1 files changed, 17 insertions, 18 deletions
diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index ea867127c56..7cd69d2b847 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -748,26 +748,25 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount, bool Force,
       // OuterL includes all loops for which we can break loop-simplify, so
       // it's sufficient to simplify only it (it'll recursively simplify inner
       // loops too).
-      // TODO: That potentially might be compile-time expensive. We should try
-      // to fix the loop-simplified form incrementally.
-      // Note that we only preserve LCSSA at this stage if we need to and if we
-      // won't end up fixing it. If we end up fixing it anyways, we don't need
-      // to preserve it here and in fact we can't because it isn't correct.
-      simplifyLoop(OuterL, DT, LI, SE, AC, PreserveLCSSA && !NeedToFixLCSSA);
-
-      // 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
-      // LoopInfo's been updated by markAsRemoved.
-      Loop *LatchLoop = LI->getLoopFor(Latches.back());
-      if (!OuterL->contains(LatchLoop))
-        while (OuterL->getParentLoop() != LatchLoop)
-          OuterL = OuterL->getParentLoop();
-
-      if (NeedToFixLCSSA)
-        formLCSSARecursively(*OuterL, *DT, LI, SE);
-      else if (PreserveLCSSA)
+      if (NeedToFixLCSSA) {
+        // 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 LoopInfo's been updated by markAsRemoved.
+        Loop *LatchLoop = LI->getLoopFor(Latches.back());
+        Loop *FixLCSSALoop = OuterL;
+        if (!FixLCSSALoop->contains(LatchLoop))
+          while (FixLCSSALoop->getParentLoop() != LatchLoop)
+            FixLCSSALoop = FixLCSSALoop->getParentLoop();
+
+        formLCSSARecursively(*FixLCSSALoop, *DT, LI, SE);
+      } else if (PreserveLCSSA) {
         assert(OuterL->isLCSSAForm(*DT) &&
                "Loops should be in LCSSA form after loop-unroll.");
+      }
+
+      // TODO: That potentially might be compile-time expensive. We should try
+      // to fix the loop-simplified form incrementally.
+      simplifyLoop(OuterL, DT, LI, SE, AC, PreserveLCSSA);
     } else {
       // Simplify loops for which we might've broken loop-simplify form.
       for (Loop *SubLoop : LoopsToSimplify)