EdgeThreadingCloner. Remove splitCriticalEdges calls.

Author: atrick

include/swift/SILOptimizer/Utils/BasicBlockOptUtils.h

@@ -136,9 +136,9 @@ class SinkAddressProjections {
 /// block's branch to jump to the newly cloned block, call cloneBranchTarget
 /// instead.
 ///
-/// After cloning, call splitCriticalEdges, then updateSSAAfterCloning. This is
-/// decoupled from cloning becaused some clients perform CFG edges updates after
-/// cloning but before splitting CFG edges.
+/// After cloning, call updateSSAAfterCloning. This is decoupled from cloning
+/// becaused some clients perform CFG edges updates after cloning but before
+/// splitting CFG edges.
 class BasicBlockCloner : public SILCloner<BasicBlockCloner> {
   using SuperTy = SILCloner<BasicBlockCloner>;
   friend class SILCloner<BasicBlockCloner>;
@@ -225,12 +225,7 @@ class BasicBlockCloner : public SILCloner<BasicBlockCloner> {
 
   bool wasCloned() { return isBlockCloned(origBB); }
 
-  /// Call this after processing all instructions to fix the control flow
-  /// graph. The branch cloner may have left critical edges.
-  bool splitCriticalEdges(DominanceInfo *domInfo, SILLoopInfo *loopInfo);
-
-  /// Helper function to perform SSA updates after calling both
-  /// cloneBranchTarget and splitCriticalEdges.
+  /// Helper function to perform SSA updates after calling cloneBranchTarget.
   void updateSSAAfterCloning();
 
 protected:

lib/SILOptimizer/Transforms/SimplifyCFG.cpp

@@ -1109,8 +1109,6 @@ bool SimplifyCFG::tryJumpThreading(BranchInst *BI) {
   // Duplicate the destination block into this one, rewriting uses of the BBArgs
   // to use the branch arguments as we go.
   Cloner.cloneBranchTarget(BI);
-  // Does not currently update DominanceInfo.
-  Cloner.splitCriticalEdges(nullptr, nullptr);
   Cloner.updateSSAAfterCloning();
 
   // Once all the instructions are copied, we can nuke BI itself.  We also add

lib/SILOptimizer/Utils/BasicBlockOptUtils.cpp

@@ -134,28 +134,6 @@ void BasicBlockCloner::updateSSAAfterCloning() {
   }
 }
 
-// FIXME: Remove this. SILCloner should not create critical edges.
-bool BasicBlockCloner::splitCriticalEdges(DominanceInfo *domInfo,
-                                          SILLoopInfo *loopInfo) {
-  bool changed = false;
-  // Remove any critical edges that the EdgeThreadingCloner may have
-  // accidentally created.
-  for (unsigned succIdx = 0, succEnd = origBB->getSuccessors().size();
-       succIdx != succEnd; ++succIdx) {
-    if (nullptr
-        != splitCriticalEdge(origBB->getTerminator(), succIdx, domInfo,
-                             loopInfo))
-      changed |= true;
-  }
-  for (unsigned succIdx = 0, succEnd = getNewBB()->getSuccessors().size();
-       succIdx != succEnd; ++succIdx) {
-    auto *newBB = splitCriticalEdge(getNewBB()->getTerminator(), succIdx,
-                                    domInfo, loopInfo);
-    changed |= (newBB != nullptr);
-  }
-  return changed;
-}
-
 void BasicBlockCloner::sinkAddressProjections() {
   // Because the address projections chains will be disjoint (an instruction
   // in one chain cannot use the result of an instruction in another chain),