[56/77] Use the more specific type when two modes are known to be equal

[56/77] Use the more specific type when two modes are known to be equal

This patch adjusts a couple of cases in which we had established
that two modes were equal and happened to be using the one with the
more general type instead of the one with the more specific type.

2017-08-30  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* expr.c (expand_expr_real_2): Use word_mode instead of innermode
	when the two are known to be equal.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r251508