[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

5 files changed, 26 insertions, 19 deletions

diff --git a/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h b/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
index fab7580860a..eb0edb75fd5 100644
--- a/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
+++ b/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
@@ -153,7 +153,8 @@ BasicBlock *SplitEdge(BasicBlock *From, BasicBlock *To, Pass *P);
 /// to a new block.  The two blocks are joined by an unconditional branch and
 /// the loop info is updated.
 ///
-BasicBlock *SplitBlock(BasicBlock *Old, Instruction *SplitPt, Pass *P);
+BasicBlock *SplitBlock(BasicBlock *Old, Instruction *SplitPt,
+                       DominatorTree *DT = nullptr, LoopInfo *LI = nullptr);
 
 /// SplitBlockPredecessors - This method transforms BB by introducing a new
 /// basic block into the function, and moving some of the predecessors of BB to
diff --git a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
index eb684d4c037..0ff6e015c80 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -737,7 +737,7 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond,
   // without actually branching to it (the exit block should be dominated by the
   // loop header, not the preheader).
   assert(!L->contains(ExitBlock) && "Exit block is in the loop?");
-  BasicBlock *NewExit = SplitBlock(ExitBlock, ExitBlock->begin(), this);
+  BasicBlock *NewExit = SplitBlock(ExitBlock, ExitBlock->begin(), DT, LI);
 
   // Okay, now we have a position to branch from and a position to branch to,
   // insert the new conditional branch.
diff --git a/llvm/lib/Transforms/Scalar/PartiallyInlineLibCalls.cpp b/llvm/lib/Transforms/Scalar/PartiallyInlineLibCalls.cpp
index 0ca715337e0..d6adfbea5d4 100644
--- a/llvm/lib/Transforms/Scalar/PartiallyInlineLibCalls.cpp
+++ b/llvm/lib/Transforms/Scalar/PartiallyInlineLibCalls.cpp
@@ -127,7 +127,7 @@ bool PartiallyInlineLibCalls::optimizeSQRT(CallInst *Call,
 
   // Move all instructions following Call to newly created block JoinBB.
   // Create phi and replace all uses.
-  BasicBlock *JoinBB = llvm::SplitBlock(&CurrBB, Call->getNextNode(), this);
+  BasicBlock *JoinBB = llvm::SplitBlock(&CurrBB, Call->getNextNode());
   IRBuilder<> Builder(JoinBB, JoinBB->begin());
   PHINode *Phi = Builder.CreatePHI(Call->getType(), 2);
   Call->replaceAllUsesWith(Phi);
diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index f450906b7e7..2fb54610025 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -239,6 +239,11 @@ BasicBlock *llvm::SplitEdge(BasicBlock *BB, BasicBlock *Succ, Pass *P) {
   if (SplitCriticalEdge(LatchTerm, SuccNum, P))
     return LatchTerm->getSuccessor(SuccNum);
 
+  auto *DTWP = P->getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+  auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
+  auto *LIWP = P->getAnalysisIfAvailable<LoopInfoWrapperPass>();
+  auto *LI = LIWP ? &LIWP->getLoopInfo() : nullptr;
+
   // If the edge isn't critical, then BB has a single successor or Succ has a
   // single pred.  Split the block.
   if (BasicBlock *SP = Succ->getSinglePredecessor()) {
@@ -246,14 +251,14 @@ BasicBlock *llvm::SplitEdge(BasicBlock *BB, BasicBlock *Succ, Pass *P) {
     // block.
     assert(SP == BB && "CFG broken");
     SP = nullptr;
-    return SplitBlock(Succ, Succ->begin(), P);
+    return SplitBlock(Succ, Succ->begin(), DT, LI);
   }
 
   // Otherwise, if BB has a single successor, split it at the bottom of the
   // block.
   assert(BB->getTerminator()->getNumSuccessors() == 1 &&
          "Should have a single succ!");
-  return SplitBlock(BB, BB->getTerminator(), P);
+  return SplitBlock(BB, BB->getTerminator(), DT, LI);
 }
 
 unsigned llvm::SplitAllCriticalEdges(Function &F, Pass *P) {
@@ -273,7 +278,8 @@ unsigned llvm::SplitAllCriticalEdges(Function &F, Pass *P) {
 /// to a new block.  The two blocks are joined by an unconditional branch and
 /// the loop info is updated.
 ///
-BasicBlock *llvm::SplitBlock(BasicBlock *Old, Instruction *SplitPt, Pass *P) {
+BasicBlock *llvm::SplitBlock(BasicBlock *Old, Instruction *SplitPt,
+                             DominatorTree *DT, LoopInfo *LI) {
   BasicBlock::iterator SplitIt = SplitPt;
   while (isa<PHINode>(SplitIt) || isa<LandingPadInst>(SplitIt))
     ++SplitIt;
@@ -281,28 +287,23 @@ BasicBlock *llvm::SplitBlock(BasicBlock *Old, Instruction *SplitPt, Pass *P) {
 
   // The new block lives in whichever loop the old one did. This preserves
   // LCSSA as well, because we force the split point to be after any PHI nodes.
-  if (auto *LIWP = P->getAnalysisIfAvailable<LoopInfoWrapperPass>()) {
-    LoopInfo &LI = LIWP->getLoopInfo();
-    if (Loop *L = LI.getLoopFor(Old))
-      L->addBasicBlockToLoop(New, LI);
-  }
+  if (LI)
+    if (Loop *L = LI->getLoopFor(Old))
+      L->addBasicBlockToLoop(New, *LI);
 
-  if (DominatorTreeWrapperPass *DTWP =
-          P->getAnalysisIfAvailable<DominatorTreeWrapperPass>()) {
-    DominatorTree &DT = DTWP->getDomTree();
+  if (DT)
     // Old dominates New. New node dominates all other nodes dominated by Old.
-    if (DomTreeNode *OldNode = DT.getNode(Old)) {
+    if (DomTreeNode *OldNode = DT->getNode(Old)) {
       std::vector<DomTreeNode *> Children;
       for (DomTreeNode::iterator I = OldNode->begin(), E = OldNode->end();
            I != E; ++I)
         Children.push_back(*I);
 
-      DomTreeNode *NewNode = DT.addNewBlock(New, Old);
+      DomTreeNode *NewNode = DT->addNewBlock(New, Old);
       for (std::vector<DomTreeNode *>::iterator I = Children.begin(),
              E = Children.end(); I != E; ++I)
-        DT.changeImmediateDominator(*I, NewNode);
+        DT->changeImmediateDominator(*I, NewNode);
     }
-  }
 
   return New;
 }
diff --git a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index c7ea283da79..dff756ed127 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: