1 files changed, 23 insertions, 8 deletions
diff --git a/gnu/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/gnu/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index 861a50cf354..85da3ba899a 100644
--- a/gnu/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/gnu/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -112,6 +112,18 @@ static void ConnectProlog(Loop *L, Value *BECount, unsigned Count,
     }
   }
 
+  // Make sure that created prolog loop is in simplified form
+  SmallVector<BasicBlock *, 4> PrologExitPreds;
+  Loop *PrologLoop = LI->getLoopFor(PrologLatch);
+  if (PrologLoop) {
+    for (BasicBlock *PredBB : predecessors(PrologExit))
+      if (PrologLoop->contains(PredBB))
+        PrologExitPreds.push_back(PredBB);
+
+    SplitBlockPredecessors(PrologExit, PrologExitPreds, ".unr-lcssa", DT, LI,
+                           PreserveLCSSA);
+  }
+
   // Create a branch around the original loop, which is taken if there are no
   // iterations remaining to be executed after running the prologue.
   Instruction *InsertPt = PrologExit->getTerminator();
@@ -289,15 +301,17 @@ static void CloneLoopBlocks(Loop *L, Value *NewIter,
       LI->addTopLevelLoop(NewLoop);
   }
 
+  NewLoopsMap NewLoops;
+  NewLoops[L] = NewLoop;
   // For each block in the original loop, create a new copy,
   // and update the value map with the newly created values.
   for (LoopBlocksDFS::RPOIterator BB = BlockBegin; BB != BlockEnd; ++BB) {
     BasicBlock *NewBB = CloneBasicBlock(*BB, VMap, "." + suffix, F);
     NewBlocks.push_back(NewBB);
 
-    if (NewLoop)
-      NewLoop->addBasicBlockToLoop(NewBB, *LI);
-    else if (ParentLoop)
+    if (NewLoop) {
+      addClonedBlockToLoopInfo(*BB, NewBB, LI, NewLoops);
+    } else if (ParentLoop)
       ParentLoop->addBasicBlockToLoop(NewBB, *LI);
 
     VMap[*BB] = NewBB;
@@ -479,11 +493,6 @@ bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
   if (Log2_32(Count) > BEWidth)
     return false;
 
-  // If this loop is nested, then the loop unroller changes the code in the
-  // parent loop, so the Scalar Evolution pass needs to be run again.
-  if (Loop *ParentLoop = L->getParentLoop())
-    SE->forgetLoop(ParentLoop);
-
   BasicBlock *Latch = L->getLoopLatch();
 
   // Loop structure is the following:
@@ -673,6 +682,12 @@ bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
     ConnectProlog(L, BECount, Count, PrologExit, PreHeader, NewPreHeader,
                   VMap, DT, LI, PreserveLCSSA);
   }
+
+  // If this loop is nested, then the loop unroller changes the code in the
+  // parent loop, so the Scalar Evolution pass needs to be run again.
+  if (Loop *ParentLoop = L->getParentLoop())
+    SE->forgetLoop(ParentLoop);
+
   NumRuntimeUnrolled++;
   return true;
 }