builtins: Avoid ICE with __builtin_clear_padding on POINTERS_EXTEND_UNSIGNED targets...

builtins: Avoid ICE with __builtin_clear_padding on POINTERS_EXTEND_UNSIGNED targets [PR98147]

The function that calls targetm.emit_call_builtin___clear_cache
asserts that each of the begin and end operands has either ptr_mode or
Pmode.
On most targets that is the same mode, but e.g. on aarch64 -mabi=ilp32
or a few others it is different.  When a target has a clear cache
non-library handler, it will use create_address_operand which will do the
conversion to the right mode automatically, but when emitting a library
call, we just say the operands are ptr_mode even when they can be Pmode
too; in that case we need to convert explicitly.

2020-12-07  Jakub Jelinek  <jakub@redhat.com>

	PR target/98147
	* builtins.c (default_emit_call_builtin___clear_cache): Call
	convert_memory_address to ptr_mode on both begin and end.

	* gcc.dg/pr98147.c: New test.