gcc/c-family/c-common.cc

/* Subroutines shared by all languages that are variants of C.
   Copyright (C) 1992-2022 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/>.  */

#define GCC_C_COMMON_C

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "target.h"
#include "function.h"
#include "tree.h"
#include "memmodel.h"
#include "c-common.h"
#include "gimple-expr.h"
#include "tm_p.h"
#include "stringpool.h"
#include "cgraph.h"
#include "diagnostic.h"
#include "intl.h"
#include "stor-layout.h"
#include "calls.h"
#include "attribs.h"
#include "varasm.h"
#include "trans-mem.h"
#include "c-objc.h"
#include "common/common-target.h"
#include "langhooks.h"
#include "tree-inline.h"
#include "toplev.h"
#include "tree-iterator.h"
#include "opts.h"
#include "gimplify.h"
#include "substring-locations.h"
#include "spellcheck.h"
#include "c-spellcheck.h"
#include "selftest.h"
#include "debug.h"
#include "tree-vector-builder.h"
#include "vec-perm-indices.h"

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

/* Mode used to build pointers (VOIDmode means ptr_mode).  */

machine_mode c_default_pointer_mode = VOIDmode;

/* 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 char8_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 `wchar_t[SOMENUMBER]' or something like it.
   Used when a wide string literal is created.

	tree wchar_array_type_node;

   Type `char8_t[SOMENUMBER]' or something like it.
   Used when a UTF-8 string literal is created.

	tree char8_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 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;

/* 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 (or C11) dialect of C.  */

int flag_isoc99;

/* Nonzero means use the ISO C11 dialect of C.  */

int flag_isoc11;

/* Nonzero means use the ISO C2X dialect of C.  */

int flag_isoc2x;

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

int flag_hosted = 1;


/* ObjC language option variables.  */


/* 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.  */

/* The reference version of the ABI for -Wabi.  */

int warn_abi_version = -1;

/* The C++ dialect being used.  Default set in c_common_post_options.  */

enum cxx_dialect cxx_dialect = cxx_unset;

/* Maximum template instantiation depth.  This limit exists to limit the
   time it takes to notice excessively recursive template instantiations.

   The default is lower than the 1024 recommended by the C++0x standard
   because G++ runs out of stack before 1024 with highly recursive template
   argument deduction substitution (g++.dg/cpp0x/enum11.C).  */

int max_tinst_depth = 900;

/* 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) (location_t, tree, int);

/* Nonzero means don't warn about problems that occur when the code is
   executed.  */
int c_inhibit_evaluation_warnings;

/* Whether we are building a boolean conversion inside
   convert_for_assignment, or some other late binary operation.  If
   build_binary_op is called for C (from code shared by C and C++) in
   this case, then the operands have already been folded and the
   result will not be folded again, so C_MAYBE_CONST_EXPR should not
   be generated.  */
bool in_late_binary_op;

/* Whether lexing has been completed, so subsequent preprocessor
   errors should use the compiler's input_location.  */
bool done_lexing = false;

/* 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},
};

/* Global visibility options.  */
struct visibility_flags visibility_options;

static tree check_case_value (location_t, tree);


static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);

/* 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=c++98: D_CONLY | D_CXX11 | D_CXX20 | D_OBJC
   C++ --std=c++11: D_CONLY | D_CXX20 | D_OBJC
   C++ --std=c++20: 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.

   Note the complication of the D_CXX_OBJC keywords.  These are
   reserved words such as 'class'.  In C++, 'class' is a reserved
   word.  In Objective-C++ it is too.  In Objective-C, it is a
   reserved word too, but only if it follows an '@' sign.
*/
const struct c_common_resword c_common_reswords[] =
{
  { "_Alignas",		RID_ALIGNAS,   D_CONLY },
  { "_Alignof",		RID_ALIGNOF,   D_CONLY },
  { "_Atomic",		RID_ATOMIC,    D_CONLY },
  { "_Bool",		RID_BOOL,      D_CONLY },
  { "_Complex",		RID_COMPLEX,	0 },
  { "_Imaginary",	RID_IMAGINARY, D_CONLY },
  { "_Float16",         RID_FLOAT16,   D_CONLY },
  { "_Float32",         RID_FLOAT32,   D_CONLY },
  { "_Float64",         RID_FLOAT64,   D_CONLY },
  { "_Float128",        RID_FLOAT128,  D_CONLY },
  { "_Float32x",        RID_FLOAT32X,  D_CONLY },
  { "_Float64x",        RID_FLOAT64X,  D_CONLY },
  { "_Float128x",       RID_FLOAT128X, D_CONLY },
  { "_Decimal32",       RID_DFLOAT32,  D_CONLY },
  { "_Decimal64",       RID_DFLOAT64,  D_CONLY },
  { "_Decimal128",      RID_DFLOAT128, D_CONLY },
  { "_Fract",           RID_FRACT,     D_CONLY | D_EXT },
  { "_Accum",           RID_ACCUM,     D_CONLY | D_EXT },
  { "_Sat",             RID_SAT,       D_CONLY | D_EXT },
  { "_Static_assert",   RID_STATIC_ASSERT, D_CONLY },
  { "_Noreturn",        RID_NORETURN,  D_CONLY },
  { "_Generic",         RID_GENERIC,   D_CONLY },
  { "_Thread_local",    RID_THREAD,    D_CONLY },
  { "__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 },
  { "__auto_type",	RID_AUTO_TYPE,	D_CONLY },
  { "__bases",          RID_BASES, D_CXXONLY },
  { "__builtin_addressof", RID_ADDRESSOF, D_CXXONLY },
  { "__builtin_bit_cast", RID_BUILTIN_BIT_CAST, D_CXXONLY },
  { "__builtin_call_with_static_chain",
    RID_BUILTIN_CALL_WITH_STATIC_CHAIN, D_CONLY },
  { "__builtin_choose_expr", RID_CHOOSE_EXPR, D_CONLY },
  { "__builtin_complex", RID_BUILTIN_COMPLEX, D_CONLY },
  { "__builtin_convertvector", RID_BUILTIN_CONVERTVECTOR, 0 },
  { "__builtin_has_attribute", RID_BUILTIN_HAS_ATTRIBUTE, 0 },
  { "__builtin_launder", RID_BUILTIN_LAUNDER, D_CXXONLY },
  { "__builtin_assoc_barrier", RID_BUILTIN_ASSOC_BARRIER, 0 },
  { "__builtin_shuffle", RID_BUILTIN_SHUFFLE, 0 },
  { "__builtin_shufflevector", RID_BUILTIN_SHUFFLEVECTOR, 0 },
  { "__builtin_tgmath", RID_BUILTIN_TGMATH, 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 },
  { "__constinit",	RID_CONSTINIT,	D_CXXONLY },
  { "__decltype",       RID_DECLTYPE,   D_CXXONLY },
  { "__direct_bases",   RID_DIRECT_BASES, 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_unique_object_representations", RID_HAS_UNIQUE_OBJ_REPRESENTATIONS,
					D_CXXONLY },
  { "__has_virtual_destructor", RID_HAS_VIRTUAL_DESTRUCTOR, D_CXXONLY },
  { "__imag",		RID_IMAGPART,	0 },
  { "__imag__",		RID_IMAGPART,	0 },
  { "__inline",		RID_INLINE,	0 },
  { "__inline__",	RID_INLINE,	0 },
  { "__is_abstract",	RID_IS_ABSTRACT, D_CXXONLY },
  { "__is_aggregate",	RID_IS_AGGREGATE, D_CXXONLY },
  { "__is_base_of",	RID_IS_BASE_OF, D_CXXONLY },
  { "__is_class",	RID_IS_CLASS,	D_CXXONLY },
  { "__is_empty",	RID_IS_EMPTY,	D_CXXONLY },
  { "__is_enum",	RID_IS_ENUM,	D_CXXONLY },
  { "__is_final",	RID_IS_FINAL,	D_CXXONLY },
  { "__is_layout_compatible", RID_IS_LAYOUT_COMPATIBLE, D_CXXONLY },
  { "__is_literal_type", RID_IS_LITERAL_TYPE, D_CXXONLY },
  { "__is_pointer_interconvertible_base_of",
			RID_IS_POINTER_INTERCONVERTIBLE_BASE_OF, D_CXXONLY },
  { "__is_pod",		RID_IS_POD,	D_CXXONLY },
  { "__is_polymorphic",	RID_IS_POLYMORPHIC, D_CXXONLY },
  { "__is_same",     RID_IS_SAME_AS, D_CXXONLY },
  { "__is_same_as",     RID_IS_SAME_AS, D_CXXONLY },
  { "__is_standard_layout", RID_IS_STD_LAYOUT, D_CXXONLY },
  { "__is_trivial",     RID_IS_TRIVIAL, D_CXXONLY },
  { "__is_trivially_assignable", RID_IS_TRIVIALLY_ASSIGNABLE, D_CXXONLY },
  { "__is_trivially_constructible", RID_IS_TRIVIALLY_CONSTRUCTIBLE, D_CXXONLY },
  { "__is_trivially_copyable", RID_IS_TRIVIALLY_COPYABLE, D_CXXONLY },
  { "__is_union",	RID_IS_UNION,	D_CXXONLY },
  { "__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 },
  { "__transaction_atomic", RID_TRANSACTION_ATOMIC, 0 },
  { "__transaction_relaxed", RID_TRANSACTION_RELAXED, 0 },
  { "__transaction_cancel", RID_TRANSACTION_CANCEL, 0 },
  { "__typeof",		RID_TYPEOF,	0 },
  { "__typeof__",	RID_TYPEOF,	0 },
  { "__underlying_type", RID_UNDERLYING_TYPE, D_CXXONLY },
  { "__volatile",	RID_VOLATILE,	0 },
  { "__volatile__",	RID_VOLATILE,	0 },
  { "__GIMPLE",		RID_GIMPLE,	D_CONLY },
  { "__PHI",		RID_PHI,	D_CONLY },
  { "__RTL",		RID_RTL,	D_CONLY },
  { "alignas",		RID_ALIGNAS,	D_CXXONLY | D_CXX11 | D_CXXWARN },
  { "alignof",		RID_ALIGNOF,	D_CXXONLY | D_CXX11 | D_CXXWARN },
  { "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 },
  { "char8_t",		RID_CHAR8,	D_CXX_CHAR8_T_FLAGS | D_CXXWARN },
  { "char16_t",		RID_CHAR16,	D_CXXONLY | D_CXX11 | D_CXXWARN },
  { "char32_t",		RID_CHAR32,	D_CXXONLY | D_CXX11 | D_CXXWARN },
  { "class",		RID_CLASS,	D_CXX_OBJC | D_CXXWARN },
  { "const",		RID_CONST,	0 },
  { "consteval",	RID_CONSTEVAL,	D_CXXONLY | D_CXX20 | D_CXXWARN },
  { "constexpr",	RID_CONSTEXPR,	D_CXXONLY | D_CXX11 | D_CXXWARN },
  { "constinit",	RID_CONSTINIT,	D_CXXONLY | D_CXX20 | D_CXXWARN },
  { "const_cast",	RID_CONSTCAST,	D_CXXONLY | D_CXXWARN },
  { "continue",		RID_CONTINUE,	0 },
  { "decltype",         RID_DECLTYPE,   D_CXXONLY | D_CXX11 | 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 },
  { "noexcept",		RID_NOEXCEPT,	D_CXXONLY | D_CXX11 | D_CXXWARN },
  { "nullptr",		RID_NULLPTR,	D_CXXONLY | D_CXX11 | 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_CXX11 | 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 },
  { "thread_local",	RID_THREAD,	D_CXXONLY | D_CXX11 | 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 },
  { "__is_assignable", RID_IS_ASSIGNABLE, D_CXXONLY },
  { "__is_constructible", RID_IS_CONSTRUCTIBLE, D_CXXONLY },
  { "__is_nothrow_assignable", RID_IS_NOTHROW_ASSIGNABLE, D_CXXONLY },
  { "__is_nothrow_constructible", RID_IS_NOTHROW_CONSTRUCTIBLE, D_CXXONLY },

  /* C++ transactional memory.  */
  { "synchronized",	RID_SYNCHRONIZED, D_CXX_OBJC | D_TRANSMEM },
  { "atomic_noexcept",	RID_ATOMIC_NOEXCEPT, D_CXXONLY | D_TRANSMEM },
  { "atomic_cancel",	RID_ATOMIC_CANCEL, D_CXXONLY | D_TRANSMEM },
  { "atomic_commit",	RID_TRANSACTION_ATOMIC, D_CXXONLY | D_TRANSMEM },

  /* Concepts-related keywords */
  { "concept",		RID_CONCEPT,	D_CXX_CONCEPTS_FLAGS | D_CXXWARN },
  { "requires", 	RID_REQUIRES,	D_CXX_CONCEPTS_FLAGS | D_CXXWARN },

  /* Modules-related keywords, these are internal unspellable tokens,
     created by the preprocessor.  */
  { "module ",		RID__MODULE,	D_CXX_MODULES_FLAGS | D_CXXWARN },
  { "import ",		RID__IMPORT,	D_CXX_MODULES_FLAGS | D_CXXWARN },
  { "export ",		RID__EXPORT,	D_CXX_MODULES_FLAGS | D_CXXWARN },

  /* Coroutines-related keywords */
  { "co_await",		RID_CO_AWAIT,	D_CXX_COROUTINES_FLAGS | D_CXXWARN },
  { "co_yield",		RID_CO_YIELD,	D_CXX_COROUTINES_FLAGS | D_CXXWARN },
  { "co_return", 	RID_CO_RETURN,	D_CXX_COROUTINES_FLAGS | D_CXXWARN },

  /* 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 },
  { "optional",		RID_AT_OPTIONAL,	D_OBJC },
  { "required",		RID_AT_REQUIRED,	D_OBJC },
  { "property",		RID_AT_PROPERTY,	D_OBJC },
  { "package",		RID_AT_PACKAGE,		D_OBJC },
  { "synthesize",	RID_AT_SYNTHESIZE,	D_OBJC },
  { "dynamic",		RID_AT_DYNAMIC,		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 },
  /* These are recognized inside a property attribute list */
  { "assign",		RID_ASSIGN,		D_OBJC },
  { "atomic",		RID_PROPATOMIC,		D_OBJC },
  { "copy",		RID_COPY,		D_OBJC },
  { "getter",		RID_GETTER,		D_OBJC },
  { "nonatomic",	RID_NONATOMIC,		D_OBJC },
  { "readonly",		RID_READONLY,		D_OBJC },
  { "readwrite",	RID_READWRITE,		D_OBJC },
  { "retain",		RID_RETAIN,		D_OBJC },
  { "setter",		RID_SETTER,		D_OBJC },
  /* These are Objective C implementation of nullability, accepted only in
     specific contexts.  */
  { "null_unspecified", RID_NULL_UNSPECIFIED,	D_OBJC },
  { "nullable",		RID_NULLABLE,		D_OBJC },
  { "nonnull",		RID_NONNULL,		D_OBJC },
  { "null_resettable",	RID_NULL_RESETTABLE,	D_OBJC },
};

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

/* Return identifier for address space AS.  */

const char *
c_addr_space_name (addr_space_t as)
{
  int rid = RID_FIRST_ADDR_SPACE + as;
  gcc_assert (ridpointers [rid]);
  return IDENTIFIER_POINTER (ridpointers [rid]);
}

/* 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 (integer_type_node, 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) (loc, 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, charsz;
  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))
    {
      charsz = 1;
      e_type = char_type_node;
    }
  else if (flag_char8_t && TREE_TYPE (value) == char8_array_type_node)
    {
      charsz = TYPE_PRECISION (char8_type_node) / BITS_PER_UNIT;
      e_type = char8_type_node;
    }
  else if (TREE_TYPE (value) == char16_array_type_node)
    {
      charsz = TYPE_PRECISION (char16_type_node) / BITS_PER_UNIT;
      e_type = char16_type_node;
    }
  else if (TREE_TYPE (value) == char32_array_type_node)
    {
      charsz = TYPE_PRECISION (char32_type_node) / BITS_PER_UNIT;
      e_type = char32_type_node;
    }
  else
    {
      charsz = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
      e_type = wchar_type_node;
    }

  /* This matters only for targets where ssizetype has smaller precision
     than 32 bits.  */
  if (wi::lts_p (wi::to_wide (TYPE_MAX_VALUE (ssizetype)), length))
    {
      error ("size of string literal is too large");
      length = tree_to_shwi (TYPE_MAX_VALUE (ssizetype)) / charsz * charsz;
      char *str = CONST_CAST (char *, TREE_STRING_POINTER (value));
      memset (str + length, '\0',
	      MIN (TREE_STRING_LENGTH (value) - length, charsz));
      TREE_STRING_LENGTH (value) = length;
    }
  nchars = length / charsz;

  /* 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 (size_int (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;
}

/* Given a string of type STRING_TYPE, determine what kind of string
   token would give an equivalent execution encoding: CPP_STRING,
   CPP_STRING16, or CPP_STRING32.  Return CPP_OTHER in case of error.
   This may not be exactly the string token type that initially created
   the string, since CPP_WSTRING is indistinguishable from the 16/32 bit
   string type, and CPP_UTF8STRING is indistinguishable from CPP_STRING
   at this point.

   This effectively reverses part of the logic in lex_string and
   fix_string_type.  */

static enum cpp_ttype
get_cpp_ttype_from_string_type (tree string_type)
{
  gcc_assert (string_type);
  if (TREE_CODE (string_type) == POINTER_TYPE)
    string_type = TREE_TYPE (string_type);

  if (TREE_CODE (string_type) != ARRAY_TYPE)
    return CPP_OTHER;

  tree element_type = TREE_TYPE (string_type);
  if (TREE_CODE (element_type) != INTEGER_TYPE)
    return CPP_OTHER;

  int bits_per_character = TYPE_PRECISION (element_type);
  switch (bits_per_character)
    {
    case 8:
      return CPP_STRING;  /* It could have also been CPP_UTF8STRING.  */
    case 16:
      return CPP_STRING16;
    case 32:
      return CPP_STRING32;
    }

  return CPP_OTHER;
}

/* The global record of string concatentations, for use in
   extracting locations within string literals.  */

GTY(()) string_concat_db *g_string_concat_db;

/* Implementation of LANG_HOOKS_GET_SUBSTRING_LOCATION.  */

const char *
c_get_substring_location (const substring_loc &substr_loc,
			  location_t *out_loc)
{
  enum cpp_ttype tok_type
    = get_cpp_ttype_from_string_type (substr_loc.get_string_type ());
  if (tok_type == CPP_OTHER)
    return "unrecognized string type";

  return get_location_within_string (parse_in, g_string_concat_db,
				     substr_loc.get_fmt_string_loc (),
				     tok_type,
				     substr_loc.get_caret_idx (),
				     substr_loc.get_start_idx (),
				     substr_loc.get_end_idx (),
				     out_loc);
}


/* Return true iff T is a boolean promoted to int.  */

bool
bool_promoted_to_int_p (tree t)
{
  return (CONVERT_EXPR_P (t)
	  && TREE_TYPE (t) == integer_type_node
	  && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == BOOLEAN_TYPE);
}

/* vector_targets_convertible_p is used for vector pointer types.  The
   callers perform various checks that the qualifiers are satisfactory,
   while OTOH vector_targets_convertible_p ignores the number of elements
   in the vectors.  That's fine with vector pointers as we can consider,
   say, a vector of 8 elements as two consecutive vectors of 4 elements,
   and that does not require and conversion of the pointer values.
   In contrast, vector_types_convertible_p and
   vector_types_compatible_elements_p are used for vector value types.  */
/* 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 (VECTOR_TYPE_P (t1) && VECTOR_TYPE_P (t2)
      && (TYPE_VECTOR_OPAQUE (t1) || TYPE_VECTOR_OPAQUE (t2))
      && tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2)))
    return true;

  return false;
}

/* vector_types_convertible_p is used for vector value types.
   It could in principle call vector_targets_convertible_p as a subroutine,
   but then the check for vector type would be duplicated with its callers,
   and also the purpose of vector_targets_convertible_p would become
   muddled.
   Where vector_types_convertible_p returns true, a conversion might still be
   needed to make the types match.
   In contrast, vector_targets_convertible_p is used for vector pointer
   values, and vector_types_compatible_elements_p is used specifically
   in the context for binary operators, as a check if use is possible without
   conversion.  */
/* 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 ((TYPE_VECTOR_OPAQUE (t1) || TYPE_VECTOR_OPAQUE (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
	 || known_eq (TYPE_VECTOR_SUBPARTS (t1),
		      TYPE_VECTOR_SUBPARTS (t2)))
     && (INTEGRAL_TYPE_P (TREE_TYPE (t1))
	 == INTEGRAL_TYPE_P (TREE_TYPE (t2))));

  if (!convertible_lax || flag_lax_vector_conversions)
    return convertible_lax;

  if (known_eq (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;
}

/* Build a VEC_PERM_EXPR if V0, V1 and MASK are not error_mark_nodes
   and have vector types, V0 has the same type as V1, and the number of
   elements of V0, V1, MASK is the same.

   In case V1 is a NULL_TREE it is assumed that __builtin_shuffle was
   called with two arguments.  In this case implementation passes the
   first argument twice in order to share the same tree code.  This fact
   could enable the mask-values being twice the vector length.  This is
   an implementation accident and this semantics is not guaranteed to
   the user.  */
tree
c_build_vec_perm_expr (location_t loc, tree v0, tree v1, tree mask,
		       bool complain)
{
  tree ret;
  bool wrap = true;
  bool maybe_const = false;
  bool two_arguments = false;

  if (v1 == NULL_TREE)
    {
      two_arguments = true;
      v1 = v0;
    }

  if (v0 == error_mark_node || v1 == error_mark_node
      || mask == error_mark_node)
    return error_mark_node;

  if (!gnu_vector_type_p (TREE_TYPE (mask))
      || !VECTOR_INTEGER_TYPE_P (TREE_TYPE (mask)))
    {
      if (complain)
	error_at (loc, "%<__builtin_shuffle%> last argument must "
		       "be an integer vector");
      return error_mark_node;
    }

  if (!gnu_vector_type_p (TREE_TYPE (v0))
      || !gnu_vector_type_p (TREE_TYPE (v1)))
    {
      if (complain)
	error_at (loc, "%<__builtin_shuffle%> arguments must be vectors");
      return error_mark_node;
    }

  if (TYPE_MAIN_VARIANT (TREE_TYPE (v0)) != TYPE_MAIN_VARIANT (TREE_TYPE (v1)))
    {
      if (complain)
	error_at (loc, "%<__builtin_shuffle%> argument vectors must be of "
		       "the same type");
      return error_mark_node;
    }

  if (maybe_ne (TYPE_VECTOR_SUBPARTS (TREE_TYPE (v0)),
		TYPE_VECTOR_SUBPARTS (TREE_TYPE (mask)))
      && maybe_ne (TYPE_VECTOR_SUBPARTS (TREE_TYPE (v1)),
		   TYPE_VECTOR_SUBPARTS (TREE_TYPE (mask))))
    {
      if (complain)
	error_at (loc, "%<__builtin_shuffle%> number of elements of the "
		       "argument vector(s) and the mask vector should "
		       "be the same");
      return error_mark_node;
    }

  if (GET_MODE_BITSIZE (SCALAR_TYPE_MODE (TREE_TYPE (TREE_TYPE (v0))))
      != GET_MODE_BITSIZE (SCALAR_TYPE_MODE (TREE_TYPE (TREE_TYPE (mask)))))
    {
      if (complain)
	error_at (loc, "%<__builtin_shuffle%> argument vector(s) inner type "
		       "must have the same size as inner type of the mask");
      return error_mark_node;
    }

  if (!c_dialect_cxx ())
    {
      /* Avoid C_MAYBE_CONST_EXPRs inside VEC_PERM_EXPR.  */
      v0 = c_fully_fold (v0, false, &maybe_const);
      wrap &= maybe_const;

      if (two_arguments)
        v1 = v0 = save_expr (v0);
      else
        {
          v1 = c_fully_fold (v1, false, &maybe_const);
          wrap &= maybe_const;
        }

      mask = c_fully_fold (mask, false, &maybe_const);
      wrap &= maybe_const;
    }
  else if (two_arguments)
    v1 = v0 = save_expr (v0);

  ret = build3_loc (loc, VEC_PERM_EXPR, TREE_TYPE (v0), v0, v1, mask);

  if (!c_dialect_cxx () && !wrap)
    ret = c_wrap_maybe_const (ret, true);

  return ret;
}

/* Build a VEC_PERM_EXPR if V0, V1 are not error_mark_nodes
   and have vector types, V0 has the same element type as V1, and the
   number of elements the result is that of MASK.  */
tree
c_build_shufflevector (location_t loc, tree v0, tree v1,
		       const vec<tree> &mask, bool complain)
{
  tree ret;
  bool wrap = true;
  bool maybe_const = false;

  if (v0 == error_mark_node || v1 == error_mark_node)
    return error_mark_node;

  if (!gnu_vector_type_p (TREE_TYPE (v0))
      || !gnu_vector_type_p (TREE_TYPE (v1)))
    {
      if (complain)
	error_at (loc, "%<__builtin_shufflevector%> arguments must be vectors");
      return error_mark_node;
    }

  /* ???  In principle one could select a constant part of a variable size
     vector but things get a bit awkward with trying to support this here.  */
  unsigned HOST_WIDE_INT v0n, v1n;
  if (!TYPE_VECTOR_SUBPARTS (TREE_TYPE (v0)).is_constant (&v0n)
      || !TYPE_VECTOR_SUBPARTS (TREE_TYPE (v1)).is_constant (&v1n))
    {
      if (complain)
	error_at (loc, "%<__builtin_shufflevector%> arguments must be constant"
		  " size vectors");
      return error_mark_node;
    }

  if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (v0)))
      != TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (v1))))
    {
      if (complain)
	error_at (loc, "%<__builtin_shufflevector%> argument vectors must "
		  "have the same element type");
      return error_mark_node;
    }

  if (!pow2p_hwi (mask.length ()))
    {
      if (complain)
	error_at (loc, "%<__builtin_shufflevector%> must specify a result "
		  "with a power of two number of elements");
      return error_mark_node;
    }

  if (!c_dialect_cxx ())
    {
      /* Avoid C_MAYBE_CONST_EXPRs inside VEC_PERM_EXPR.  */
      v0 = c_fully_fold (v0, false, &maybe_const);
      wrap &= maybe_const;

      v1 = c_fully_fold (v1, false, &maybe_const);
      wrap &= maybe_const;
    }

  unsigned HOST_WIDE_INT maskl = MAX (mask.length (), MAX (v0n, v1n));
  unsigned HOST_WIDE_INT pad = (v0n < maskl ? maskl - v0n : 0);
  vec_perm_builder sel (maskl, maskl, 1);
  unsigned i;
  for (i = 0; i < mask.length (); ++i)
    {
      tree idx = mask[i];
      if (!tree_fits_shwi_p (idx))
	{
	  if (complain)
	    error_at (loc, "invalid element index %qE to "
		      "%<__builtin_shufflevector%>", idx);
	  return error_mark_node;
	}
      HOST_WIDE_INT iidx = tree_to_shwi (idx);
      if (iidx < -1
	  || (iidx != -1
	      && (unsigned HOST_WIDE_INT) iidx >= v0n + v1n))
	{
	  if (complain)
	    error_at (loc, "invalid element index %qE to "
		      "%<__builtin_shufflevector%>", idx);
	  return error_mark_node;
	}
      /* ???  Our VEC_PERM_EXPR does not allow for -1 yet.  */
      if (iidx == -1)
	iidx = i;
      /* ???  Our VEC_PERM_EXPR does not allow different sized inputs,
	 so pad out a smaller v0.  */
      else if ((unsigned HOST_WIDE_INT) iidx >= v0n)
	iidx += pad;
      sel.quick_push (iidx);
    }
  /* ???  VEC_PERM_EXPR does not support a result that is smaller than
     the inputs, so we have to pad id out.  */
  for (; i < maskl; ++i)
    sel.quick_push (i);

  vec_perm_indices indices (sel, 2, maskl);

  tree ret_type = build_vector_type (TREE_TYPE (TREE_TYPE (v0)), maskl);
  tree mask_type = build_vector_type (build_nonstandard_integer_type
		(TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (ret_type))), 1),
		maskl);
  /* Pad out arguments to the common vector size.  */
  if (v0n < maskl)
    {
      constructor_elt elt = { NULL_TREE, build_zero_cst (TREE_TYPE (v0)) };
      v0 = build_constructor_single (ret_type, NULL_TREE, v0);
      for (i = 1; i < maskl / v0n; ++i)
	vec_safe_push (CONSTRUCTOR_ELTS (v0), elt);
    }
  if (v1n < maskl)
    {
      constructor_elt elt = { NULL_TREE, build_zero_cst (TREE_TYPE (v1)) };
      v1 = build_constructor_single (ret_type, NULL_TREE, v1);
      for (i = 1; i < maskl / v1n; ++i)
	vec_safe_push (CONSTRUCTOR_ELTS (v1), elt);
    }
  ret = build3_loc (loc, VEC_PERM_EXPR, ret_type, v0, v1,
		    vec_perm_indices_to_tree (mask_type, indices));
  /* Get the lowpart we are interested in.  */
  if (mask.length () < maskl)
    {
      tree lpartt = build_vector_type (TREE_TYPE (ret_type), mask.length ());
      ret = build3_loc (loc, BIT_FIELD_REF,
			lpartt, ret, TYPE_SIZE (lpartt), bitsize_zero_node);
      /* Wrap the lowpart operation in a TARGET_EXPR so it gets a separate
	 temporary during gimplification.  See PR101530 for cases where
	 we'd otherwise end up with non-toplevel BIT_FIELD_REFs.  */
      tree tem = create_tmp_var_raw (lpartt);
      DECL_CONTEXT (tem) = current_function_decl;
      ret = build4 (TARGET_EXPR, lpartt, tem, ret, NULL_TREE, NULL_TREE);
      TREE_SIDE_EFFECTS (ret) = 1;
    }

  if (!c_dialect_cxx () && !wrap)
    ret = c_wrap_maybe_const (ret, true);

  return ret;
}

/* Build a VEC_CONVERT ifn for __builtin_convertvector builtin.  */

tree
c_build_vec_convert (location_t loc1, tree expr, location_t loc2, tree type,
		     bool complain)
{
  if (error_operand_p (type))
    return error_mark_node;
  if (error_operand_p (expr))
    return error_mark_node;

  if (!gnu_vector_type_p (TREE_TYPE (expr))
      || (!VECTOR_INTEGER_TYPE_P (TREE_TYPE (expr))
	  && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (expr))))
    {
      if (complain)
	error_at (loc1, "%<__builtin_convertvector%> first argument must "
			"be an integer or floating vector");
      return error_mark_node;
    }

  if (!gnu_vector_type_p (type)
      || (!VECTOR_INTEGER_TYPE_P (type) && !VECTOR_FLOAT_TYPE_P (type)))
    {
      if (complain)
	error_at (loc2, "%<__builtin_convertvector%> second argument must "
			"be an integer or floating vector type");
      return error_mark_node;
    }

  if (maybe_ne (TYPE_VECTOR_SUBPARTS (TREE_TYPE (expr)),
		TYPE_VECTOR_SUBPARTS (type)))
    {
      if (complain)
	error_at (loc1, "%<__builtin_convertvector%> number of elements "
			"of the first argument vector and the second argument "
			"vector type should be the same");
      return error_mark_node;
    }

  if ((TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (expr)))
       == TYPE_MAIN_VARIANT (TREE_TYPE (type)))
      || (VECTOR_INTEGER_TYPE_P (TREE_TYPE (expr))
	  && VECTOR_INTEGER_TYPE_P (type)
	  && (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (expr)))
	      == TYPE_PRECISION (TREE_TYPE (type)))))
    return build1_loc (loc1, VIEW_CONVERT_EXPR, type, expr);

  bool wrap = true;
  bool maybe_const = false;
  tree ret;
  if (!c_dialect_cxx ())
    {
      /* Avoid C_MAYBE_CONST_EXPRs inside of VEC_CONVERT argument.  */
      expr = c_fully_fold (expr, false, &maybe_const);
      wrap &= maybe_const;
    }

  ret = build_call_expr_internal_loc (loc1, IFN_VEC_CONVERT, type, 1, expr);

  if (!wrap)
    ret = c_wrap_maybe_const (ret, true);

  return ret;
}

/* Like tree.cc:get_narrower, but retain conversion from C++0x scoped enum
   to integral type.  */

tree
c_common_get_narrower (tree op, int *unsignedp_ptr)
{
  op = get_narrower (op, unsignedp_ptr);

  if (TREE_CODE (TREE_TYPE (op)) == ENUMERAL_TYPE
      && ENUM_IS_SCOPED (TREE_TYPE (op)))
    {
      /* C++0x scoped enumerations don't implicitly convert to integral
	 type; if we stripped an explicit conversion to a larger type we
	 need to replace it so common_type will still work.  */
      tree type = c_common_type_for_size (TYPE_PRECISION (TREE_TYPE (op)),
					  TYPE_UNSIGNED (TREE_TYPE (op)));
      op = fold_convert (type, op);
    }
  return op;
}

/* 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 = c_common_get_narrower (op0, &unsigned0);
  arg1 = c_common_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;
}

/* Returns true iff any integer value of type FROM_TYPE can be represented as
   real of type TO_TYPE.  This is a helper function for unsafe_conversion_p.  */

static bool
int_safely_convertible_to_real_p (const_tree from_type, const_tree to_type)
{
  tree type_low_bound = TYPE_MIN_VALUE (from_type);
  tree type_high_bound = TYPE_MAX_VALUE (from_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);

  return exact_real_truncate (TYPE_MODE (to_type), &real_low_bound)
	 && exact_real_truncate (TYPE_MODE (to_type), &real_high_bound);
}

/* Checks if expression EXPR of complex/real/integer type cannot be converted
   to the complex/real/integer type TYPE.  Function returns non-zero when:
	* EXPR is a constant which cannot be exactly converted to TYPE.
	* EXPR is not a constant and size of EXPR's type > than size of TYPE,
	  for EXPR type and TYPE being both integers or both real, or both
	  complex.
	* EXPR is not a constant of complex type and TYPE is a real or
	  an integer.
	* EXPR is not a constant of real type and TYPE is an integer.
	* EXPR is not a constant of integer type which cannot be
	  exactly converted to real type.

   Function allows conversions between types of different signedness if
   CHECK_SIGN is false and can return SAFE_CONVERSION (zero) in that
   case.  Function can return UNSAFE_SIGN if CHECK_SIGN is true.

   RESULT, when non-null is the result of the conversion.  When constant
   it is included in the text of diagnostics.

   Function allows conversions from complex constants to non-complex types,
   provided that imaginary part is zero and real part can be safely converted
   to TYPE.  */

enum conversion_safety
unsafe_conversion_p (tree type, tree expr, tree result, bool check_sign)
{
  enum conversion_safety give_warning = SAFE_CONVERSION; /* is 0 or false */
  tree expr_type = TREE_TYPE (expr);

  expr = fold_for_warn (expr);

  if (TREE_CODE (expr) == REAL_CST || TREE_CODE (expr) == INTEGER_CST)
    {
      /* If type is complex, we are interested in compatibility with
	 underlying type.  */
      if (TREE_CODE (type) == COMPLEX_TYPE)
	  type = TREE_TYPE (type);

      /* 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 = UNSAFE_REAL;
	}
      /* 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)
	    {
	      if (check_sign)
		give_warning = UNSAFE_SIGN;
	    }
	  else if (!TYPE_UNSIGNED (type) && TYPE_UNSIGNED (expr_type))
	    {
	      if (check_sign)
		give_warning = UNSAFE_SIGN;
	    }
	  else
	    give_warning = UNSAFE_OTHER;
	}
      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 = UNSAFE_REAL;
	    }
	  /* 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 = UNSAFE_REAL;
	    }
	}
    }

  else if (TREE_CODE (expr) == COMPLEX_CST)
    {
      tree imag_part = TREE_IMAGPART (expr);
      /* Conversion from complex constant with zero imaginary part,
	 perform check for conversion of real part.  */
      if ((TREE_CODE (imag_part) == REAL_CST
	   && real_zerop (imag_part))
	  || (TREE_CODE (imag_part) == INTEGER_CST
	      && integer_zerop (imag_part)))
	/* Note: in this branch we use recursive call to unsafe_conversion_p
	   with different type of EXPR, but it is still safe, because when EXPR
	   is a constant, it's type is not used in text of generated warnings
	   (otherwise they could sound misleading).  */
	return unsafe_conversion_p (type, TREE_REALPART (expr), result,
				    check_sign);
      /* Conversion from complex constant with non-zero imaginary part.  */
      else
	{
	  /* Conversion to complex type.
	     Perform checks for both real and imaginary parts.  */
	  if (TREE_CODE (type) == COMPLEX_TYPE)
	    {
	      enum conversion_safety re_safety =
		unsafe_conversion_p (type, TREE_REALPART (expr),
				     result, check_sign);
	      enum conversion_safety im_safety =
		unsafe_conversion_p (type, imag_part, result, check_sign);

	      /* Merge the results into appropriate single warning.  */

	      /* Note: this case includes SAFE_CONVERSION, i.e. success.  */
	      if (re_safety == im_safety)
		give_warning = re_safety;
	      else if (!re_safety && im_safety)
		give_warning = im_safety;
	      else if (re_safety && !im_safety)
		give_warning = re_safety;
	      else
		give_warning = UNSAFE_OTHER;
	    }
	  /* Warn about conversion from complex to real or integer type.  */
	  else
	    give_warning = UNSAFE_IMAGINARY;
	}
    }

  /* Checks for remaining case: EXPR is not constant.  */
  else
    {
      /* Warn for real types converted to integer types.  */
      if (TREE_CODE (expr_type) == REAL_TYPE
	  && TREE_CODE (type) == INTEGER_TYPE)
	give_warning = UNSAFE_REAL;

      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 SAFE_CONVERSION;
		  /* 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 SAFE_CONVERSION;
		}
	    }
	  /* Warn for integer types converted to smaller integer types.  */
	  if (TYPE_PRECISION (type) < TYPE_PRECISION (expr_type))
	    give_warning = UNSAFE_OTHER;

	  /* 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)))
		   && check_sign)
	    give_warning = UNSAFE_SIGN;
	}

      /* 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)
	{
	  /* Don't warn about char y = 0xff; float x = (int) y;  */
	  expr = get_unwidened (expr, 0);
	  expr_type = TREE_TYPE (expr);

	  if (!int_safely_convertible_to_real_p (expr_type, type))
	    give_warning = UNSAFE_OTHER;
	}

      /* 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 = UNSAFE_REAL;

      /* Check conversion between two complex types.  */
      else if (TREE_CODE (expr_type) == COMPLEX_TYPE
	       && TREE_CODE (type) == COMPLEX_TYPE)
	{
	  /* Extract underlying types (i.e., type of real and imaginary
	     parts) of expr_type and type.  */
	  tree from_type = TREE_TYPE (expr_type);
	  tree to_type = TREE_TYPE (type);

	  /* Warn for real types converted to integer types.  */
	  if (TREE_CODE (from_type) == REAL_TYPE
	      && TREE_CODE (to_type) == INTEGER_TYPE)
	    give_warning = UNSAFE_REAL;

	  /* Warn for real types converted to smaller real types.  */
	  else if (TREE_CODE (from_type) == REAL_TYPE
		   && TREE_CODE (to_type) == REAL_TYPE
		   && TYPE_PRECISION (to_type) < TYPE_PRECISION (from_type))
	    give_warning = UNSAFE_REAL;

	  /* Check conversion for complex integer types.  Here implementation
	     is simpler than for real-domain integers because it does not
	     involve sophisticated cases, such as bitmasks, casts, etc.  */
	  else if (TREE_CODE (from_type) == INTEGER_TYPE
		   && TREE_CODE (to_type) == INTEGER_TYPE)
	    {
	      /* Warn for integer types converted to smaller integer types.  */
	      if (TYPE_PRECISION (to_type) < TYPE_PRECISION (from_type))
		give_warning = UNSAFE_OTHER;

	      /* Check for different signedness, see case for real-domain
		 integers (above) for a more detailed comment.  */
	      else if (((TYPE_PRECISION (to_type) == TYPE_PRECISION (from_type)
			 && TYPE_UNSIGNED (to_type) != TYPE_UNSIGNED (from_type))
			|| (TYPE_UNSIGNED (to_type) && !TYPE_UNSIGNED (from_type)))
		       && check_sign)
		give_warning = UNSAFE_SIGN;
	    }
	  else if (TREE_CODE (from_type) == INTEGER_TYPE
		   && TREE_CODE (to_type) == REAL_TYPE
		   && !int_safely_convertible_to_real_p (from_type, to_type))
	    give_warning = UNSAFE_OTHER;
	}

      /* Warn for complex types converted to real or integer types.  */
      else if (TREE_CODE (expr_type) == COMPLEX_TYPE
	       && TREE_CODE (type) != COMPLEX_TYPE)
	give_warning = UNSAFE_IMAGINARY;
    }

  return give_warning;
}


/* 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.
   INIT_CONST is true if the conversion is for arithmetic types for a static
   initializer and folding must apply accordingly (discarding floating-point
   exceptions and assuming the default rounding mode is in effect).  */

tree
convert_and_check (location_t loc, tree type, tree expr, bool init_const)
{
  tree result;
  tree expr_for_warning;

  /* Convert from a value with possible excess precision rather than
     via the semantic type, but do not warn about values not fitting
     exactly in the semantic type.  */
  if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
    {
      tree orig_type = TREE_TYPE (expr);
      expr = TREE_OPERAND (expr, 0);
      expr_for_warning = (init_const
			  ? convert_init (orig_type, expr)
			  : convert (orig_type, expr));
      if (orig_type == type)
	return expr_for_warning;
    }
  else
    expr_for_warning = expr;

  if (TREE_TYPE (expr) == type)
    return expr;

  result = init_const ? convert_init (type, expr) : convert (type, expr);

  if (c_inhibit_evaluation_warnings == 0
      && !TREE_OVERFLOW_P (expr)
      && result != error_mark_node)
    warnings_for_convert_and_check (loc, type, expr_for_warning, 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 bool warning_candidate_p (tree);
static bool candidate_equal_p (const_tree, const_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 || !candidate_equal_p (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 (candidate_equal_p (tmp2->expr, add->expr))
	  {
	    found = 1;
	    if (!tmp2->writer)
	      tmp2->writer = add->writer;
	  }
      if (!found)
	{
	  *end = copy ? new_tlist (NULL, add->expr, add->writer) : add;
	  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 (candidate_equal_p (tmp->expr, written))
      return;

  while (list)
    {
      if (candidate_equal_p (list->expr, written)
	  && !candidate_equal_p (list->writer, writer)
	  && (!only_writes || list->writer))
	{
	  warned_ids = new_tlist (warned_ids, written, NULL_TREE);
	  warning_at (EXPR_LOC_OR_LOC (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 bool
warning_candidate_p (tree x)
{
  if (DECL_P (x) && DECL_ARTIFICIAL (x))
    return false;

  if (TREE_CODE (x) == BLOCK)
    return false;

  /* VOID_TYPE_P (TREE_TYPE (x)) is workaround for cp/tree.cc
     (lvalue_p) crash on TRY/CATCH. */
  if (TREE_TYPE (x) == NULL_TREE || VOID_TYPE_P (TREE_TYPE (x)))
    return false;

  if (!lvalue_p (x))
    return false;

  /* No point to track non-const calls, they will never satisfy
     operand_equal_p.  */
  if (TREE_CODE (x) == CALL_EXPR && (call_expr_flags (x) & ECF_CONST) == 0)
    return false;

  if (TREE_CODE (x) == STRING_CST)
    return false;

  return true;
}

/* Return nonzero if X and Y appear to be the same candidate (or NULL) */
static bool
candidate_equal_p (const_tree x, const_tree y)
{
  return (x == y) || (x && y && operand_equal_p (x, y, 0));
}

/* 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;

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

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

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

  switch (code)
    {
    case CONSTRUCTOR:
    case SIZEOF_EXPR:
    case PAREN_SIZEOF_EXPR:
      return;

    case COMPOUND_EXPR:
    case TRUTH_ANDIF_EXPR:
    case TRUTH_ORIF_EXPR:
    sequenced_binary:
      tmp_before = tmp_nosp = tmp_list2 = 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, &tmp_list2, NULL_TREE);
      warn_for_collisions (tmp_list2);
      merge_tlist (pbefore_sp, tmp_list3, 0);
      merge_tlist (pno_sp, tmp_list2, 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, 0);

      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 (candidate_equal_p (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;
	    merge_tlist (&tmp_list3, tmp_nosp, 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;

    case VIEW_CONVERT_EXPR:
      if (location_wrapper_p (x))
	{
	  x = TREE_OPERAND (x, 0);
	  goto restart;
	}
      goto do_default;

    case LSHIFT_EXPR:
    case RSHIFT_EXPR:
    case COMPONENT_REF:
    case ARRAY_REF:
      if (cxx_dialect >= cxx17)
	goto sequenced_binary;
      goto do_default;

    default:
    do_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;
    }
}

static constexpr size_t verify_sequence_points_limit = 1024;

/* Called from verify_sequence_points via walk_tree.  */

static tree
verify_tree_lim_r (tree *tp, int *walk_subtrees, void *data)
{
  if (++*((size_t *) data) > verify_sequence_points_limit)
    return integer_zero_node;

  if (TYPE_P (*tp))
    *walk_subtrees = 0;

  return NULL_TREE;
}

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

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

  /* verify_tree is highly recursive, and merge_tlist is O(n^2),
     so we return early if the expression is too big.  */
  size_t n = 0;
  if (walk_tree (&expr, verify_tree_lim_r, &n, nullptr))
    return;

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

  verify_tree (expr, &before_sp, &after_sp, NULL_TREE);
  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 (location_t loc, tree value)
{
  if (value == NULL_TREE)
    return 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_at (loc, "case label does not reduce to an integer constant");
      value = error_mark_node;
    }

  constant_expression_warning (value);

  return value;
}

/* 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)
{
  int i;

  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);

  for (i = 0; i < NUM_INT_N_ENTS; i ++)
    if (int_n_enabled_p[i]
	&& bits == int_n_data[i].bitsize)
      return (unsignedp ? int_n_trees[i].unsigned_type
	      : int_n_trees[i].signed_type);

  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 NULL_TREE;
}

/* 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 mode_class mclass;
  if (ibit == 0)
    mclass = unsignedp ? MODE_UFRACT : MODE_FRACT;
  else
    mclass = unsignedp ? MODE_UACCUM : MODE_ACCUM;

  opt_scalar_mode opt_mode;
  scalar_mode mode;
  FOR_EACH_MODE_IN_CLASS (opt_mode, mclass)
    {
      mode = opt_mode.require ();
      if (GET_MODE_IBIT (mode) >= ibit && GET_MODE_FBIT (mode) >= fbit)
	break;
    }

  if (!opt_mode.exists (&mode) || !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 NULL_TREE;
    }

  return c_common_type_for_mode (mode, satp);
}

/* Used for communication between c_common_type_for_mode and
   c_register_builtin_type.  */
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 (machine_mode mode, int unsignedp)
{
  tree t;
  int i;

  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;

  for (i = 0; i < NUM_INT_N_ENTS; i ++)
    if (int_n_enabled_p[i]
	&& mode == int_n_data[i].m)
      return (unsignedp ? int_n_trees[i].unsigned_type
	      : int_n_trees[i].signed_type);

  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;

  for (i = 0; i < NUM_FLOATN_NX_TYPES; i++)
    if (FLOATN_NX_TYPE_NODE (i) != NULL_TREE
	&& mode == TYPE_MODE (FLOATN_NX_TYPE_NODE (i)))
      return FLOATN_NX_TYPE_NODE (i);

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

  if (mode == TYPE_MODE (build_pointer_type (char_type_node))
      || mode == TYPE_MODE (build_pointer_type (integer_type_node)))
    {
      unsigned int precision
	= GET_MODE_PRECISION (as_a <scalar_int_mode> (mode));
      return (unsignedp
	      ? make_unsigned_type (precision)
	      : make_signed_type (precision));
    }

  if (COMPLEX_MODE_P (mode))
    {
      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;

      for (i = 0; i < NUM_FLOATN_NX_TYPES; i++)
	if (COMPLEX_FLOATN_NX_TYPE_NODE (i) != NULL_TREE
	    && mode == TYPE_MODE (COMPLEX_FLOATN_NX_TYPE_NODE (i)))
	  return COMPLEX_FLOATN_NX_TYPE_NODE (i);

      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 (GET_MODE_CLASS (mode) == MODE_VECTOR_BOOL
	   && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
    {
      unsigned int elem_bits = vector_element_size (GET_MODE_BITSIZE (mode),
						    GET_MODE_NUNITS (mode));
      tree bool_type = build_nonstandard_boolean_type (elem_bits);
      return build_vector_type_for_mode (bool_type, mode);
    }
  else if (VECTOR_MODE_P (mode)
	   && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
    {
      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 (dfloat32_type_node != NULL_TREE
      && mode == TYPE_MODE (dfloat32_type_node))
    return dfloat32_type_node;
  if (dfloat64_type_node != NULL_TREE
      && mode == TYPE_MODE (dfloat64_type_node))
    return dfloat64_type_node;
  if (dfloat128_type_node != NULL_TREE
      && 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))
    {
      tree type = TREE_VALUE (t);
      if (TYPE_MODE (type) == mode
	  && VECTOR_TYPE_P (type) == VECTOR_MODE_P (mode)
	  && !!unsignedp == !!TYPE_UNSIGNED (type))
	return type;
    }
  return NULL_TREE;
}

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;
  int i;

  /* 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;

  for (i = 0; i < NUM_INT_N_ENTS; i ++)
    if (int_n_enabled_p[i]
	&& (type1 == int_n_trees[i].unsigned_type
	    || type1 == int_n_trees[i].signed_type))
      return (unsignedp ? int_n_trees[i].unsigned_type
	      : int_n_trees[i].signed_type);

#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);

  for (i = 0; i < NUM_INT_N_ENTS; i ++)
    if (int_n_enabled_p[i]
	&& TYPE_MODE (type) == int_n_data[i].m
	&& TYPE_PRECISION (type) == int_n_data[i].bitsize)
      return (unsignedp ? int_n_trees[i].unsigned_type
	      : int_n_trees[i].signed_type);

#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)
{
  int i;

  /* 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);
  for (i = 0; i < NUM_INT_N_ENTS; i ++)
    if (int_n_enabled_p[i]
	&& width == int_n_data[i].bitsize)
      return (unsignedp ? int_n_trees[i].unsigned_type
	      : int_n_trees[i].signed_type);
  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 (UNKNOWN_LOCATION,
		     TYPE_DECL, get_identifier (name), type);
  DECL_ARTIFICIAL (decl) = 1;
  if (!TYPE_NAME (type))
    TYPE_NAME (type) = decl;
  lang_hooks.decls.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.
   RICHLOC is a rich location for the message, containing either
   three separate locations for each of the operator and operands

      lhs op rhs
      ~~~ ^~ ~~~

   (C FE), or one location ranging over all over them

      lhs op rhs
      ~~~~^~~~~~

   (C++ FE).  */

void
binary_op_error (rich_location *richloc, 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 (richloc,
	    "invalid operands to binary %s (have %qT and %qT)",
	    opname, type0, type1);
}

/* Given an expression as a tree, return its original type.  Do this
   by stripping any conversion that preserves the sign and precision.  */
static tree
expr_original_type (tree expr)
{
  STRIP_SIGN_NOPS (expr);
  return TREE_TYPE (expr);
}

/* 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.

   LOC is the location of the comparison.

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

tree
shorten_compare (location_t loc, 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 = c_common_get_narrower (op0, &unsignedp0);
  primop1 = c_common_get_narrower (op1, &unsignedp1);

  /* If primopN is first sign-extended from primopN's precision to opN's
     precision, then zero-extended from opN's precision to
     *restype_ptr precision, shortenings might be invalid.  */
  if (TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (TREE_TYPE (op0))
      && TYPE_PRECISION (TREE_TYPE (op0)) < TYPE_PRECISION (*restype_ptr)
      && !unsignedp0
      && TYPE_UNSIGNED (TREE_TYPE (op0)))
    primop0 = op0;
  if (TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (TREE_TYPE (op1))
      && TYPE_PRECISION (TREE_TYPE (op1)) < TYPE_PRECISION (*restype_ptr)
      && !unsignedp1
      && TYPE_UNSIGNED (TREE_TYPE (op1)))
    primop1 = op1;

  /* 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))
    {
      std::swap (primop0, primop1);
      std::swap (op0, op1);
      *op0_ptr = op0;
      *op1_ptr = op1;
      std::swap (unsignedp0, unsignedp1);
      std::swap (real1, real2);

      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);