c: Diagnose char argument to __builtin_stdc_*

When working on __builtin_stdc_rotate_*, I've noticed that while the
second argument to those is explicitly allowed to have char type,
the first argument to all the stdc_* type-generic functions is
- standard unsigned integer type, excluding bool;
- extended unsigned integer type;
- or, bit-precise unsigned integer type whose width matches a standard
  or extended integer type, excluding bool.
but the __builtin_stdc_* lowering code was diagnosing just
!INTEGRAL_TYPE_P
ENUMERAL_TYPE
BOOLEAN_TYPE
!TYPE_UNSIGNED
Now, with -funsigned-char plain char type is TYPE_UNSIGNED, yet it isn't
allowed because it isn't standard unsigned integer type, nor
extended unsigned integer type, nor bit-precise unsigned integer type.

The following patch diagnoses char arguments and adds testsuite coverage
for that.

Or should I make it a pedwarn instead?

2024-10-30  Jakub Jelinek  <jakub@redhat.com>

gcc/c/
	* c-parser.cc (c_parser_postfix_expression): Diagnose if
	first __builtin_stdc_* argument has char type even when
	-funsigned-char.
gcc/testsuite/
	* gcc.dg/builtin-stdc-bit-3.c: New test.
	* gcc.dg/builtin-stdc-rotate-3.c: New test.

0 files changed, 0 insertions, 0 deletions