[PM] Remove the Pass argument from all of the critical edge splitting
APIs and replace it and numerous booleans with an option struct.

The critical edge splitting API has a really large surface of flags and
so it seems worth burning a small option struct / builder. This struct
can be constructed with the various preserved analyses and then flags
can be flipped in a builder style.

The various users are now responsible for directly passing along their
analysis information. This should be enough for the critical edge
splitting to work cleanly with the new pass manager as well.

This API is still pretty crufty and could be cleaned up a lot, but I've
focused on this change just threading an option struct rather than
a pass through the API.

llvm-svn: 226456
diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index c2304d7..866fb83 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -234,15 +234,20 @@
 BasicBlock *llvm::SplitEdge(BasicBlock *BB, BasicBlock *Succ, Pass *P) {
   unsigned SuccNum = GetSuccessorNumber(BB, Succ);
 
-  // If this is a critical edge, let SplitCriticalEdge do it.
-  TerminatorInst *LatchTerm = BB->getTerminator();
-  if (SplitCriticalEdge(LatchTerm, SuccNum, P))
-    return LatchTerm->getSuccessor(SuccNum);
-
+  auto *AA = P->getAnalysisIfAvailable<AliasAnalysis>();
   auto *DTWP = P->getAnalysisIfAvailable<DominatorTreeWrapperPass>();
   auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
   auto *LIWP = P->getAnalysisIfAvailable<LoopInfoWrapperPass>();
   auto *LI = LIWP ? &LIWP->getLoopInfo() : nullptr;
+  bool PreserveLCSSA = P->mustPreserveAnalysisID(LCSSAID);
+  auto Options = CriticalEdgeSplittingOptions(AA, DT, LI);
+  if (PreserveLCSSA)
+    Options.setPreserveLCSSA();
+
+  // If this is a critical edge, let SplitCriticalEdge do it.
+  TerminatorInst *LatchTerm = BB->getTerminator();
+  if (SplitCriticalEdge(LatchTerm, SuccNum, Options))
+    return LatchTerm->getSuccessor(SuccNum);
 
   // If the edge isn't critical, then BB has a single successor or Succ has a
   // single pred.  Split the block.
@@ -261,13 +266,15 @@
   return SplitBlock(BB, BB->getTerminator(), DT, LI);
 }
 
-unsigned llvm::SplitAllCriticalEdges(Function &F, Pass *P) {
+unsigned
+llvm::SplitAllCriticalEdges(Function &F,
+                            const CriticalEdgeSplittingOptions &Options) {
   unsigned NumBroken = 0;
   for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
     TerminatorInst *TI = I->getTerminator();
     if (TI->getNumSuccessors() > 1 && !isa<IndirectBrInst>(TI))
       for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
-        if (SplitCriticalEdge(TI, i, P))
+        if (SplitCriticalEdge(TI, i, Options))
           ++NumBroken;
   }
   return NumBroken;
diff --git a/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp b/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
index 9324119..7e83c9e 100644
--- a/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
+++ b/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
@@ -42,7 +42,12 @@
     }
 
     bool runOnFunction(Function &F) override {
-      unsigned N = SplitAllCriticalEdges(F, this);
+      auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+      auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
+      auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>();
+      auto *LI = LIWP ? &LIWP->getLoopInfo() : nullptr;
+      unsigned N =
+          SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions(DT, LI));
       NumBroken += N;
       return N > 0;
     }
@@ -126,10 +131,9 @@
 /// to.
 ///
 BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum,
-                                    Pass *P, bool MergeIdenticalEdges,
-                                    bool DontDeleteUselessPhis,
-                                    bool SplitLandingPads) {
-  if (!isCriticalEdge(TI, SuccNum, MergeIdenticalEdges)) return nullptr;
+                                    const CriticalEdgeSplittingOptions &Options) {
+  if (!isCriticalEdge(TI, SuccNum, Options.MergeIdenticalEdges))
+    return nullptr;
 
   assert(!isa<IndirectBrInst>(TI) &&
          "Cannot split critical edge from IndirectBrInst");
@@ -180,33 +184,22 @@
   // If there are any other edges from TIBB to DestBB, update those to go
   // through the split block, making those edges non-critical as well (and
   // reducing the number of phi entries in the DestBB if relevant).
-  if (MergeIdenticalEdges) {
+  if (Options.MergeIdenticalEdges) {
     for (unsigned i = SuccNum+1, e = TI->getNumSuccessors(); i != e; ++i) {
       if (TI->getSuccessor(i) != DestBB) continue;
 
       // Remove an entry for TIBB from DestBB phi nodes.
-      DestBB->removePredecessor(TIBB, DontDeleteUselessPhis);
+      DestBB->removePredecessor(TIBB, Options.DontDeleteUselessPHIs);
 
       // We found another edge to DestBB, go to NewBB instead.
       TI->setSuccessor(i, NewBB);
     }
   }
 
-
-
-  // If we don't have a pass object, we can't update anything...
-  if (!P) return NewBB;
-
-
-  auto *AA = P->getAnalysisIfAvailable<AliasAnalysis>();
-  DominatorTreeWrapperPass *DTWP =
-      P->getAnalysisIfAvailable<DominatorTreeWrapperPass>();
-  DominatorTree *DT = DTWP ? &DTWP->getDomTree() : nullptr;
-  auto *LIWP = P->getAnalysisIfAvailable<LoopInfoWrapperPass>();
-  LoopInfo *LI = LIWP ? &LIWP->getLoopInfo() : nullptr;
-  bool PreserveLCSSA = P->mustPreserveAnalysisID(LCSSAID);
-
   // If we have nothing to update, just return.
+  auto *AA = Options.AA;
+  auto *DT = Options.DT;
+  auto *LI = Options.LI;
   if (!DT && !LI)
     return NewBB;
 
@@ -299,7 +292,7 @@
                "Split point for loop exit is contained in loop!");
 
         // Update LCSSA form in the newly created exit block.
-        if (PreserveLCSSA) {
+        if (Options.PreserveLCSSA) {
           createPHIsForSplitLoopExit(TIBB, NewBB, DestBB);
         }
 
@@ -329,8 +322,8 @@
           assert(!DestBB->isLandingPad() &&
                  "We don't split edges to landing pads!");
           BasicBlock *NewExitBB = SplitBlockPredecessors(
-              DestBB, LoopPreds, "split", AA, DT, LI, PreserveLCSSA);
-          if (PreserveLCSSA)
+              DestBB, LoopPreds, "split", AA, DT, LI, Options.PreserveLCSSA);
+          if (Options.PreserveLCSSA)
             createPHIsForSplitLoopExit(LoopPreds, NewExitBB, DestBB);
         }
       }