[llvm] [VPlan] Connect (MemRuntime|SCEV)Check blocks as VPlan transform (NFC). (PR #143879)

[via llvm-commits]

================
@@ -2025,57 +2005,30 @@ class GeneratedRTChecks {
   /// Adds the generated SCEVCheckBlock before \p LoopVectorPreHeader and
   /// adjusts the branches to branch to the vector preheader or \p Bypass,
   /// depending on the generated condition.
-  BasicBlock *emitSCEVChecks(BasicBlock *Bypass,
-                             BasicBlock *LoopVectorPreHeader) {
+  std::pair<Value *, BasicBlock *> emitSCEVChecks() {
     using namespace llvm::PatternMatch;
     if (!SCEVCheckCond || match(SCEVCheckCond, m_ZeroInt()))
-      return nullptr;
+      return {nullptr, nullptr};
 
-    auto *Pred = LoopVectorPreHeader->getSinglePredecessor();
-    BranchInst::Create(LoopVectorPreHeader, SCEVCheckBlock);
-
-    SCEVCheckBlock->getTerminator()->eraseFromParent();
-    SCEVCheckBlock->moveBefore(LoopVectorPreHeader);
-    Pred->getTerminator()->replaceSuccessorWith(LoopVectorPreHeader,
-                                                SCEVCheckBlock);
-
-    BranchInst &BI =
-        *BranchInst::Create(Bypass, LoopVectorPreHeader, SCEVCheckCond);
-    if (AddBranchWeights)
-      setBranchWeights(BI, SCEVCheckBypassWeights, /*IsExpected=*/false);
-    ReplaceInstWithInst(SCEVCheckBlock->getTerminator(), &BI);
     AddedAnyChecks = true;
-    return SCEVCheckBlock;
+    return {SCEVCheckCond , SCEVCheckBlock};
   }
 
   /// Adds the generated MemCheckBlock before \p LoopVectorPreHeader and adjusts
   /// the branches to branch to the vector preheader or \p Bypass, depending on
   /// the generated condition.
-  BasicBlock *emitMemRuntimeChecks(BasicBlock *Bypass,
-                                   BasicBlock *LoopVectorPreHeader) {
+  std::pair<Value *, BasicBlock *> emitMemRuntimeChecks() {
     // Check if we generated code that checks in runtime if arrays overlap.
     if (!MemRuntimeCheckCond)
-      return nullptr;
-
-    auto *Pred = LoopVectorPreHeader->getSinglePredecessor();
-    Pred->getTerminator()->replaceSuccessorWith(LoopVectorPreHeader,
-                                                MemCheckBlock);
-
-    MemCheckBlock->moveBefore(LoopVectorPreHeader);
-
-    BranchInst &BI =
-        *BranchInst::Create(Bypass, LoopVectorPreHeader, MemRuntimeCheckCond);
-    if (AddBranchWeights) {
-      setBranchWeights(BI, MemCheckBypassWeights, /*IsExpected=*/false);
-    }
-    ReplaceInstWithInst(MemCheckBlock->getTerminator(), &BI);
-    MemCheckBlock->getTerminator()->setDebugLoc(
-        Pred->getTerminator()->getDebugLoc());
+      return {nullptr, nullptr};
 
     AddedAnyChecks = true;
-    return MemCheckBlock;
+    return {MemRuntimeCheckCond, MemCheckBlock};
   }
 
+  BasicBlock *getSCEVCheckBlock() const { return SCEVCheckBlock; }
+  BasicBlock *getMemCheckBlock() const { return MemCheckBlock; }
+
   /// Return true if any runtime checks have been added
   bool hasChecks() const { return AddedAnyChecks; }
----------------
ayalz wrote:

```suggestion
  bool hasChecks() const { return MemRuntimeCheckCond || (SCEVCheckCond && !match(SCEVCheckCond, m_ZeroInt())); }
```
?

https://github.com/llvm/llvm-project/pull/143879