Change the scheduler from adding nodes in allnodes order

to adding them in a determinstic order (bottom up from 
the root) based on the structure of the graph itself.

This updates tests for some random changes, interesting
bits: CodeGen/Blackfin/promote-logic.ll no longer crashes.
I have no idea why, but that's good right?

CodeGen/X86/2009-07-16-LoadFoldingBug.ll also fails, but
now compiles to have one fewer constant pool entry, making
the expected load that was being folded disappear.  Since it
is an unreduced mass of gnast, I just removed it.

This fixes PR6370


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97023 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 2 deletions

diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index b51c61bf6d..06e7b8c905 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -218,8 +218,20 @@ void ScheduleDAGSDNodes::BuildSchedUnits() {
   // Check to see if the scheduler cares about latencies.
   bool UnitLatencies = ForceUnitLatencies();
 
-  for (SelectionDAG::allnodes_iterator NI = DAG->allnodes_begin(),
-       E = DAG->allnodes_end(); NI != E; ++NI) {
+  // Add all nodes in depth first order.
+  SmallVector<SDNode*, 64> Worklist;
+  SmallPtrSet<SDNode*, 64> Visited;
+  Worklist.push_back(DAG->getRoot().getNode());
+  Visited.insert(DAG->getRoot().getNode());
+  
+  while (!Worklist.empty()) {
+    SDNode *NI = Worklist.pop_back_val();
+    
+    // Add all operands to the worklist unless they've already been added.
+    for (unsigned i = 0, e = NI->getNumOperands(); i != e; ++i)
+      if (Visited.insert(NI->getOperand(i).getNode()))
+        Worklist.push_back(NI->getOperand(i).getNode());
+  
     if (isPassiveNode(NI))  // Leaf node, e.g. a TargetImmediate.
       continue;