vendor/llvm-project/llvmorg-10.0.0-rc2-70-ge5cb70267e7

1 files changed, 6 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopRotation.cpp b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
index 0868e742f4ee..67c20b2edae8 100644
--- a/llvm/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
@@ -81,10 +81,8 @@ public:
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequired<AssumptionCacheTracker>();
     AU.addRequired<TargetTransformInfoWrapperPass>();
-    if (EnableMSSALoopDependency) {
-      AU.addRequired<MemorySSAWrapperPass>();
+    if (EnableMSSALoopDependency)
       AU.addPreserved<MemorySSAWrapperPass>();
-    }
     getLoopAnalysisUsage(AU);
   }
 
@@ -101,8 +99,11 @@ public:
     const SimplifyQuery SQ = getBestSimplifyQuery(*this, F);
     Optional<MemorySSAUpdater> MSSAU;
     if (EnableMSSALoopDependency) {
-      MemorySSA *MSSA = &getAnalysis<MemorySSAWrapperPass>().getMSSA();
-      MSSAU = MemorySSAUpdater(MSSA);
+      // Not requiring MemorySSA and getting it only if available will split
+      // the loop pass pipeline when LoopRotate is being run first.
+      auto *MSSAA = getAnalysisIfAvailable<MemorySSAWrapperPass>();
+      if (MSSAA)
+        MSSAU = MemorySSAUpdater(&MSSAA->getMSSA());
     }
     return LoopRotation(L, LI, TTI, AC, &DT, &SE,
                         MSSAU.hasValue() ? MSSAU.getPointer() : nullptr, SQ,