[llvm] r324797 - [DAG] Make early exit hasPredecessorHelper return true. NFCI.

[Nirav Dave via llvm-commits]

Author: niravd
Date: Fri Feb  9 18:41:22 2018
New Revision: 324797

URL: http://llvm.org/viewvc/llvm-project?rev=324797&view=rev
Log:
[DAG] Make early exit hasPredecessorHelper return true. NFCI.

All uses conservatively assume in early exit case that it will be a
predecessor. Changing default removes checking code in all uses.

Modified:
    llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
    llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp

Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h?rev=324797&r1=324796&r2=324797&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h Fri Feb  9 18:41:22 2018
@@ -842,6 +842,9 @@ public:
     }
     // Push deferred nodes back on worklist.
     Worklist.append(DeferredNodes.begin(), DeferredNodes.end());
+    // If we bailed early, conservatively return found.
+    if (MaxSteps != 0 && Visited.size() >= MaxSteps)
+        return true;
     return Found;
   }
 

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp?rev=324797&r1=324796&r2=324797&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp Fri Feb  9 18:41:22 2018
@@ -2430,9 +2430,6 @@ HandleMergeInputChains(SmallVectorImpl<S
   for (auto *N : ChainNodesMatched)
     if (SDNode::hasPredecessorHelper(N, Visited, Worklist, Max, true))
       return SDValue();
-  // Fail conservatively if we stopped searching early.
-  if (Visited.size() >= Max)
-    return SDValue();
 
   // Return merged chain.
   if (InputChains.size() == 1)

Modified: llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp?rev=324797&r1=324796&r2=324797&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp Fri Feb  9 18:41:22 2018
@@ -2117,10 +2117,10 @@ static bool isFusableLoadOpStorePattern(
     // this search by visiting the uses and make sure they all have
     // smaller node id than the load.
 
-    bool FoundLoad = false;
-    SmallVector<SDValue, 4> ChainOps;
-    SmallVector<const SDNode *, 4> LoopWorklist;
-    SmallPtrSet<const SDNode *, 16> Visited;
+  bool FoundLoad = false;
+  SmallVector<SDValue, 4> ChainOps;
+  SmallVector<const SDNode *, 4> LoopWorklist;
+  SmallPtrSet<const SDNode *, 16> Visited;
     for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i) {
       SDValue Op = Chain.getOperand(i);
       if (Op == Load.getValue(1)) {
@@ -2144,9 +2144,6 @@ static bool isFusableLoadOpStorePattern(
       if (SDNode::hasPredecessorHelper(Load.getNode(), Visited, LoopWorklist,
                                        Max, true))
         return false;
-      // Fail conservatively if we ended loop search early.
-      if (Visited.size() >= Max)
-        return false;
     }
 
     // Make a new TokenFactor with all the other input chains except