TYPE_PRECISION (type) == TYPE_PRECISION (node))
  if (TYPE_OK (signed_char_type_node))
    return unsignedp ? unsigned_char_type_node : signed_char_type_node;
  if (TYPE_OK (integer_type_node))
    return unsignedp ? unsigned_type_node : integer_type_node;
  if (TYPE_OK (short_integer_type_node))
    return unsignedp ? short_unsigned_type_node : short_integer_type_node;
  if (TYPE_OK (long_integer_type_node))
    return unsignedp ? long_unsigned_type_node : long_integer_type_node;
  if (TYPE_OK (long_long_integer_type_node))
    return (unsignedp ? long_long_unsigned_type_node
	    : long_long_integer_type_node);
  if (TYPE_OK (widest_integer_literal_type_node))
    return (unsignedp ? widest_unsigned_literal_type_node
	    : widest_integer_literal_type_node);

#if HOST_BITS_PER_WIDE_INT >= 64
  if (TYPE_OK (intTI_type_node))
    return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
#endif
  if (TYPE_OK (intDI_type_node))
    return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
  if (TYPE_OK (intSI_type_node))
    return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
  if (TYPE_OK (intHI_type_node))
    return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
  if (TYPE_OK (intQI_type_node))
    return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
#undef TYPE_OK

  return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
}

/* Build a bit-field integer type for the given WIDTH and UNSIGNEDP.  */

tree
c_build_bitfield_integer_type (unsigned HOST_WIDE_INT width, int unsignedp)
{
  /* Extended integer types of the same width as a standard type have
     lesser rank, so those of the same width as int promote to int or
     unsigned int and are valid for printf formats expecting int or
     unsigned int.  To avoid such special cases, avoid creating
     extended integer types for bit-fields if a standard integer type
     is available.  */
  if (width == TYPE_PRECISION (integer_type_node))
    return unsignedp ? unsigned_type_node : integer_type_node;
  if (width == TYPE_PRECISION (signed_char_type_node))
    return unsignedp ? unsigned_char_type_node : signed_char_type_node;
  if (width == TYPE_PRECISION (short_integer_type_node))
    return unsignedp ? short_unsigned_type_node : short_integer_type_node;
  if (width == TYPE_PRECISION (long_integer_type_node))
    return unsignedp ? long_unsigned_type_node : long_integer_type_node;
  if (width == TYPE_PRECISION (long_long_integer_type_node))
    return (unsignedp ? long_long_unsigned_type_node
	    : long_long_integer_type_node);
  return build_nonstandard_integer_type (width, unsignedp);
}

/* The C version of the register_builtin_type langhook.  */

void
c_register_builtin_type (tree type, const char* name)
{
  tree decl;

  decl = build_decl (TYPE_DECL, get_identifier (name), type);
  DECL_ARTIFICIAL (decl) = 1;
  if (!TYPE_NAME (type))
    TYPE_NAME (type) = decl;
  pushdecl (decl);

  registered_builtin_types = tree_cons (0, type, registered_builtin_types);
}

/* Print an error message for invalid operands to arith operation
   CODE with TYPE0 for operand 0, and TYPE1 for operand 1.
   LOCATION is the location of the message.  */

void
binary_op_error (location_t location, enum tree_code code,
		 tree type0, tree type1)
{
  const char *opname;

  switch (code)
    {
    case PLUS_EXPR:
      opname = "+"; break;
    case MINUS_EXPR:
      opname = "-"; break;
    case MULT_EXPR:
      opname = "*"; break;
    case MAX_EXPR:
      opname = "max"; break;
    case MIN_EXPR:
      opname = "min"; break;
    case EQ_EXPR:
      opname = "=="; break;
    case NE_EXPR:
      opname = "!="; break;
    case LE_EXPR:
      opname = "<="; break;
    case GE_EXPR:
      opname = ">="; break;
    case LT_EXPR:
      opname = "<"; break;
    case GT_EXPR:
      opname = ">"; break;
    case LSHIFT_EXPR:
      opname = "<<"; break;
    case RSHIFT_EXPR:
      opname = ">>"; break;
    case TRUNC_MOD_EXPR:
    case FLOOR_MOD_EXPR:
      opname = "%"; break;
    case TRUNC_DIV_EXPR:
    case FLOOR_DIV_EXPR:
      opname = "/"; break;
    case BIT_AND_EXPR:
      opname = "&"; break;
    case BIT_IOR_EXPR:
      opname = "|"; break;
    case TRUTH_ANDIF_EXPR:
      opname = "&&"; break;
    case TRUTH_ORIF_EXPR:
      opname = "||"; break;
    case BIT_XOR_EXPR:
      opname = "^"; break;
    default:
      gcc_unreachable ();
    }
  error_at (location,
	    "invalid operands to binary %s (have %qT and %qT)", opname,
	    type0, type1);
}

/* Subroutine of build_binary_op, used for comparison operations.
   See if the operands have both been converted from subword integer types
   and, if so, perhaps change them both back to their original type.
   This function is also responsible for converting the two operands
   to the proper common type for comparison.

   The arguments of this function are all pointers to local variables
   of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1,
   RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE.

   If this function returns nonzero, it means that the comparison has
   a constant value.  What this function returns is an expression for
   that value.  */

tree
shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr,
		 enum tree_code *rescode_ptr)
{
  tree type;
  tree op0 = *op0_ptr;
  tree op1 = *op1_ptr;
  int unsignedp0, unsignedp1;
  int real1, real2;
  tree primop0, primop1;
  enum tree_code code = *rescode_ptr;

  /* Throw away any conversions to wider types
     already present in the operands.  */

  primop0 = get_narrower (op0, &unsignedp0);
  primop1 = get_narrower (op1, &unsignedp1);

  /* Handle the case that OP0 does not *contain* a conversion
     but it *requires* conversion to FINAL_TYPE.  */

  if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr)
    unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (op0));
  if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr)
    unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (op1));

  /* If one of the operands must be floated, we cannot optimize.  */
  real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE;
  real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE;

  /* If first arg is constant, swap the args (changing operation
     so value is preserved), for canonicalization.  Don't do this if
     the second arg is 0.  */

  if (TREE_CONSTANT (primop0)
      && !integer_zerop (primop1) && !real_zerop (primop1)
      && !fixed_zerop (primop1))
    {
      tree tem = primop0;
      int temi = unsignedp0;
      primop0 = primop1;
      primop1 = tem;
      tem = op0;
      op0 = op1;
      op1 = tem;
      *op0_ptr = op0;
      *op1_ptr = op1;
      unsignedp0 = unsignedp1;
      unsignedp1 = temi;
      temi = real1;
      real1 = real2;
      real2 = temi;

      switch (code)
	{
	case LT_EXPR:
	  code = GT_EXPR;
	  break;
	case GT_EXPR:
	  code = LT_EXPR;
	  break;
	case LE_EXPR:
	  code = GE_EXPR;
	  break;
	case GE_EXPR:
	  code = LE_EXPR;
	  break;
	default:
	  break;
	}
      *rescode_ptr = code;
    }

  /* If comparing an integer against a constant more bits wide,
     maybe we can deduce a value of 1 or 0 independent of the data.
     Or else truncate the constant now
     rather than extend the variable at run time.

     This is only interesting if the constant is the wider arg.
     Also, it is not safe if the constant is unsigned and the
     variable arg is signed, since in this case the variable
     would be sign-extended and then regarded as unsigned.
     Our technique fails in this case because the lowest/highest
     possible unsigned results don't follow naturally from the
     lowest/highest possible values of the variable operand.
     For just EQ_EXPR and NE_EXPR there is another technique that
     could be used: see if the constant can be faithfully represented
     in the other operand's type, by truncating it and reextending it
     and see if that preserves the constant's value.  */

  if (!real1 && !real2
      && TREE_CODE (TREE_TYPE (primop0)) != FIXED_POINT_TYPE
      && TREE_CODE (primop1) == INTEGER_CST
      && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr))
    {
      int min_gt, max_gt, min_lt, max_lt;
      tree maxval, minval;
      /* 1 if comparison is nominally unsigned.  */
      int unsignedp = TYPE_UNSIGNED (*restype_ptr);
      tree val;

      type = c_common_signed_or_unsigned_type (unsignedp0,
					       TREE_TYPE (primop0));

      maxval = TYPE_MAX_VALUE (type);
      minval = TYPE_MIN_VALUE (type);

      if (unsignedp && !unsignedp0)
	*restype_ptr = c_common_signed_type (*restype_ptr);

      if (TREE_TYPE (primop1) != *restype_ptr)
	{
	  /* Convert primop1 to target type, but do not introduce
	     additional overflow.  We know primop1 is an int_cst.  */
	  primop1 = force_fit_type_double (*restype_ptr,
					   TREE_INT_CST_LOW (primop1),
					   TREE_INT_CST_HIGH (primop1), 0,
					   TREE_OVERFLOW (primop1));
	}
      if (type != *restype_ptr)
	{
	  minval = convert (*restype_ptr, minval);
	  maxval = convert (*restype_ptr, maxval);
	}

      if (unsignedp && unsignedp0)
	{
	  min_gt = INT_CST_LT_UNSIGNED (primop1, minval);
	  max_gt = INT_CST_LT_UNSIGNED (primop1, maxval);
	  min_lt = INT_CST_LT_UNSIGNED (minval, primop1);
	  max_lt = INT_CST_LT_UNSIGNED (maxval, primop1);
	}
      else
	{
	  min_gt = INT_CST_LT (primop1, minval);
	  max_gt = INT_CST_LT (primop1, maxval);
	  min_lt = INT_CST_LT (minval, primop1);
	  max_lt = INT_CST_LT (maxval, primop1);
	}

      val = 0;
      /* This used to be a switch, but Genix compiler can't handle that.  */
      if (code == NE_EXPR)
	{
	  if (max_lt || min_gt)
	    val = truthvalue_true_node;
	}
      else if (code == EQ_EXPR)
	{
	  if (max_lt || min_gt)
	    val = truthvalue_false_node;
	}
      else if (code == LT_EXPR)
	{
	  if (max_lt)
	    val = truthvalue_true_node;
	  if (!min_lt)
	    val = truthvalue_false_node;
	}
      else if (code == GT_EXPR)
	{
	  if (min_gt)
	    val = truthvalue_true_node;
	  if (!max_gt)
	    val = truthvalue_false_node;
	}
      else if (code == LE_EXPR)
	{
	  if (!max_gt)
	    val = truthvalue_true_node;
	  if (min_gt)
	    val = truthvalue_false_node;
	}
      else if (code == GE_EXPR)
	{
	  if (!min_lt)
	    val = truthvalue_true_node