Re: UBSAN-safe way to convert from unsigned int to int

[Alexander Monakov via Gcc-help <gcc-help@xxxxxxxxxxx>]

On Tue, 20 May 2025, Florian Weimer via Gcc-help wrote:

> Is there a concise way to convert X to a value Y of type int, so that
> 
>   X == (unsigned int) Y
> 
> (assuming that X is of type unsigned int to start with)?  GCC supports
> this as an extension, using Y = (int) X, but this extension is
> apparently unavailable if UBSAN is active.

Can you give a specific compilable example? Neither GCC nor Clang instruments

int f(unsigned x)
{
	return x;
}

under -fsanitize=undefined.

Alexander