Re: [PATCH 3/3] function: Restructure *logue insertion

[Jeff Law <law@redhat.com>]

On 05/16/2016 07:09 PM, Segher Boessenkool wrote:
> This patch restructures how the prologues/epilogues are inserted.  Sibcalls
> that run without prologue are now handled in shrink-wrap.c; it communicates
> what is already handled by setting the EDGE_IGNORE flag.  The
> try_shrink_wrapping function then doesn't need to be passed the bb_flags
> anymore.
>
> Tested like the previous two patches; is this okay for trunk?
>
>
> Segher
>
>
> 2016-05-16  Segher Boessenkool  <segher@kernel.crashing.org>
>
> 	* function.c (make_epilogue_seq): Remove epilogue_end parameter.
> 	(thread_prologue_and_epilogue_insns): Remove bb_flags.  Restructure
> 	code.  Ignore sibcalls on EDGE_IGNORE edges.
> 	* shrink-wrap.c (handle_simple_exit): New function.  Set EDGE_IGNORE
> 	on edges for sibcalls that run without prologue.  The rest of the
> 	function is combined from...
> 	(fix_fake_fallthrough_edge): ... this, and ...
> 	(try_shrink_wrapping): ... a part of this.  Remove the bb_with
> 	function argument, make it a local variable.
For some reason I found this patch awful to walk through.  In 
retrospect, it might have been better break this down further. Not 
because it's conceptually difficult to follow, but because the diffs 
themselves are difficult to read.

I kept slicing out hunks when I could pair up the original code to its 
new functional equivalent and hunks which were just "fluff" and kept 
iterating until there was nothing left that seemed unreasonable.

OK for the trunk, but please watch closely for any fallout.

jeff