[llvm] r176636 - pre-RA-sched assertion fix. This bug was exposed by r176037.

[Andrew Trick]

Author: atrick
Date: Thu Mar  7 13:07:57 2013
New Revision: 176636

URL: http://llvm.org/viewvc/llvm-project?rev=176636&view=rev
Log:
pre-RA-sched assertion fix. This bug was exposed by r176037.

rdar:13370002 [pre-RA-sched] assertion: released too many times

I tracked this down to an earlier hack that is no longer applicable
and interfered with normal scheduler logic. With the changes in
r176037, it was causing an instruction to be scheduled multiple times.

I have an external test case that I tried hard to reduce and
failed. I can't even reproduce with llc.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp?rev=176636&r1=176635&r2=176636&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp Thu Mar  7 13:07:57 2013
@@ -904,9 +904,6 @@ void ScheduleDAGRRList::BacktrackBottomU
   SUnit *OldSU = Sequence.back();
   while (true) {
     Sequence.pop_back();
-    if (SU->isSucc(OldSU))
-      // Don't try to remove SU from AvailableQueue.
-      SU->isAvailable = false;
     // FIXME: use ready cycle instead of height
     CurCycle = OldSU->getHeight();
     UnscheduleNodeBottomUp(OldSU);