[Bug c/108580] gcc treats shifts as signed operation, does wrong promotion

["postmaster at raasu dot org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108580

--- Comment #8 from postmaster at raasu dot org ---
I know enough C that you can't write code like:

int i = 0xFFFFFFFF;

This is not equal to:

int i = -1;

or

int i = (-1);


---
Largest literal you can assign to "int" is "0x7FFFFFFF". Any larger value must
be either result of expression or another variable, otherwise it will result in
"arithmetic" overflow warning.

Some literals and operations are inherently unsigned, no matter what generic
rules say. As I already said, writing "1u << bits" would be incorrect, and
strict-conforming or "pedantic" compiler would throw warning as the types don't
match and implicit conversion doesn't happen with sizes larger than 32 bits.
Type modifiers are otherwise case-insensitive, but don't support mixed-case.

C standard doesn't even mention anything about "size_t" or have type modifier
for it. Even though printf() and alike support "%z", it is considered extension
and will be rejected when using strict/pedantic mode.