Revert "[LoopSimplify] Factor the logic to form dedicated exits into a utility."

This leads to a segfault. Chandler already has a test case and should be
able to recommit with a fix soon.

llvm-svn: 306252

1 files changed, 0 insertions, 62 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index 88fa981..e545bc0 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -29,7 +29,6 @@
 #include "llvm/IR/ValueHandle.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
 
 using namespace llvm;
 using namespace llvm::PatternMatch;
@@ -923,67 +922,6 @@ bool InductionDescriptor::isInductionPHI(PHINode *Phi, const Loop *TheLoop,
   return true;
 }
 
-bool llvm::formDedicatedExitBlocks(Loop *L, DominatorTree *DT, LoopInfo *LI,
-                                   bool PreserveLCSSA) {
-  bool Changed = false;
-
-  // We re-use a vector for the in-loop predecesosrs.
-  SmallVector<BasicBlock *, 4> InLoopPredecessors;
-
-  auto RewriteExit = [&](BasicBlock *BB) {
-    // See if there are any non-loop predecessors of this exit block and
-    // keep track of the in-loop predecessors.
-    bool IsDedicatedExit = true;
-    for (auto *PredBB : predecessors(BB))
-      if (L->contains(PredBB)) {
-        if (isa<IndirectBrInst>(PredBB->getTerminator()))
-          // We cannot rewrite exiting edges from an indirectbr.
-          return false;
-
-        InLoopPredecessors.push_back(PredBB);
-      } else {
-        IsDedicatedExit = false;
-      }
-
-    // Nothing to do if this is already a dedicated exit.
-    if (IsDedicatedExit) {
-      InLoopPredecessors.clear();
-      return false;
-    }
-
-    assert(!InLoopPredecessors.empty() && "Must have *some* loop predecessor!");
-    auto *NewExitBB = SplitBlockPredecessors(
-        BB, InLoopPredecessors, ".loopexit", DT, LI, PreserveLCSSA);
-
-    if (!NewExitBB)
-      DEBUG(dbgs() << "WARNING: Can't create a dedicated exit block for loop: "
-                   << *L << "\n");
-    else
-      DEBUG(dbgs() << "LoopSimplify: Creating dedicated exit block "
-                   << NewExitBB->getName() << "\n");
-    InLoopPredecessors.clear();
-    return true;
-  };
-
-  // Walk the exit blocks directly rather than building up a data structure for
-  // them, but only visit each one once.
-  SmallPtrSet<BasicBlock *, 4> Visited;
-  for (auto *BB : L->blocks())
-    for (auto *SuccBB : successors(BB)) {
-      // We're looking for exit blocks so skip in-loop successors.
-      if (L->contains(SuccBB))
-        continue;
-
-      // Visit each exit block exactly once.
-      if (!Visited.insert(SuccBB).second)
-        continue;
-
-      Changed |= RewriteExit(SuccBB);
-    }
-
-  return Changed;
-}
-
 /// \brief Returns the instructions that use values defined in the loop.
 SmallVector<Instruction *, 8> llvm::findDefsUsedOutsideOfLoop(Loop *L) {
   SmallVector<Instruction *, 8> UsedOutside;