[PATCH GCC][2/7]Don't rename variables for deleted new preheader

[Bin Cheng]

Hi,
I noticed that new_preheader basic block could be deleted if the copied
loop is added at entry in function slpeel_tree_duplicate_loop_to_edge_cfg.
This simple patch skips new_preheader during variable renaming if it is
deleted.
Bootstrap and test in patch set on x86_64 and AArch64, is it OK?

Thanks,
bin
2017-10-04  Bin Cheng  <bin.ch...@arm.com>

        * tree-vect-loop-manip.c (slpeel_tree_duplicate_loop_to_edge_cfg): Skip
        renaming variables in new preheader if it's deleted.
From 9c7719402c9528b517d8408419c2e9b930708772 Mon Sep 17 00:00:00 2001
From: Bin Cheng <binch...@e108451-lin.cambridge.arm.com>
Date: Fri, 22 Sep 2017 16:50:40 +0100
Subject: [PATCH 2/7] skip-new_preheader.txt

---
 gcc/tree-vect-loop-manip.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
index f78e4b4..2c724a2 100644
--- a/gcc/tree-vect-loop-manip.c
+++ b/gcc/tree-vect-loop-manip.c
@@ -496,7 +496,8 @@ slpeel_tree_duplicate_loop_to_edge_cfg (struct loop *loop,
 			       loop_preheader_edge (new_loop)->src);
     }
 
-  for (unsigned i = 0; i < scalar_loop->num_nodes + 1; i++)
+  /* Skip new preheader since it's deleted if copy loop is added at entry.  */
+  for (unsigned i = (at_exit ? 0 : 1); i < scalar_loop->num_nodes + 1; i++)
     rename_variables_in_bb (new_bbs[i], duplicate_outer_loop);
 
   if (scalar_loop != loop)
-- 
1.9.1