Middle-end _BitInt support [PR102989]

Middle-end _BitInt support [PR102989]

The following patch introduces the middle-end part of the _BitInt
support, a new BITINT_TYPE, handling it where needed, except the lowering
pass and sanitizer support.

2023-09-06  Jakub Jelinek  <jakub@redhat.com>

	PR c/102989
	* tree.def (BITINT_TYPE): New type.
	* tree.h (TREE_CHECK6, TREE_NOT_CHECK6): Define.
	(NUMERICAL_TYPE_CHECK, INTEGRAL_TYPE_P): Include
	BITINT_TYPE.
	(BITINT_TYPE_P): Define.
	(CONSTRUCTOR_BITFIELD_P): Return true even for BLKmode bit-fields if
	they have BITINT_TYPE type.
	(tree_check6, tree_not_check6): New inline functions.
	(any_integral_type_check): Include BITINT_TYPE.
	(build_bitint_type): Declare.
	* tree.cc (tree_code_size, wide_int_to_tree_1, cache_integer_cst,
	build_zero_cst, type_hash_canon_hash, type_cache_hasher::equal,
	type_hash_canon): Handle BITINT_TYPE.
	(bitint_type_cache): New variable.
	(build_bitint_type): New function.
	(signed_or_unsigned_type_for, verify_type_variant, verify_type):
	Handle BITINT_TYPE.
	(tree_cc_finalize): Free bitint_type_cache.
	* builtins.cc (type_to_class): Handle BITINT_TYPE.
	(fold_builtin_unordered_cmp): Handle BITINT_TYPE like INTEGER_TYPE.
	* cfgexpand.cc (expand_debug_expr): Punt on BLKmode BITINT_TYPE
	INTEGER_CSTs.
	* convert.cc (convert_to_pointer_1, convert_to_real_1,
	convert_to_complex_1): Handle BITINT_TYPE like INTEGER_TYPE.
	(convert_to_integer_1): Likewise.  For BITINT_TYPE don't check
	GET_MODE_PRECISION (TYPE_MODE (type)).
	* doc/generic.texi (BITINT_TYPE): Document.
	* doc/tm.texi.in (TARGET_C_BITINT_TYPE_INFO): New.
	* doc/tm.texi: Regenerated.
	* dwarf2out.cc (base_type_die, is_base_type, modified_type_die,
	gen_type_die_with_usage): Handle BITINT_TYPE.
	(rtl_for_decl_init): Punt on BLKmode BITINT_TYPE INTEGER_CSTs or
	handle those which fit into shwi.
	* expr.cc (expand_expr_real_1): Define EXTEND_BITINT macro, reduce
	to bitfield precision reads from BITINT_TYPE vars, parameters or
	memory locations.  Expand large/huge BITINT_TYPE INTEGER_CSTs into
	memory.
	* fold-const.cc (fold_convert_loc, make_range_step): Handle
	BITINT_TYPE.
	(extract_muldiv_1): For BITINT_TYPE use TYPE_PRECISION rather than
	GET_MODE_SIZE (SCALAR_INT_TYPE_MODE).
	(native_encode_int, native_interpret_int, native_interpret_expr):
	Handle BITINT_TYPE.
	* gimple-expr.cc (useless_type_conversion_p): Make BITINT_TYPE
	to some other integral type or vice versa conversions non-useless.
	* gimple-fold.cc (gimple_fold_builtin_memset): Punt for BITINT_TYPE.
	(clear_padding_unit): Mention in comment that _BitInt types don't need
	to fit either.
	(clear_padding_bitint_needs_padding_p): New function.
	(clear_padding_type_may_have_padding_p): Handle BITINT_TYPE.
	(clear_padding_type): Likewise.
	* internal-fn.cc (expand_mul_overflow): For unsigned non-mode
	precision operands force pos_neg? to 1.
	(expand_MULBITINT, expand_DIVMODBITINT, expand_FLOATTOBITINT,
	expand_BITINTTOFLOAT): New functions.
	* internal-fn.def (MULBITINT, DIVMODBITINT, FLOATTOBITINT,
	BITINTTOFLOAT): New internal functions.
	* internal-fn.h (expand_MULBITINT, expand_DIVMODBITINT,
	expand_FLOATTOBITINT, expand_BITINTTOFLOAT): Declare.
	* match.pd (non-equality compare simplifications from fold_binary):
	Punt if TYPE_MODE (arg1_type) is BLKmode.
	* pretty-print.h (pp_wide_int): Handle printing of large precision
	wide_ints which would buffer overflow digit_buffer.
	* stor-layout.cc (finish_bitfield_representative): For bit-fields
	with BITINT_TYPE, prefer representatives with precisions in
	multiple of limb precision.
	(layout_type): Handle BITINT_TYPE.  Handle COMPLEX_TYPE with BLKmode
	element type and assert it is BITINT_TYPE.
	* target.def (bitint_type_info): New C target hook.
	* target.h (struct bitint_info): New type.
	* targhooks.cc (default_bitint_type_info): New function.
	* targhooks.h (default_bitint_type_info): Declare.
	* tree-pretty-print.cc (dump_generic_node): Handle BITINT_TYPE.
	Handle printing large wide_ints which would buffer overflow
	digit_buffer.
	* tree-ssa-sccvn.cc: Include target.h.
	(eliminate_dom_walker::eliminate_stmt): Punt for large/huge
	BITINT_TYPE.
	* tree-switch-conversion.cc (jump_table_cluster::emit): For more than
	64-bit BITINT_TYPE subtract low bound from expression and cast to
	64-bit integer type both the controlling expression and case labels.
	* typeclass.h (enum type_class): Add bitint_type_class enumerator.
	* varasm.cc (output_constant): Handle BITINT_TYPE INTEGER_CSTs.
	* vr-values.cc (check_for_binary_op_overflow): Use widest2_int rather
	than widest_int.
	(simplify_using_ranges::simplify_internal_call_using_ranges): Use
	unsigned_type_for rather than build_nonstandard_integer_type.