combine: Fix problem with RTL checking

combine: Fix problem with RTL checking

As Jakub found, after my recent combine patch at least on x86 problems
show up with RTL checking enabled.  This is because the I2 generated
by a successful instruction combination can write not only a register
but it can also write a paradoxical subreg of one.

This fixes it.

	* combine.c (try_combine): When adjusting LOG_LINKS for the destination
	that moved to I2, also allow destinations that are a paradoxical
	subreg (instead of a normal reg).

From-SVN: r257736