[PM] Sink the specific analyses preserved by SplitBlock into its

interface, removing Pass from its interface.

This also makes those analyses optional so that passes which don't even
preserve these (or use them) can skip the logic entirely.

llvm-svn: 226394

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index c7ea283d..dff756e 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -28,6 +28,7 @@
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Analysis/ScalarEvolutionExpander.h"
 #include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Dominators.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
@@ -316,13 +317,17 @@ bool llvm::UnrollRuntimeLoopProlog(Loop *L, unsigned Count, LoopInfo *LI,
   if (Loop *ParentLoop = L->getParentLoop())
     SE->forgetLoop(ParentLoop);
 
+  // Grab the dominator tree so we can preserve it.
+  auto *DTWP = LPM->getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+  auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
+
   BasicBlock *PH = L->getLoopPreheader();
   BasicBlock *Header = L->getHeader();
   BasicBlock *Latch = L->getLoopLatch();
   // It helps to splits the original preheader twice, one for the end of the
   // prolog code and one for a new loop preheader
   BasicBlock *PEnd = SplitEdge(PH, Header, LPM->getAsPass());
-  BasicBlock *NewPH = SplitBlock(PEnd, PEnd->getTerminator(), LPM->getAsPass());
+  BasicBlock *NewPH = SplitBlock(PEnd, PEnd->getTerminator(), DT, LI);
   BranchInst *PreHeaderBR = cast<BranchInst>(PH->getTerminator());
 
   // Compute the number of extra iterations required, which is: