PR bootstrap/39454
	* cse.c (fold_rtx): Don't modify original const_arg1 when
	canonicalizing SHIFT_COUNT_TRUNCATED shift count, do it on a
	separate variable instead.
	* rtlanal.c (nonzero_bits1) <case ASHIFTRT>: Don't assume anything
	from out of range shift counts.
	(num_sign_bit_copies1) <case ASHIFTRT, case ASHIFT>: Similarly.

From-SVN: r144857