MFC r265925:

Upgrade our copy of llvm/clang to 3.4.1 release.  This release contains
mostly fixes, for the following upstream bugs:

http://llvm.org/PR16365 http://llvm.org/PR17473 http://llvm.org/PR18000
http://llvm.org/PR18068 http://llvm.org/PR18102 http://llvm.org/PR18165
http://llvm.org/PR18260 http://llvm.org/PR18290 http://llvm.org/PR18316
http://llvm.org/PR18460 http://llvm.org/PR18473 http://llvm.org/PR18515
http://llvm.org/PR18526 http://llvm.org/PR18600 http://llvm.org/PR18762
http://llvm.org/PR18773 http://llvm.org/PR18860 http://llvm.org/PR18994
http://llvm.org/PR19007 http://llvm.org/PR19010 http://llvm.org/PR19033
http://llvm.org/PR19059 http://llvm.org/PR19144 http://llvm.org/PR19326

1 files changed, 6 insertions, 1 deletions

diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index 054e3dd..c1893c9 100644
--- a/contrib/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/contrib/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -219,8 +219,11 @@ void ScheduleDAGSDNodes::ClusterNeighboringLoads(SDNode *Node) {
   DenseMap<long long, SDNode*> O2SMap;  // Map from offset to SDNode.
   bool Cluster = false;
   SDNode *Base = Node;
+  // This algorithm requires a reasonably low use count before finding a match
+  // to avoid uselessly blowing up compile time in large blocks.
+  unsigned UseCount = 0;
   for (SDNode::use_iterator I = Chain->use_begin(), E = Chain->use_end();
-       I != E; ++I) {
+       I != E && UseCount < 100; ++I, ++UseCount) {
     SDNode *User = *I;
     if (User == Node || !Visited.insert(User))
       continue;
@@ -237,6 +240,8 @@ void ScheduleDAGSDNodes::ClusterNeighboringLoads(SDNode *Node) {
     if (Offset2 < Offset1)
       Base = User;
     Cluster = true;
+    // Reset UseCount to allow more matches.
+    UseCount = 0;
   }
 
   if (!Cluster)