Re: [PATCH 0/12] GCC _BitInt support [PR102989]

[Joseph Myers <joseph@codesourcery.com>]

On Wed, 9 Aug 2023, Jakub Jelinek via Gcc-patches wrote:

> - _Complex _BitInt(N) isn't supported; again mainly because none of the psABIs
>   mention how those should be passed/returned; in a limited way they are
>   supported internally because the internal functions into which
>   __builtin_{add,sub,mul}_overflow{,_p} is lowered return COMPLEX_TYPE as a
>   hack to return 2 values without using references/pointers

What happens when the usual arithmetic conversions are applied to 
operands, one of which is a complex integer type and the other of which is 
a wider _BitInt type?  I don't see anything in the code to disallow this 
case (which would produce an expression with a _Complex _BitInt type), or 
any testcases for it.

Other testcases I think should be present (along with any corresponding 
changes needed to the code itself):

* Verifying that the new integer constant suffix is rejected for C++.

* Verifying appropriate pedwarn-if-pedantic for the new constant suffix 
for versions of C before C2x (and probably for use of _BitInt type 
specifiers before C2x as well) - along with the expected -Wc11-c2x-compat 
handling (in C2x mode) / -pedantic -Wno-c11-c2x-compat in older modes.

-- 
Joseph S. Myers
joseph@codesourcery.com