C _BitInt support [PR102989]

This patch adds the C FE support, c-family support, small libcpp change
so that 123wb and 42uwb suffixes are handled plus glimits.h change
to define BITINT_MAXWIDTH macro.

The previous patches really do nothing without this, which enables
all the support.

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

	PR c/102989
gcc/
	* glimits.h (BITINT_MAXWIDTH): Define if __BITINT_MAXWIDTH__ is
	predefined.
gcc/c-family/
	* c-common.cc (c_common_reswords): Add _BitInt as keyword.
	(unsafe_conversion_p): Handle BITINT_TYPE like INTEGER_TYPE.
	(c_common_signed_or_unsigned_type): Handle BITINT_TYPE.
	(c_common_truthvalue_conversion, c_common_get_alias_set,
	check_builtin_function_arguments): Handle BITINT_TYPE like
	INTEGER_TYPE.
	(sync_resolve_size): Add ORIG_FORMAT argument.  If
	FETCH && !ORIG_FORMAT, type is BITINT_TYPE, return -1 if size isn't
	one of 1, 2, 4, 8 or 16 or if it is 16 but TImode is not supported.
	(atomic_bitint_fetch_using_cas_loop): New function.
	(resolve_overloaded_builtin): Adjust sync_resolve_size caller.  If
	-1 is returned, use atomic_bitint_fetch_using_cas_loop to lower it.
	Formatting fix.
	(keyword_begins_type_specifier): Handle RID_BITINT.
	* c-common.h (enum rid): Add RID_BITINT enumerator.
	* c-cppbuiltin.cc (c_cpp_builtins): For C call
	targetm.c.bitint_type_info and predefine __BITINT_MAXWIDTH__
	and for -fbuilding-libgcc also __LIBGCC_BITINT_LIMB_WIDTH__ and
	__LIBGCC_BITINT_ORDER__ macros if _BitInt is supported.
	* c-lex.cc (interpret_integer): Handle CPP_N_BITINT.
	* c-pretty-print.cc (c_pretty_printer::simple_type_specifier,
	c_pretty_printer::direct_abstract_declarator,
	c_pretty_printer::direct_declarator, c_pretty_printer::declarator):
	Handle BITINT_TYPE.
	(pp_c_integer_constant): Handle printing of large precision wide_ints
	which would buffer overflow digit_buffer.
	* c-warn.cc (conversion_warning, warnings_for_convert_and_check,
	warnings_for_convert_and_check): Handle BITINT_TYPE like
	INTEGER_TYPE.
gcc/c/
	* c-convert.cc (c_convert): Handle BITINT_TYPE like INTEGER_TYPE.
	* c-decl.cc (check_bitfield_type_and_width): Allow BITINT_TYPE
	bit-fields.
	(finish_struct): Prefer to use BITINT_TYPE for BITINT_TYPE bit-fields
	if possible.
	(declspecs_add_type): Formatting fixes.  Handle cts_bitint.  Adjust
	for added union in *specs.  Handle RID_BITINT.
	(finish_declspecs): Handle cts_bitint.  Adjust for added union
	in *specs.
	* c-parser.cc (c_keyword_starts_typename, c_token_starts_declspecs,
	c_parser_declspecs, c_parser_gnu_attribute_any_word): Handle
	RID_BITINT.
	(c_parser_omp_clause_schedule): Handle BITINT_TYPE like INTEGER_TYPE.
	* c-tree.h (enum c_typespec_keyword): Mention _BitInt in comment.
	Add cts_bitint enumerator.
	(struct c_declspecs): Move int_n_idx and floatn_nx_idx into a union
	and add bitint_prec there as well.
	* c-typeck.cc (c_common_type, comptypes_internal):
	Handle BITINT_TYPE.
	(perform_integral_promotions): Promote BITINT_TYPE bit-fields to
	their declared type.
	(build_array_ref, build_unary_op, build_conditional_expr,
	build_c_cast, convert_for_assignment, digest_init, build_binary_op):
	Handle BITINT_TYPE.
	* c-fold.cc (c_fully_fold_internal): Handle BITINT_TYPE like
	INTEGER_TYPE.
	* c-aux-info.cc (gen_type): Handle BITINT_TYPE.
libcpp/
	* expr.cc (interpret_int_suffix): Handle wb and WB suffixes.
	* include/cpplib.h (CPP_N_BITINT): Define.

7 files changed, 308 insertions, 109 deletions

diff --git a/gcc/c/c-aux-info.cc b/gcc/c/c-aux-info.cc
index e33e863..7c1c456 100644
--- a/gcc/c/c-aux-info.cc
+++ b/gcc/c/c-aux-info.cc
@@ -409,6 +409,17 @@ gen_type (const char *ret_val, tree t, formals_style style)
 	    data_type = concat ("unsigned ", data_type, NULL);
 	  break;
 
+	case BITINT_TYPE:
+	  {
+	    char buf[sizeof ("2147483647")];
+	    sprintf (buf, "%d", TYPE_PRECISION (t));
+	    if (TYPE_UNSIGNED (t))
+	      data_type = concat ("unsigned _BitInt(", buf, ")", NULL);
+	    else
+	      data_type = concat ("_BitInt(", buf, ")", NULL);
+	    break;
+	  }
+
 	case OPAQUE_TYPE:
 	case REAL_TYPE:
 	  data_type = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (t)));
diff --git a/gcc/c/c-convert.cc b/gcc/c/c-convert.cc
index 5754d00..71e618c 100644
--- a/gcc/c/c-convert.cc
+++ b/gcc/c/c-convert.cc
@@ -117,6 +117,7 @@ c_convert (tree type, tree expr, bool init_const)
       gcc_fallthrough ();
 
     case INTEGER_TYPE:
+    case BITINT_TYPE:
       if (sanitize_flags_p (SANITIZE_FLOAT_CAST)
 	  && current_function_decl != NULL_TREE
 	  && SCALAR_FLOAT_TYPE_P (TREE_TYPE (expr))
diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
index e611d7a..c9dd135 100644
--- a/gcc/c/c-decl.cc
+++ b/gcc/c/c-decl.cc
@@ -6390,7 +6390,8 @@ check_bitfield_type_and_width (location_t loc, tree *type, tree *width,
   /* Detect invalid bit-field type.  */
   if (TREE_CODE (*type) != INTEGER_TYPE
       && TREE_CODE (*type) != BOOLEAN_TYPE
-      && TREE_CODE (*type) != ENUMERAL_TYPE)
+      && TREE_CODE (*type) != ENUMERAL_TYPE
+      && TREE_CODE (*type) != BITINT_TYPE)
     {
       error_at (loc, "bit-field %qs has invalid type", name);
       *type = unsigned_type_node;
@@ -9330,8 +9331,14 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes,
 	  tree type = TREE_TYPE (field);
 	  if (width != TYPE_PRECISION (type))
 	    {
-	      TREE_TYPE (field)
-		= c_build_bitfield_integer_type (width, TYPE_UNSIGNED (type));
+	      if (TREE_CODE (type) == BITINT_TYPE
+		  && (width > 1 || TYPE_UNSIGNED (type)))
+		TREE_TYPE (field)
+		  = build_bitint_type (width, TYPE_UNSIGNED (type));
+	      else
+		TREE_TYPE (field)
+		  = c_build_bitfield_integer_type (width,
+						   TYPE_UNSIGNED (type));
 	      SET_DECL_MODE (field, TYPE_MODE (TREE_TYPE (field)));
 	    }
 	  DECL_INITIAL (field) = NULL_TREE;
@@ -11546,14 +11553,18 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 			  ("both %<long%> and %<void%> in "
 			   "declaration specifiers"));
 	      else if (specs->typespec_word == cts_int_n)
-		  error_at (loc,
-			    ("both %<long%> and %<__int%d%> in "
-			     "declaration specifiers"),
-			    int_n_data[specs->int_n_idx].bitsize);
+		error_at (loc,
+			  ("both %<long%> and %<__int%d%> in "
+			   "declaration specifiers"),
+			  int_n_data[specs->u.int_n_idx].bitsize);
 	      else if (specs->typespec_word == cts_bool)
 		error_at (loc,
 			  ("both %<long%> and %<_Bool%> in "
 			   "declaration specifiers"));
+	      else if (specs->typespec_word == cts_bitint)
+		error_at (loc,
+			  ("both %<long%> and %<_BitInt%> in "
+			   "declaration specifiers"));
 	      else if (specs->typespec_word == cts_char)
 		error_at (loc,
 			  ("both %<long%> and %<char%> in "
@@ -11566,8 +11577,8 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		error_at (loc,
 			  ("both %<long%> and %<_Float%d%s%> in "
 			   "declaration specifiers"),
-			  floatn_nx_types[specs->floatn_nx_idx].n,
-			  (floatn_nx_types[specs->floatn_nx_idx].extended
+			  floatn_nx_types[specs->u.floatn_nx_idx].n,
+			  (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			   ? "x"
 			   : ""));
 	      else if (specs->typespec_word == cts_dfloat32)
@@ -11606,11 +11617,15 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		error_at (loc,
 			  ("both %<short%> and %<__int%d%> in "
 			   "declaration specifiers"),
-			  int_n_data[specs->int_n_idx].bitsize);
+			  int_n_data[specs->u.int_n_idx].bitsize);
 	      else if (specs->typespec_word == cts_bool)
 		error_at (loc,
 			  ("both %<short%> and %<_Bool%> in "
 			   "declaration specifiers"));
+	      else if (specs->typespec_word == cts_bitint)
+		error_at (loc,
+			  ("both %<short%> and %<_BitInt%> in "
+			   "declaration specifiers"));
 	      else if (specs->typespec_word == cts_char)
 		error_at (loc,
 			  ("both %<short%> and %<char%> in "
@@ -11627,8 +11642,8 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		error_at (loc,
 			  ("both %<short%> and %<_Float%d%s%> in "
 			   "declaration specifiers"),
-			  floatn_nx_types[specs->floatn_nx_idx].n,
-			  (floatn_nx_types[specs->floatn_nx_idx].extended
+			  floatn_nx_types[specs->u.floatn_nx_idx].n,
+			  (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			   ? "x"
 			   : ""));
 	      else if (specs->typespec_word == cts_dfloat32)
@@ -11679,8 +11694,8 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		error_at (loc,
 			  ("both %<signed%> and %<_Float%d%s%> in "
 			   "declaration specifiers"),
-			  floatn_nx_types[specs->floatn_nx_idx].n,
-			  (floatn_nx_types[specs->floatn_nx_idx].extended
+			  floatn_nx_types[specs->u.floatn_nx_idx].n,
+			  (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			   ? "x"
 			   : ""));
 	      else if (specs->typespec_word == cts_dfloat32)
@@ -11731,8 +11746,8 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		error_at (loc,
 			  ("both %<unsigned%> and %<_Float%d%s%> in "
 			   "declaration specifiers"),
-			  floatn_nx_types[specs->floatn_nx_idx].n,
-			  (floatn_nx_types[specs->floatn_nx_idx].extended
+			  floatn_nx_types[specs->u.floatn_nx_idx].n,
+			  (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			   ? "x"
 			   : ""));
               else if (specs->typespec_word == cts_dfloat32)
@@ -11770,6 +11785,10 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		error_at (loc,
 			  ("both %<complex%> and %<_Bool%> in "
 			   "declaration specifiers"));
+	      else if (specs->typespec_word == cts_bitint)
+		error_at (loc,
+			  ("both %<complex%> and %<_BitInt%> in "
+			   "declaration specifiers"));
               else if (specs->typespec_word == cts_dfloat32)
 		error_at (loc,
 			  ("both %<complex%> and %<_Decimal32%> in "
@@ -11809,7 +11828,7 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		  error_at (loc,
 			    ("both %<_Sat%> and %<__int%d%> in "
 			     "declaration specifiers"),
-			    int_n_data[specs->int_n_idx].bitsize);
+			    int_n_data[specs->u.int_n_idx].bitsize);
 	        }
 	      else if (specs->typespec_word == cts_auto_type)
 		error_at (loc,
@@ -11823,6 +11842,10 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		error_at (loc,
 			  ("both %<_Sat%> and %<_Bool%> in "
 			   "declaration specifiers"));
+	      else if (specs->typespec_word == cts_bitint)
+		error_at (loc,
+			  ("both %<_Sat%> and %<_BitInt%> in "
+			   "declaration specifiers"));
 	      else if (specs->typespec_word == cts_char)
 		error_at (loc,
 			  ("both %<_Sat%> and %<char%> in "
@@ -11843,8 +11866,8 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		error_at (loc,
 			  ("both %<_Sat%> and %<_Float%d%s%> in "
 			   "declaration specifiers"),
-			  floatn_nx_types[specs->floatn_nx_idx].n,
-			  (floatn_nx_types[specs->floatn_nx_idx].extended
+			  floatn_nx_types[specs->u.floatn_nx_idx].n,
+			  (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			   ? "x"
 			   : ""));
               else if (specs->typespec_word == cts_dfloat32)
@@ -11882,7 +11905,7 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 	{
 	  /* "void", "_Bool", "char", "int", "float", "double",
 	     "_FloatN", "_FloatNx", "_Decimal32", "__intN",
-	     "_Decimal64", "_Decimal128", "_Fract", "_Accum" or
+	     "_Decimal64", "_Decimal128", "_Fract", "_Accum", "_BitInt(N)" or
 	     "__auto_type".  */
 	  if (specs->typespec_word != cts_none)
 	    {
@@ -11927,7 +11950,7 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 	    case RID_INT_N_1:
 	    case RID_INT_N_2:
 	    case RID_INT_N_3:
-	      specs->int_n_idx = i - RID_INT_N_0;
+	      specs->u.int_n_idx = i - RID_INT_N_0;
 	      if (!in_system_header_at (input_location)
 		  /* If the INT_N type ends in "__", and so is of the format
 		     "__intN__", don't pedwarn.  */
@@ -11935,29 +11958,29 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 			       + (IDENTIFIER_LENGTH (type) - 2), "__", 2) != 0))
 		pedwarn (loc, OPT_Wpedantic,
 			 "ISO C does not support %<__int%d%> types",
-			 int_n_data[specs->int_n_idx].bitsize);
+			 int_n_data[specs->u.int_n_idx].bitsize);
 
 	      if (specs->long_p)
 		error_at (loc,
 			  ("both %<__int%d%> and %<long%> in "
 			   "declaration specifiers"),
-			  int_n_data[specs->int_n_idx].bitsize);
+			  int_n_data[specs->u.int_n_idx].bitsize);
 	      else if (specs->saturating_p)
 		error_at (loc,
 			  ("both %<_Sat%> and %<__int%d%> in "
 			   "declaration specifiers"),
-			  int_n_data[specs->int_n_idx].bitsize);
+			  int_n_data[specs->u.int_n_idx].bitsize);
 	      else if (specs->short_p)
 		error_at (loc,
 			  ("both %<__int%d%> and %<short%> in "
 			   "declaration specifiers"),
-			  int_n_data[specs->int_n_idx].bitsize);
-	      else if (! int_n_enabled_p[specs->int_n_idx])
+			  int_n_data[specs->u.int_n_idx].bitsize);
+	      else if (! int_n_enabled_p[specs->u.int_n_idx])
 		{
 		  specs->typespec_word = cts_int_n;
 		  error_at (loc,
 			    "%<__int%d%> is not supported on this target",
-			    int_n_data[specs->int_n_idx].bitsize);
+			    int_n_data[specs->u.int_n_idx].bitsize);
 		}
 	      else
 		{
@@ -12115,13 +12138,13 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		}
 	      return specs;
 	    CASE_RID_FLOATN_NX:
-	      specs->floatn_nx_idx = i - RID_FLOATN_NX_FIRST;
+	      specs->u.floatn_nx_idx = i - RID_FLOATN_NX_FIRST;
 	      if (!in_system_header_at (input_location))
 		pedwarn_c11 (loc, OPT_Wpedantic,
 			     "ISO C does not support the %<_Float%d%s%> type"
 			     " before C2X",
-			     floatn_nx_types[specs->floatn_nx_idx].n,
-			     (floatn_nx_types[specs->floatn_nx_idx].extended
+			     floatn_nx_types[specs->u.floatn_nx_idx].n,
+			     (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			      ? "x"
 			      : ""));
 
@@ -12129,49 +12152,49 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		error_at (loc,
 			  ("both %<long%> and %<_Float%d%s%> in "
 			   "declaration specifiers"),
-			  floatn_nx_types[specs->floatn_nx_idx].n,
-			  (floatn_nx_types[specs->floatn_nx_idx].extended
+			  floatn_nx_types[specs->u.floatn_nx_idx].n,
+			  (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			   ? "x"
 			   : ""));
 	      else if (specs->short_p)
 		error_at (loc,
 			  ("both %<short%> and %<_Float%d%s%> in "
 			   "declaration specifiers"),
-			  floatn_nx_types[specs->floatn_nx_idx].n,
-			  (floatn_nx_types[specs->floatn_nx_idx].extended
+			  floatn_nx_types[specs->u.floatn_nx_idx].n,
+			  (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			   ? "x"
 			   : ""));
 	      else if (specs->signed_p)
 		error_at (loc,
 			  ("both %<signed%> and %<_Float%d%s%> in "
 			   "declaration specifiers"),
-			  floatn_nx_types[specs->floatn_nx_idx].n,
-			  (floatn_nx_types[specs->floatn_nx_idx].extended
+			  floatn_nx_types[specs->u.floatn_nx_idx].n,
+			  (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			   ? "x"
 			   : ""));
 	      else if (specs->unsigned_p)
 		error_at (loc,
 			  ("both %<unsigned%> and %<_Float%d%s%> in "
 			   "declaration specifiers"),
-			  floatn_nx_types[specs->floatn_nx_idx].n,
-			  (floatn_nx_types[specs->floatn_nx_idx].extended
+			  floatn_nx_types[specs->u.floatn_nx_idx].n,
+			  (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			   ? "x"
 			   : ""));
 	      else if (specs->saturating_p)
 		error_at (loc,
 			  ("both %<_Sat%> and %<_Float%d%s%> in "
 			   "declaration specifiers"),
-			  floatn_nx_types[specs->floatn_nx_idx].n,
-			  (floatn_nx_types[specs->floatn_nx_idx].extended
+			  floatn_nx_types[specs->u.floatn_nx_idx].n,
+			  (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			   ? "x"
 			   : ""));
-	      else if (FLOATN_NX_TYPE_NODE (specs->floatn_nx_idx) == NULL_TREE)
+	      else if (FLOATN_NX_TYPE_NODE (specs->u.floatn_nx_idx) == NULL_TREE)
 		{
 		  specs->typespec_word = cts_floatn_nx;
 		  error_at (loc,
 			    "%<_Float%d%s%> is not supported on this target",
-			    floatn_nx_types[specs->floatn_nx_idx].n,
-			    (floatn_nx_types[specs->floatn_nx_idx].extended
+			    floatn_nx_types[specs->u.floatn_nx_idx].n,
+			    (floatn_nx_types[specs->u.floatn_nx_idx].extended
 			     ? "x"
 			     : ""));
 		}
@@ -12268,6 +12291,63 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 	      pedwarn (loc, OPT_Wpedantic,
 		       "ISO C does not support fixed-point types");
 	      return specs;
+	    case RID_BITINT:
+	      if (specs->long_p)
+		error_at (loc,
+			  ("both %<long%> and %<_BitInt%> in "
+			   "declaration specifiers"));
+	      else if (specs->short_p)
+		error_at (loc,
+			  ("both %<short%> and %<_BitInt%> in "
+			   "declaration specifiers"));
+	      else if (specs->complex_p)
+		error_at (loc,
+			  ("both %<complex%> and %<_BitInt%> in "
+			   "declaration specifiers"));
+	      else if (specs->saturating_p)
+		error_at (loc,
+			  ("both %<_Sat%> and %<_BitInt%> in "
+			   "declaration specifiers"));
+	      else
+		{
+		  specs->typespec_word = cts_bitint;
+		  specs->locations[cdw_typespec] = loc;
+		  specs->u.bitint_prec = -1;
+		  if (error_operand_p (spec.expr))
+		    return specs;
+		  if (TREE_CODE (spec.expr) != INTEGER_CST
+		      || !INTEGRAL_TYPE_P (TREE_TYPE (spec.expr)))
+		    {
+		      error_at (loc, "%<_BitInt%> argument is not an integer "
+				     "constant expression");
+		      return specs;
+		    }
+		  if (tree_int_cst_sgn (spec.expr) <= 0)
+		    {
+		      error_at (loc, "%<_BitInt%> argument %qE is not a "
+				     "positive integer constant expression",
+				spec.expr);
+		      return specs;
+		    }
+		  if (wi::to_widest (spec.expr) > WIDE_INT_MAX_PRECISION - 1)
+		    {
+		      error_at (loc, "%<_BitInt%> argument %qE is larger than "
+				     "%<BITINT_MAXWIDTH%> %qd",
+				spec.expr, (int) WIDE_INT_MAX_PRECISION - 1);
+		      return specs;
+		    }
+		  specs->u.bitint_prec = tree_to_uhwi (spec.expr);
+		  struct bitint_info info;
+		  if (!targetm.c.bitint_type_info (specs->u.bitint_prec,
+						   &info))
+		    {
+		      sorry_at (loc, "%<_BitInt(%d)%> is not supported on "
+				     "this target", specs->u.bitint_prec);
+		      specs->u.bitint_prec = -1;
+		      return specs;
+		    }
+		}
+	      return specs;
 	    default:
 	      /* ObjC reserved word "id", handled below.  */
 	      break;
@@ -12669,12 +12749,12 @@ finish_declspecs (struct c_declspecs *specs)
     case cts_int_n:
       gcc_assert (!specs->long_p && !specs->short_p && !specs->long_long_p);
       gcc_assert (!(specs->signed_p && specs->unsigned_p));
-      if (! int_n_enabled_p[specs->int_n_idx])
+      if (! int_n_enabled_p[specs->u.int_n_idx])
 	specs->type = integer_type_node;
       else
 	specs->type = (specs->unsigned_p
-		       ? int_n_trees[specs->int_n_idx].unsigned_type
-		       : int_n_trees[specs->int_n_idx].signed_type);
+		       ? int_n_trees[specs->u.int_n_idx].unsigned_type
+		       : int_n_trees[specs->u.int_n_idx].signed_type);
       if (specs->complex_p)
 	{
 	  pedwarn (specs->locations[cdw_complex], OPT_Wpedantic,
@@ -12734,12 +12814,12 @@ finish_declspecs (struct c_declspecs *specs)
     case cts_floatn_nx:
       gcc_assert (!specs->long_p && !specs->short_p
 		  && !specs->signed_p && !specs->unsigned_p);
-      if (FLOATN_NX_TYPE_NODE (specs->floatn_nx_idx) == NULL_TREE)
+      if (FLOATN_NX_TYPE_NODE (specs->u.floatn_nx_idx) == NULL_TREE)
 	specs->type = integer_type_node;
       else if (specs->complex_p)
-	specs->type = COMPLEX_FLOATN_NX_TYPE_NODE (specs->floatn_nx_idx);
+	specs->type = COMPLEX_FLOATN_NX_TYPE_NODE (specs->u.floatn_nx_idx);
       else
-	specs->type = FLOATN_NX_TYPE_NODE (specs->floatn_nx_idx);
+	specs->type = FLOATN_NX_TYPE_NODE (specs->u.floatn_nx_idx);
       break;
     case cts_dfloat32:
     case cts_dfloat64:
@@ -12841,6 +12921,22 @@ finish_declspecs (struct c_declspecs *specs)
 			  : accum_type_node;
 	}
       break;
+    case cts_bitint:
+      gcc_assert (!specs->long_p && !specs->short_p
+		  && !specs->complex_p);
+      if (!specs->unsigned_p && specs->u.bitint_prec == 1)
+	{
+	  error_at (specs->locations[cdw_typespec],
+		    "%<signed _BitInt%> argument must be at least 2");
+	  specs->type = integer_type_node;
+	  break;
+	}
+      if (specs->u.bitint_prec == -1)
+	specs->type = integer_type_node;
+      else
+	specs->type = build_bitint_type (specs->u.bitint_prec,
+					 specs->unsigned_p);
+      break;
     default:
       gcc_unreachable ();
     }
diff --git a/gcc/c/c-fold.cc b/gcc/c/c-fold.cc
index adbade4..15ec795 100644
--- a/gcc/c/c-fold.cc
+++ b/gcc/c/c-fold.cc
@@ -379,7 +379,8 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
 	overflow_warning (EXPR_LOC_OR_LOC (expr, input_location), ret, expr);
       if (code == LSHIFT_EXPR
 	  && TREE_CODE (orig_op0) != INTEGER_CST
-	  && TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
+	  && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
+	      || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE)
 	  && TREE_CODE (op0) == INTEGER_CST
 	  && c_inhibit_evaluation_warnings == 0
 	  && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (orig_op0))
@@ -398,6 +399,7 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
 			 ? G_("left shift count is negative")
 			 : G_("right shift count is negative")));
 	  else if ((TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
+		    || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE
 		    || TREE_CODE (TREE_TYPE (orig_op0)) == FIXED_POINT_TYPE)
 		   && compare_tree_int (op1,
 					TYPE_PRECISION (TREE_TYPE (orig_op0)))
@@ -418,11 +420,13 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
       if (code == LSHIFT_EXPR
 	  /* If either OP0 has been folded to INTEGER_CST...  */
 	  && ((TREE_CODE (orig_op0) != INTEGER_CST
-	       && TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
+	       && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
+		   || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE)
 	       && TREE_CODE (op0) == INTEGER_CST)
 	      /* ...or if OP1 has been folded to INTEGER_CST...  */
 	      || (TREE_CODE (orig_op1) != INTEGER_CST
-		  && TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
+		  && (TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
+		      || TREE_CODE (TREE_TYPE (orig_op1)) == BITINT_TYPE)
 		  && TREE_CODE (op1) == INTEGER_CST))
 	  && c_inhibit_evaluation_warnings == 0)
 	/* ...then maybe we can detect an overflow.  */
@@ -435,8 +439,10 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
 	  && TREE_CODE (orig_op1) != INTEGER_CST
 	  && TREE_CODE (op1) == INTEGER_CST
 	  && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
+	      || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE
 	      || TREE_CODE (TREE_TYPE (orig_op0)) == FIXED_POINT_TYPE)
-	  && TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE)
+	  && (TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
+	      || TREE_CODE (TREE_TYPE (orig_op1)) == BITINT_TYPE))
 	warn_for_div_by_zero (loc, op1);
       if (code == MEM_REF
 	  && ret != expr
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index c8d285f..c04962d 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -584,6 +584,7 @@ c_keyword_starts_typename (enum rid keyword)
     case RID_DFLOAT128:
     CASE_RID_FLOATN_NX:
     case RID_BOOL:
+    case RID_BITINT:
     case RID_ENUM:
     case RID_STRUCT:
     case RID_UNION:
@@ -787,6 +788,7 @@ c_token_starts_declspecs (c_token *token)
 	case RID_DFLOAT128:
 	CASE_RID_FLOATN_NX:
 	case RID_BOOL:
+	case RID_BITINT:
 	case RID_ENUM:
 	case RID_STRUCT:
 	case RID_UNION:
@@ -3118,6 +3120,7 @@ c_parser_static_assert_declaration_no_semi (c_parser *parser)
      _Bool
      _Complex
      [_Imaginary removed in C99 TC2]
+     _BitInt ( constant-expression )
      struct-or-union-specifier
      enum-specifier
      typedef-name
@@ -3125,6 +3128,7 @@ c_parser_static_assert_declaration_no_semi (c_parser *parser)
 
    (_Bool and _Complex are new in C99.)
    (atomic-type-specifier is new in C11.)
+   (_BitInt is new in C2X.)
 
    C90 6.5.3, C99 6.7.3, C11 6.7.3:
 
@@ -3401,6 +3405,30 @@ c_parser_declspecs (c_parser *parser, struct c_declspecs *specs,
 	  t = c_parser_typeof_specifier (parser);
 	  declspecs_add_type (loc, specs, t);
 	  break;
+	case RID_BITINT:
+	  if (!typespec_ok)
+	    goto out;
+	  else
+	    {
+	      attrs_ok = true;
+	      seen_type = true;
+	      t.kind = ctsk_resword;
+	      t.spec = c_parser_peek_token (parser)->value;
+	      t.expr = error_mark_node;
+	      t.expr_const_operands = true;
+	      t.has_enum_type_specifier = false;
+	      c_parser_consume_token (parser);
+	      matching_parens parens;
+	      if (parens.require_open (parser))
+		{
+		  c_expr expr = c_parser_expr_no_commas (parser, NULL);
+		  t.expr = convert_lvalue_to_rvalue (loc, expr, true,
+						     true).value;
+		  parens.skip_until_found_close (parser);
+		}
+	      declspecs_add_type (loc, specs, t);
+	    }
+	  break;
 	case RID_ATOMIC:
 	  /* C parser handling of Objective-C constructs needs
 	     checking for correct lvalue-to-rvalue conversions, and
@@ -5049,6 +5077,7 @@ c_parser_gnu_attribute_any_word (c_parser *parser)
 	case RID_DFLOAT128:
 	CASE_RID_FLOATN_NX:
 	case RID_BOOL:
+	case RID_BITINT:
 	case RID_FRACT:
 	case RID_ACCUM:
 	case RID_SAT:
@@ -16308,7 +16337,8 @@ c_parser_omp_clause_schedule (c_parser *parser, tree list)
 	error_at (here,
 		  "schedule %<auto%> does not take "
 		  "a %<chunk_size%> parameter");
-      else if (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE)
+      else if (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE
+	       || TREE_CODE (TREE_TYPE (t)) == BITINT_TYPE)
 	{
 	  /* Attempt to statically determine when the number isn't
 	     positive.  */
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index 7c5234e..f928137 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -270,7 +270,7 @@ enum c_storage_class {
 
 /* A type specifier keyword "void", "_Bool", "char", "int", "float",
    "double", "_Decimal32", "_Decimal64", "_Decimal128", "_Fract", "_Accum",
-   or none of these.  */
+   "_BitInt", or none of these.  */
 enum c_typespec_keyword {
   cts_none,
   cts_void,
@@ -286,6 +286,7 @@ enum c_typespec_keyword {
   cts_floatn_nx,
   cts_fract,
   cts_accum,
+  cts_bitint,
   cts_auto_type
 };
 
@@ -366,11 +367,16 @@ struct c_declspecs {
      specifier, in bytes, or -1 if no such specifiers with nonzero
      alignment.  */
   int align_log;
-  /* For the __intN declspec, this stores the index into the int_n_* arrays.  */
-  int int_n_idx;
-  /* For the _FloatN and _FloatNx declspec, this stores the index into
-     the floatn_nx_types array.  */
-  int floatn_nx_idx;
+  union {
+    /* For the __intN declspec, this stores the index into the int_n_*
+       arrays.  */
+    int int_n_idx;
+    /* For the _FloatN and _FloatNx declspec, this stores the index into
+       the floatn_nx_types array.  */
+    int floatn_nx_idx;
+    /* For _BitInt(N) this stores the N.  */
+    int bitint_prec;
+  } u;
   /* The storage class specifier, or csc_none if none.  */
   enum c_storage_class storage_class;
   /* Any type specifier keyword used such as "int", not reflecting
diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index e6ddf37..5bb9f83 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -413,10 +413,12 @@ composite_type (tree t1, tree t2)
      the composite type.  */
 
   if (code1 == ENUMERAL_TYPE
-      && (code2 == INTEGER_TYPE || code2 == BOOLEAN_TYPE))
+      && (code2 == INTEGER_TYPE
+	  || code2 == BOOLEAN_TYPE))
     return t1;
   if (code2 == ENUMERAL_TYPE
-      && (code1 == INTEGER_TYPE || code1 == BOOLEAN_TYPE))
+      && (code1 == INTEGER_TYPE
+	  || code1 == BOOLEAN_TYPE))
     return t2;
 
   gcc_assert (code1 == code2);
@@ -764,10 +766,10 @@ c_common_type (tree t1, tree t2)
 
   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 	      || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
-	      || code1 == INTEGER_TYPE);
+	      || code1 == INTEGER_TYPE || code1 == BITINT_TYPE);
   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 	      || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
-	      || code2 == INTEGER_TYPE);
+	      || code2 == INTEGER_TYPE || code2 == BITINT_TYPE);
 
   /* When one operand is a decimal float type, the other operand cannot be
      a generic float type or a complex type.  We also disallow vector types
@@ -1004,6 +1006,20 @@ c_common_type (tree t1, tree t2)
     if (mv1 == FLOATNX_TYPE_NODE (i) || mv2 == FLOATNX_TYPE_NODE (i))
       return FLOATNX_TYPE_NODE (i);
 
+  if ((code1 == BITINT_TYPE || code2 == BITINT_TYPE) && code1 != code2)
+    {
+      /* Prefer any other integral types over bit-precise integer types.  */
+      if (TYPE_UNSIGNED (t1) == TYPE_UNSIGNED (t2))
+	return code1 == BITINT_TYPE ? t2 : t1;
+      /* If BITINT_TYPE is unsigned and the other type is signed
+	 non-BITINT_TYPE with the same precision, the latter has higher rank.
+	 In that case:
+	 Otherwise, both operands are converted to the unsigned integer type
+	 corresponding to the type of the operand with signed integer type.  */
+      if (TYPE_UNSIGNED (code1 == BITINT_TYPE ? t1 : t2))
+	return c_common_unsigned_type (code1 == BITINT_TYPE ? t2 : t1);
+    }
+
   /* Otherwise prefer the unsigned one.  */
 
   if (TYPE_UNSIGNED (t1))
@@ -1177,6 +1193,7 @@ comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
     case INTEGER_TYPE:
     case FIXED_POINT_TYPE:
     case REAL_TYPE:
+    case BITINT_TYPE:
       /* With these nodes, we can't determine type equivalence by
 	 looking at what is stored in the nodes themselves, because
 	 two nodes might have different TYPE_MAIN_VARIANTs but still
@@ -2260,12 +2277,17 @@ perform_integral_promotions (tree exp)
   /* ??? This should no longer be needed now bit-fields have their
      proper types.  */
   if (TREE_CODE (exp) == COMPONENT_REF
-      && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
+      && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1)))
+    {
+      if (TREE_CODE (DECL_BIT_FIELD_TYPE (TREE_OPERAND (exp, 1)))
+	  == BITINT_TYPE)
+	return convert (DECL_BIT_FIELD_TYPE (TREE_OPERAND (exp, 1)), exp);
       /* If it's thinner than an int, promote it like a
 	 c_promoting_integer_type_p, otherwise leave it alone.  */
-      && compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
-			   TYPE_PRECISION (integer_type_node)) < 0)
-    return convert (integer_type_node, exp);
+      if (compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
+			    TYPE_PRECISION (integer_type_node)) < 0)
+	return convert (integer_type_node, exp);
+    }
 
   if (c_promoting_integer_type_p (type))
     {
@@ -2790,7 +2812,8 @@ build_array_ref (location_t loc, tree array, tree index)
   if (index == error_mark_node)
     return error_mark_node;
 
-  gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
+  gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE
+	      || TREE_CODE (TREE_TYPE (index)) == BITINT_TYPE);
 
   bool was_vector = VECTOR_TYPE_P (TREE_TYPE (array));
   bool non_lvalue = convert_vector_to_array_for_subscript (loc, &array, index);
@@ -4558,6 +4581,7 @@ build_unary_op (location_t location, enum tree_code code, tree xarg,
 	 associativity, but won't generate any code.  */
       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
 	    || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
+	    || typecode == BITINT_TYPE
 	    || gnu_vector_type_p (TREE_TYPE (arg))))
 	{
 	  error_at (location, "wrong type argument to unary plus");
@@ -4571,6 +4595,7 @@ build_unary_op (location_t location, enum tree_code code, tree xarg,
     case NEGATE_EXPR:
       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
 	    || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
+	    || typecode == BITINT_TYPE
 	    || gnu_vector_type_p (TREE_TYPE (arg))))
 	{
 	  error_at (location, "wrong type argument to unary minus");
@@ -4583,6 +4608,7 @@ build_unary_op (location_t location, enum tree_code code, tree xarg,
     case BIT_NOT_EXPR:
       /* ~ works on integer types and non float vectors. */
       if (typecode == INTEGER_TYPE
+	  || typecode == BITINT_TYPE
 	  || (gnu_vector_type_p (TREE_TYPE (arg))
 	      && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
 	{
@@ -4657,7 +4683,8 @@ build_unary_op (location_t location, enum tree_code code, tree xarg,
     case TRUTH_NOT_EXPR:
       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
 	  && typecode != REAL_TYPE && typecode != POINTER_TYPE
-	  && typecode != COMPLEX_TYPE && typecode != NULLPTR_TYPE)
+	  && typecode != COMPLEX_TYPE && typecode != NULLPTR_TYPE
+	  && typecode != BITINT_TYPE)
 	{
 	  error_at (location,
 		    "wrong type argument to unary exclamation mark");
@@ -4769,7 +4796,7 @@ build_unary_op (location_t location, enum tree_code code, tree xarg,
 
       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
 	  && typecode != INTEGER_TYPE && typecode != REAL_TYPE
-	  && typecode != COMPLEX_TYPE
+	  && typecode != COMPLEX_TYPE && typecode != BITINT_TYPE
 	  && !gnu_vector_type_p (TREE_TYPE (arg)))
 	{
 	  if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
@@ -5351,9 +5378,9 @@ build_conditional_expr (location_t colon_loc, tree ifexp, bool ifexp_bcp,
   if ((TREE_CODE (op1) == EXCESS_PRECISION_EXPR
        || TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
       && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
-	  || code1 == COMPLEX_TYPE)
+	  || code1 == COMPLEX_TYPE || code1 == BITINT_TYPE)
       && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
-	  || code2 == COMPLEX_TYPE))
+	  || code2 == COMPLEX_TYPE || code2 == BITINT_TYPE))
     {
       semantic_result_type = c_common_type (type1, type2);
       if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
@@ -5394,9 +5421,9 @@ build_conditional_expr (location_t colon_loc, tree ifexp, bool ifexp_bcp,
 	result_type = TYPE_MAIN_VARIANT (type1);
     }
   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
-	    || code1 == COMPLEX_TYPE)
+	    || code1 == COMPLEX_TYPE || code1 == BITINT_TYPE)
 	   && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
-	       || code2 == COMPLEX_TYPE))
+	       || code2 == COMPLEX_TYPE || code2 == BITINT_TYPE))
     {
       /* In C11, a conditional expression between a floating-point
 	 type and an integer type should convert the integer type to
@@ -5583,7 +5610,8 @@ build_conditional_expr (location_t colon_loc, tree ifexp, bool ifexp_bcp,
 			  (build_qualified_type (void_type_node, qual));
 	}
     }
-  else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
+  else if (code1 == POINTER_TYPE
+	   && (code2 == INTEGER_TYPE || code2 == BITINT_TYPE))
     {
       if (!null_pointer_constant_p (orig_op2))
 	pedwarn (colon_loc, 0,
@@ -5594,7 +5622,8 @@ build_conditional_expr (location_t colon_loc, tree ifexp, bool ifexp_bcp,
 	}
       result_type = type1;
     }
-  else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
+  else if (code2 == POINTER_TYPE
+	   && (code1 == INTEGER_TYPE || code1 == BITINT_TYPE))
     {
       if (!null_pointer_constant_p (orig_op1))
 	pedwarn (colon_loc, 0,
@@ -6165,7 +6194,8 @@ build_c_cast (location_t loc, tree type, tree expr)
 	warning_at (loc, OPT_Wcast_align,
 		    "cast increases required alignment of target type");
 
-      if (TREE_CODE (type) == INTEGER_TYPE
+      if ((TREE_CODE (type) == INTEGER_TYPE
+	   || TREE_CODE (type) == BITINT_TYPE)
 	  && TREE_CODE (otype) == POINTER_TYPE
 	  && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
       /* Unlike conversion of integers to pointers, where the
@@ -6183,7 +6213,8 @@ build_c_cast (location_t loc, tree type, tree expr)
 		    "to non-matching type %qT", otype, type);
 
       if (TREE_CODE (type) == POINTER_TYPE
-	  && TREE_CODE (otype) == INTEGER_TYPE
+	  && (TREE_CODE (otype) == INTEGER_TYPE
+	      || TREE_CODE (otype) == BITINT_TYPE)
 	  && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
 	  /* Don't warn about converting any constant.  */
 	  && !TREE_CONSTANT (value))
@@ -7135,11 +7166,11 @@ convert_for_assignment (location_t location, location_t expr_loc, tree type,
   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
 	    || codel == FIXED_POINT_TYPE
 	    || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
-	    || codel == BOOLEAN_TYPE)
+	    || codel == BOOLEAN_TYPE || codel == BITINT_TYPE)
 	   && (coder == INTEGER_TYPE || coder == REAL_TYPE
 	       || coder == FIXED_POINT_TYPE
 	       || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
-	       || coder == BOOLEAN_TYPE))
+	       || coder == BOOLEAN_TYPE || coder == BITINT_TYPE))
     {
       if (warnopt && errtype == ic_argpass)
 	maybe_warn_builtin_no_proto_arg (expr_loc, fundecl, parmnum, type,
@@ -7715,7 +7746,9 @@ convert_for_assignment (location_t location, location_t expr_loc, tree type,
       return error_mark_node;
     }
   else if (codel == POINTER_TYPE
-	   && (coder == INTEGER_TYPE || coder == NULLPTR_TYPE))
+	   && (coder == INTEGER_TYPE
+	       || coder == NULLPTR_TYPE
+	       || coder == BITINT_TYPE))
     {
       /* An explicit constant 0 or type nullptr_t can convert to a pointer,
 	 or one that results from arithmetic, even including a cast to
@@ -7756,7 +7789,8 @@ convert_for_assignment (location_t location, location_t expr_loc, tree type,
 
       return convert (type, rhs);
     }
-  else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
+  else if ((codel == INTEGER_TYPE || codel == BITINT_TYPE)
+	   && coder == POINTER_TYPE)
     {
       switch (errtype)
 	{
@@ -8566,7 +8600,8 @@ digest_init (location_t init_loc, tree type, tree init, tree origtype,
 
   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
-      || code == COMPLEX_TYPE || code == VECTOR_TYPE || code == NULLPTR_TYPE)
+      || code == COMPLEX_TYPE || code == VECTOR_TYPE || code == NULLPTR_TYPE
+      || code == BITINT_TYPE)
     {
       tree unconverted_init = inside_init;
       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
@@ -12361,12 +12396,14 @@ build_binary_op (location_t location, enum tree_code code,
     {
     case PLUS_EXPR:
       /* Handle the pointer + int case.  */
-      if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
+      if (code0 == POINTER_TYPE
+	  && (code1 == INTEGER_TYPE || code1 == BITINT_TYPE))
 	{
 	  ret = pointer_int_sum (location, PLUS_EXPR, op0, op1);
 	  goto return_build_binary_op;
 	}
-      else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
+      else if (code1 == POINTER_TYPE
+	       && (code0 == INTEGER_TYPE || code0 == BITINT_TYPE))
 	{
 	  ret = pointer_int_sum (location, PLUS_EXPR, op1, op0);
 	  goto return_build_binary_op;
@@ -12385,7 +12422,8 @@ build_binary_op (location_t location, enum tree_code code,
 	  goto return_build_binary_op;
 	}
       /* Handle pointer minus int.  Just like pointer plus int.  */
-      else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
+      else if (code0 == POINTER_TYPE
+	       && (code1 == INTEGER_TYPE || code1 == BITINT_TYPE))
 	{
 	  ret = pointer_int_sum (location, MINUS_EXPR, op0, op1);
 	  goto return_build_binary_op;
@@ -12407,11 +12445,11 @@ build_binary_op (location_t location, enum tree_code code,
       warn_for_div_by_zero (location, op1);
 
       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
-	   || code0 == FIXED_POINT_TYPE
+	   || code0 == FIXED_POINT_TYPE || code0 == BITINT_TYPE
 	   || code0 == COMPLEX_TYPE
 	   || gnu_vector_type_p (type0))
 	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
-	      || code1 == FIXED_POINT_TYPE
+	      || code1 == FIXED_POINT_TYPE || code1 == BITINT_TYPE
 	      || code1 == COMPLEX_TYPE
 	      || gnu_vector_type_p (type1)))
 	{
@@ -12422,8 +12460,9 @@ build_binary_op (location_t location, enum tree_code code,
 	  if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
 	    tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
 
-	  if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
-	      || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
+	  if (!(((tcode0 == INTEGER_TYPE || tcode0 == BITINT_TYPE)
+		 && (tcode1 == INTEGER_TYPE || tcode1 == BITINT_TYPE))
+		|| (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
 	    resultcode = RDIV_EXPR;
 	  else
 	    /* Although it would be tempting to shorten always here, that
@@ -12439,7 +12478,8 @@ build_binary_op (location_t location, enum tree_code code,
     case BIT_AND_EXPR:
     case BIT_IOR_EXPR:
     case BIT_XOR_EXPR:
-      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
+      if ((code0 == INTEGER_TYPE || code0 == BITINT_TYPE)
+	  && (code1 == INTEGER_TYPE || code1 == BITINT_TYPE))
 	shorten = -1;
       /* Allow vector types which are not floating point types.   */
       else if (gnu_vector_type_p (type0)
@@ -12459,7 +12499,8 @@ build_binary_op (location_t location, enum tree_code code,
 	  && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
 	  && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE)
 	common = 1;
-      else if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
+      else if ((code0 == INTEGER_TYPE || code0 == BITINT_TYPE)
+	       && (code1 == INTEGER_TYPE || code1 == BITINT_TYPE))
 	{
 	  /* Although it would be tempting to shorten always here, that loses
 	     on some targets, since the modulo instruction is undefined if the
@@ -12477,10 +12518,12 @@ build_binary_op (location_t location, enum tree_code code,
     case TRUTH_XOR_EXPR:
       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
 	   || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
-	   || code0 == FIXED_POINT_TYPE || code0 == NULLPTR_TYPE)
+	   || code0 == FIXED_POINT_TYPE || code0 == NULLPTR_TYPE
+	   || code0 == BITINT_TYPE)
 	  && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
 	      || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
-	      || code1 == FIXED_POINT_TYPE || code1 ==  NULLPTR_TYPE))
+	      || code1 == FIXED_POINT_TYPE || code1 == NULLPTR_TYPE
+	      || code1 == BITINT_TYPE))
 	{
 	  /* Result of these operations is always an int,
 	     but that does not mean the operands should be
@@ -12543,9 +12586,10 @@ build_binary_op (location_t location, enum tree_code code,
 	  converted = 1;
 	}
       else if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE
+		|| code0 == BITINT_TYPE
 		|| (gnu_vector_type_p (type0)
 		    && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE))
-	       && code1 == INTEGER_TYPE)
+	       && (code1 == INTEGER_TYPE || code1 == BITINT_TYPE))
 	{
 	  doing_shift = true;
 	  if (TREE_CODE (op1) == INTEGER_CST)
@@ -12603,9 +12647,10 @@ build_binary_op (location_t location, enum tree_code code,
 	  converted = 1;
 	}
       else if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE
+		|| code0 == BITINT_TYPE
 		|| (gnu_vector_type_p (type0)
 		    && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE))
-	       && code1 == INTEGER_TYPE)
+	       && (code1 == INTEGER_TYPE || code1 == BITINT_TYPE))
 	{
 	  doing_shift = true;
 	  if (TREE_CODE (op0) == INTEGER_CST
@@ -12719,9 +12764,10 @@ build_binary_op (location_t location, enum tree_code code,
       /* Result of comparison is always int,
 	 but don't convert the args to int!  */
       build_type = integer_type_node;
-      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
+      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == BITINT_TYPE
 	   || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
 	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
+	      || code1 == BITINT_TYPE
 	      || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
 	short_compare = 1;
       else if (code0 == POINTER_TYPE
@@ -12782,12 +12828,14 @@ build_binary_op (location_t location, enum tree_code code,
 			      (build_qualified_type (void_type_node, qual));
 	    }
 	}
-      else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
+      else if (code0 == POINTER_TYPE
+	       && (code1 == INTEGER_TYPE || code1 == BITINT_TYPE))
 	{
 	  result_type = type0;
 	  pedwarn (location, 0, "comparison between pointer and integer");
 	}
-      else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
+      else if ((code0 == INTEGER_TYPE || code0 == BITINT_TYPE)
+	       && code1 == POINTER_TYPE)
 	{
 	  result_type = type1;
 	  pedwarn (location, 0, "comparison between pointer and integer");
@@ -12875,9 +12923,9 @@ build_binary_op (location_t location, enum tree_code code,
         }
       build_type = integer_type_node;
       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
-	   || code0 == FIXED_POINT_TYPE)
+	   || code0 == BITINT_TYPE || code0 == FIXED_POINT_TYPE)
 	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
-	      || code1 == FIXED_POINT_TYPE))
+	      || code1 == BITINT_TYPE || code1 == FIXED_POINT_TYPE))
 	short_compare = 1;
       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
 	{
@@ -12936,12 +12984,14 @@ build_binary_op (location_t location, enum tree_code code,
 	    warning_at (location, OPT_Wextra,
 			"ordered comparison of pointer with integer zero");
 	}
-      else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
+      else if (code0 == POINTER_TYPE
+	       && (code1 == INTEGER_TYPE || code1 == BITINT_TYPE))
 	{
 	  result_type = type0;
 	  pedwarn (location, 0, "comparison between pointer and integer");
 	}
-      else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
+      else if ((code0 == INTEGER_TYPE || code0 == BITINT_TYPE)
+	       && code1 == POINTER_TYPE)
 	{
 	  result_type = type1;
 	  pedwarn (location, 0, "comparison between pointer and integer");
@@ -12995,12 +13045,11 @@ build_binary_op (location_t location, enum tree_code code,
     }
 
   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
-       || code0 == FIXED_POINT_TYPE
+       || code0 == FIXED_POINT_TYPE || code0 == BITINT_TYPE
        || gnu_vector_type_p (type0))
-      &&
-      (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
-       || code1 == FIXED_POINT_TYPE
-       || gnu_vector_type_p (type1)))
+      && (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
+	  || code1 == FIXED_POINT_TYPE || code1 == BITINT_TYPE
+	  || gnu_vector_type_p (type1)))
     {
       bool first_complex = (code0 == COMPLEX_TYPE);
       bool second_complex = (code1 == COMPLEX_TYPE);