[Patch, testsuite, mips] Fix two failing MIPS tests.

[Richard Sandiford]

"Steve Ellcey " <sellcey@mips.com> writes:
> Two MIPS specific tests started failing a few days ago, this patch fixes
> them.  The tests are trying to check that a performance optimization is
> done and that one constant is derived from another and not simply loaded
> as a completely new constant.
>
> Post 4.9 changes have affected which constant gets loaded and which one
> gets derived (and how it is derived) from it.  The new code looks as
> good as the old code:
>
> Old:
>
>  	li	$5,305397760			# 0x12340000
>  	addiu	$4,$5,1
>  	addiu	$5,$5,-1
>
> New:
>
> 	li	$5,305332224			# 0x12330000
>  	ori	$5,$5,0xffff
>  	addiu	$4,$5,2

This isn't as good though -- $4 now depends on two previous
instructions.  Do you know which specific change was responsible?

Thanks,
Richard