My understanding is that GCC's preferred null value for rtx is NULL_RTX
(and for tree is NULL_TREE), and by being typed allows strict type checking,
and use with function polymorphism and template instantiation.
C++'s nullptr is preferred over NULL and 0 for pointer types that don't
have a defined null of the correct type.

This minor clean-up uses NULL_RTX consistently in i386-expand.cc.

This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
and make -k check, both with and without --target_board=unix{-m32}
with no new failures.  Ok for mainline?  Is my understanding correct?


2023-05-24  Roger Sayle  <roger@nextmovesoftware.com>

gcc/ChangeLog
	* config/i386/i386.cc (ix86_convert_wide_int_to_broadcast):  Use
	NULL_RTX instead of nullptr.
	(ix86_convert_const_wide_int_to_broadcast): Likewise.
	(ix86_broadcast_from_constant): Likewise.
	(ix86_expand_vector_move): Likewise.
	(ix86_extract_perm_from_pool_constant): Likewise.


Thanks,
Roger
--