comment tweaks

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@199750 138bc75d-0d04-0410-961f-82ee72b054a4
	* config/arm/arm.c (arm_r3_live_at_start_p): New predicate.
	(arm_compute_static_chain_stack_bytes): Use it.  Tidy up.
	(arm_expand_prologue): Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@199752 138bc75d-0d04-0410-961f-82ee72b054a4