Pull in r191165 from upstream llvm trunk:

  ISelDAG: spot chain cycles involving MachineNodes

  Previously, the DAGISel function WalkChainUsers was spotting that it
  had entered already-selected territory by whether a node was a
  MachineNode (amongst other things). Since it's fairly common practice
  to insert MachineNodes during ISelLowering, this was not the correct
  check.

  Looking around, it seems that other nodes get their NodeId set to -1
  upon selection, so this makes sure the same thing happens to all
  MachineNodes and uses that characteristic to determine whether we
  should stop looking for a loop during selection.

  This should fix PR15840.

Specifically, this fixes the long-standing assertion failure when
compiling the multimedia/gstreamer port on i386.  Thanks to Tijl
Coosemans for his help in getting upstream to fix it.

Approved by:	re (marius)

1 files changed, 5 insertions, 5 deletions

diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 8b110e3..9935626 100644
--- a/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -1736,15 +1736,15 @@ WalkChainUsers(const SDNode *ChainedNode,
 
     SDNode *User = *UI;
 
+    if (User->getOpcode() == ISD::HANDLENODE)  // Root of the graph.
+      continue;
+
     // If we see an already-selected machine node, then we've gone beyond the
     // pattern that we're selecting down into the already selected chunk of the
     // DAG.
-    if (User->isMachineOpcode() ||
-        User->getOpcode() == ISD::HANDLENODE)  // Root of the graph.
-      continue;
-
     unsigned UserOpcode = User->getOpcode();
-    if (UserOpcode == ISD::CopyToReg ||
+    if (User->isMachineOpcode() ||
+        UserOpcode == ISD::CopyToReg ||
         UserOpcode == ISD::CopyFromReg ||
         UserOpcode == ISD::INLINEASM ||
         UserOpcode == ISD::EH_LABEL ||