Hi,

gimple_set_location is mostly invoked on newly built GIMPLE statements, so 
their location is UNKNOWN_LOCATION and setting it will clobber the warning 
data of the passed location, if any.

Tested on x86-64/Linux, OK for mainline and 12 branch?


2022-06-10  Eric Botcazou  <ebotcazou@adacore.com>

	* gimple.h (gimple_set_location): Do not copy warning data from
	the previous location when it is UNKNOWN_LOCATION.


2022-06-10  Eric Botcazou  <ebotcazou@adacore.com>

testsuite/
	* c-c++-common/nonnull-1.c: Remove XFAIL for C++.

-- 
Eric Botcazou