PR target/69442
	* combine.c (combine_instructions): For REG_EQUAL note with
	SET_DEST being ZERO_EXTRACT, also temporarily set SET_DEST
	to the underlying register.
	* doc/rtl.texi (REG_EQUAL): Document the behavior of
	REG_EQUAL/REG_EQUIV notes if SET_DEST is ZERO_EXTRACT.

	* gcc.dg/pr69442.c: New test.

From-SVN: r232819