1 files changed, 22 insertions, 6 deletions

diff --git a/lib/Transforms/Utils/LoopUnroll.cpp b/lib/Transforms/Utils/LoopUnroll.cpp
index d953e30..c86b82c 100644
--- a/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/lib/Transforms/Utils/LoopUnroll.cpp
@@ -23,6 +23,7 @@
 #include "llvm/Analysis/LoopPass.h"
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/LLVMContext.h"
@@ -242,21 +243,25 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
                            Twine("completely unrolled loop with ") +
                                Twine(TripCount) + " iterations");
   } else {
+    auto EmitDiag = [&](const Twine &T) {
+      emitOptimizationRemark(Ctx, DEBUG_TYPE, *F, LoopLoc,
+                             "unrolled loop by a factor of " + Twine(Count) +
+                                 T);
+    };
+
     DEBUG(dbgs() << "UNROLLING loop %" << Header->getName()
           << " by " << Count);
-    Twine DiagMsg("unrolled loop by a factor of " + Twine(Count));
     if (TripMultiple == 0 || BreakoutTrip != TripMultiple) {
       DEBUG(dbgs() << " with a breakout at trip " << BreakoutTrip);
-      DiagMsg.concat(" with a breakout at trip " + Twine(BreakoutTrip));
+      EmitDiag(" with a breakout at trip " + Twine(BreakoutTrip));
     } else if (TripMultiple != 1) {
       DEBUG(dbgs() << " with " << TripMultiple << " trips per branch");
-      DiagMsg.concat(" with " + Twine(TripMultiple) + " trips per branch");
+      EmitDiag(" with " + Twine(TripMultiple) + " trips per branch");
     } else if (RuntimeTripCount) {
       DEBUG(dbgs() << " with run-time trip count");
-      DiagMsg.concat(" with run-time trip count");
+      EmitDiag(" with run-time trip count");
     }
     DEBUG(dbgs() << "!\n");
-    emitOptimizationRemark(Ctx, DEBUG_TYPE, *F, LoopLoc, DiagMsg);
   }
 
   bool ContinueOnTrue = L->contains(BI->getSuccessor(0));
@@ -485,8 +490,19 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
     if (!OuterL && !CompletelyUnroll)
       OuterL = L;
     if (OuterL) {
+      DataLayoutPass *DLP = PP->getAnalysisIfAvailable<DataLayoutPass>();
+      const DataLayout *DL = DLP ? &DLP->getDataLayout() : nullptr;
       ScalarEvolution *SE = PP->getAnalysisIfAvailable<ScalarEvolution>();
-      simplifyLoop(OuterL, DT, LI, PP, /*AliasAnalysis*/ nullptr, SE);
+      simplifyLoop(OuterL, DT, LI, PP, /*AliasAnalysis*/ nullptr, SE, DL);
+
+      // LCSSA must be performed on the outermost affected loop. The unrolled
+      // loop's last loop latch is guaranteed to be in the outermost loop after
+      // deleteLoopFromQueue updates LoopInfo.
+      Loop *LatchLoop = LI->getLoopFor(Latches.back());
+      if (!OuterL->contains(LatchLoop))
+        while (OuterL->getParentLoop() != LatchLoop)
+          OuterL = OuterL->getParentLoop();
+
       formLCSSARecursively(*OuterL, *DT, SE);
     }
   }