Re: Fix PR 65177: diamonds are not valid execution threads for jump threading

[Jeff Law <law at redhat dot com>]

On 03/19/15 13:54, Sebastian Pop wrote:
> Richard Biener wrote:
> > >please instead fixup after copy_bbs in duplicate_seme_region.
> > >
> Thanks for the review.
> Attached patch that does not modify copy_bbs.
> Fixes make check in hmmer and make check RUNTESTFLAGS=tree-ssa.exp
>
> Full bootstrap and regtest in progress on x86_64-linux.  Ok for trunk?
>
>
> 0001-diamonds-are-not-valid-execution-threads-for-jump-th.patch
>
>
>  From 8f1516235bce3e1c4f359149dcc546d813ed7817 Mon Sep 17 00:00:00 2001
> From: Sebastian Pop<sebpop@gmail.com>
> Date: Tue, 17 Mar 2015 20:28:19 +0100
> Subject: [PATCH] diamonds are not valid execution threads for jump threading
>
> 	PR tree-optimization/65177
> 	* tree-ssa-threadupdate.c (verify_seme): Renamed verify_jump_thread.
> 	(bb_in_bbs): New.
> 	(duplicate_seme_region): Renamed duplicate_thread_path.  Redirect all
> 	edges not adjacent on the path to the original code.
OK for the trunk.  Though I think there's some stage1 refactoring that 
we're going to want to do.

Specifically, it seems to me that copy_bbs should be refactored into 
copy_bbs and copy_bbs_for_threading or somesuch.  Where those routines 
call into refactored common subroutines, but obviously handle wiring up 
the outgoing edges from the copied blocks differently.

The goal would be to eliminate the overly complex block copy/CFG update 
scheme in tree-ssa-threadupdate.c as part of a larger project to convert 
to a backward threader that can run independently of DOM.

Jeff