Refactor collectChildrenInLoop to LoopUtils [NFC]

Summary: Move to LoopUtils method that collects all children of a node inside a loop.

Reviewers: majnemer, sanjoy

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D37870

llvm-svn: 313322

include/llvm/Transforms/Utils/LoopUtils.h

@@ -455,6 +455,11 @@ bool promoteLoopAccessesToScalars(const SmallSetVector<Value *, 8> &,
                                   Loop *, AliasSetTracker *, LoopSafetyInfo *,
                                   OptimizationRemarkEmitter *);
 
+/// Does a BFS from a given node to all of its children inside a given loop.
+/// The returned vector of nodes includes the starting point.
+SmallVector<DomTreeNode *, 16> collectChildrenInLoop(DomTreeNode *N,
+                                                     const Loop *CurLoop);
+
 /// \brief Computes safety information for a loop
 /// checks loop body & header for the possibility of may throw
 /// exception, it takes LoopSafetyInfo and loop as argument.

lib/Transforms/Scalar/LICM.cpp

@@ -345,29 +345,6 @@ bool LoopInvariantCodeMotion::runOnLoop(Loop *L, AliasAnalysis *AA,
   return Changed;
 }
 
-// Does a BFS from a given node to all of its children inside a given loop.
-// The returned vector of nodes includes the starting point.
-static SmallVector<DomTreeNode *, 16>
-collectChildrenInLoop(DomTreeNode *N, const Loop *CurLoop) {
-  SmallVector<DomTreeNode *, 16> Worklist;
-  auto add_region_to_worklist = [&](DomTreeNode *DTN) {
-    // Only include subregions in the top level loop.
-    BasicBlock *BB = DTN->getBlock();
-    if (CurLoop->contains(BB))
-      Worklist.push_back(DTN);
-  };
-
-  add_region_to_worklist(N);
-
-  for (size_t I = 0; I < Worklist.size(); I++) {
-    DomTreeNode *DTN = Worklist[I];
-    for (DomTreeNode *Child : DTN->getChildren())
-      add_region_to_worklist(Child);
-  }
-
-  return Worklist;
-}
-
 /// Walk the specified region of the CFG (defined by all blocks dominated by
 /// the specified block, and that are in the current loop) in reverse depth
 /// first order w.r.t the DominatorTree.  This allows us to visit uses before

lib/Transforms/Utils/LoopUtils.cpp

@@ -1116,6 +1116,27 @@ Optional<const MDOperand *> llvm::findStringMetadataForLoop(Loop *TheLoop,
   return None;
 }
 
+/// Does a BFS from a given node to all of its children inside a given loop.
+/// The returned vector of nodes includes the starting point.
+SmallVector<DomTreeNode *, 16>
+llvm::collectChildrenInLoop(DomTreeNode *N, const Loop *CurLoop) {
+  SmallVector<DomTreeNode *, 16> Worklist;
+  auto AddRegionToWorklist = [&](DomTreeNode *DTN) {
+    // Only include subregions in the top level loop.
+    BasicBlock *BB = DTN->getBlock();
+    if (CurLoop->contains(BB))
+      Worklist.push_back(DTN);
+  };
+
+  AddRegionToWorklist(N);
+
+  for (size_t I = 0; I < Worklist.size(); I++)
+    for (DomTreeNode *Child : Worklist[I]->getChildren())
+      AddRegionToWorklist(Child);
+
+  return Worklist;
+}
+
 /// Returns true if the instruction in a loop is guaranteed to execute at least
 /// once.
 bool llvm::isGuaranteedToExecute(const Instruction &Inst,