[PATCH][AArch64] Improve SHA1 scheduling

[James Greenhalgh]

On Tue, Dec 06, 2016 at 03:10:50PM +0000, Wilco Dijkstra wrote:
> Â    
> 
> ping

I haven't seen a follow-up to Andrew's point regarding other
read-modify-write operations.

Did youi investigate the cost of these?

James

> 
> 
> From: Wilco Dijkstra
> Sent: 25 October 2016 18:08
> To: GCC Patches
> Cc: nd
> Subject: [PATCH][AArch64] Improve SHA1 scheduling
> Â Â Â  
> SHA1H instructions may be scheduled after a SHA1C instruction
> that uses the same input register.  However SHA1C updates its input,
> so if SHA1H is scheduled after it, it requires an extra move.
> Increase the priority of SHA1H to ensure it gets scheduled
> earlier, avoiding the move.
> 
> Is this something the generic scheduler could do automatically for
> instructions with RMW operands?
> 
> Passes bootstrap & regress. OK for commit?
> 
> ChangeLog:
> 2016-10-25  Wilco Dijkstra  <wdijkstr@arm.com>
> 
> Â Â Â Â Â Â Â  * config/aarch64/aarch64.c (aarch64_sched_adjust_priority)
> Â Â Â Â Â Â Â  New function.
> Â Â Â Â Â Â Â  (TARGET_SCHED_ADJUST_PRIORITY): Define target hook.
 Â Â Â Â Â Â Â