clang is not happy about it:

Died at ./regress/run_test.pl line 796.
 ./regress/core/quantize_coordinates .. failed (psql exited with an error: /tmp/pgis_reg/test_45_out)
-----------------------------------------------------------------------------
t1|t
psql:quantize_coordinates.sql:4: ERROR:  Must specify precision
t3|t
t4|t
t5|t
psql:quantize_coordinates.sql:14: server closed the connection unexpectedly
make: *** [regress/runtest.mk:24: check-regress] Error 2
	This probably means the server terminated abnormally
	before or while processing the request.
psql:quantize_coordinates.sql:14: error: connection to server was lost
-----------------------------------------------------------------------------

clang is not happy about it:

ok, issue solved by adding a int cast in the expression (int)((dint >> 52) & 2047) - 1023; otherwise I suspect the sanitizer flag would complain about unsigned integer underflow when computing negative exponents.

@Komzpa @pramsey @rouault What's your thought about backporting to 3.3 as well. Seems change is harmless enough. I'll push to 3.4 (master) once the PG16 new GHA docker build is done.

Seems change is harmless enough.

Personnally I wouldn't backport this. This is really in the enhancement category, and it might change a bit results. I believe the new implementation is less pessimistic than the previous one (that is to say the number of nullified bits can be a bit higher, while meeting the expressed precision), so this will result in slightly different results.