1 files changed, 39 insertions, 1 deletions
diff --git a/contrib/llvm/lib/Transforms/Scalar/LoopSink.cpp b/contrib/llvm/lib/Transforms/Scalar/LoopSink.cpp
index f3f4152..c9d55b4 100644
--- a/contrib/llvm/lib/Transforms/Scalar/LoopSink.cpp
+++ b/contrib/llvm/lib/Transforms/Scalar/LoopSink.cpp
@@ -1,4 +1,4 @@
-//===-- LoopSink.cpp - Loop Sink Pass ------------------------===//
+//===-- LoopSink.cpp - Loop Sink Pass -------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -28,8 +28,10 @@
 //       InsertBBs = UseBBs - DomBBs + BB
 //   For BB in InsertBBs:
 //     Insert I at BB's beginning
+//
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Transforms/Scalar/LoopSink.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/AliasSetTracker.h"
@@ -297,6 +299,42 @@ static bool sinkLoopInvariantInstructions(Loop &L, AAResults &AA, LoopInfo &LI,
   return Changed;
 }
 
+PreservedAnalyses LoopSinkPass::run(Function &F, FunctionAnalysisManager &FAM) {
+  LoopInfo &LI = FAM.getResult<LoopAnalysis>(F);
+  // Nothing to do if there are no loops.
+  if (LI.empty())
+    return PreservedAnalyses::all();
+
+  AAResults &AA = FAM.getResult<AAManager>(F);
+  DominatorTree &DT = FAM.getResult<DominatorTreeAnalysis>(F);
+  BlockFrequencyInfo &BFI = FAM.getResult<BlockFrequencyAnalysis>(F);
+
+  // We want to do a postorder walk over the loops. Since loops are a tree this
+  // is equivalent to a reversed preorder walk and preorder is easy to compute
+  // without recursion. Since we reverse the preorder, we will visit siblings
+  // in reverse program order. This isn't expected to matter at all but is more
+  // consistent with sinking algorithms which generally work bottom-up.
+  SmallVector<Loop *, 4> PreorderLoops = LI.getLoopsInPreorder();
+
+  bool Changed = false;
+  do {
+    Loop &L = *PreorderLoops.pop_back_val();
+
+    // Note that we don't pass SCEV here because it is only used to invalidate
+    // loops in SCEV and we don't preserve (or request) SCEV at all making that
+    // unnecessary.
+    Changed |= sinkLoopInvariantInstructions(L, AA, LI, DT, BFI,
+                                             /*ScalarEvolution*/ nullptr);
+  } while (!PreorderLoops.empty());
+
+  if (!Changed)
+    return PreservedAnalyses::all();
+
+  PreservedAnalyses PA;
+  PA.preserveSet<CFGAnalyses>();
+  return PA;
+}
+
 namespace {
 struct LegacyLoopSinkPass : public LoopPass {
   static char ID;