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Cc: Dale Johannesen <dalej@apple.com>
From: Dale Johannesen <dalej@apple.com>
Subject: [tree-ssa vs lno] who is right?
Date: Fri, 26 Mar 2004 05:32:00 -0000
To: "gcc@gcc.gnu.org list" <gcc@gcc.gnu.org>
X-SW-Source: 2004-03/txt/msg01531.txt.bz2

When the LNO branch copies a loop, it attempts to fix up the phi nodes 
with
an algorithm that assumes there is only one phi per block per variable. 
  That is, it
won't see code like this:

;; basic block 19, loop depth 0, count 0
;; prev block 9, next block 20
;; pred:       10 [100.0%]  (fallthru)
;; succ:       28 [50.0%]  (true,exec) 29 [50.0%]  (false,exec)
# maxmin_Result_140 = PHI <1(10)>;
# maxmin_Result_142 = PHI <2(10)>;
# lsm_tmp.19_144 = PHI <lsm_tmp.19_84(10)>;
<L28>:;
if (m__10 == 0) goto <L26>; else goto <L27>;

Is that suppose to be a valid assumption?  The dup is created by 
copyrename, and
I see no code there that's intended to stop dups from being created (on 
the
contrary, but surely it's unusual for the live ranges to overlap).