[VPlan] Remove unused IsReplicator arg from createVPRegionBlock (NFC).

The argument is always true, remove it.

Author: fhahn

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -4188,13 +4188,11 @@ class VPlan {
     return VPB;
   }
 
-  /// Create a new VPRegionBlock with \p Name and entry and exiting blocks set
-  /// to nullptr. If \p IsReplicator is true, the region is a replicate region.
-  /// The returned block is owned by the VPlan and deleted once the VPlan is
-  /// destroyed.
-  VPRegionBlock *createVPRegionBlock(const std::string &Name = "",
-                                     bool IsReplicator = false) {
-    auto *VPB = new VPRegionBlock(Name, IsReplicator);
+  /// Create a new loop VPRegionBlock with \p Name and entry and exiting blocks set
+  /// to nullptr. The returned block is owned by the VPlan and deleted once the
+  /// VPlan is destroyed.
+  VPRegionBlock *createVPRegionBlock(const std::string &Name = "") {
+    auto *VPB = new VPRegionBlock(Name);
     CreatedBlocks.push_back(VPB);
     return VPB;
   }

llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp

@@ -411,7 +411,7 @@ static void createLoopRegion(VPlan &Plan, VPBlockBase *HeaderVPB) {
   // LatchExitVPB, taking care to preserve the original predecessor & successor
   // order of blocks. Set region entry and exiting after both HeaderVPB and
   // LatchVPBB have been disconnected from their predecessors/successors.
-  auto *R = Plan.createVPRegionBlock("", false /*isReplicator*/);
+  auto *R = Plan.createVPRegionBlock();
   VPBlockUtils::insertOnEdge(LatchVPBB, LatchExitVPB, R);
   VPBlockUtils::disconnectBlocks(LatchVPBB, R);
   VPBlockUtils::connectBlocks(PreheaderVPBB, R);