[llvm] [VPlan] Manage created blocks directly in VPlan. (NFC) (PR #120918)

[via llvm-commits]

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@@ -822,32 +814,33 @@ void VPRegionBlock::print(raw_ostream &O, const Twine &Indent,
 #endif
 
 VPlan::VPlan(Loop *L) {
-  setEntry(VPIRBasicBlock::fromBasicBlock(L->getLoopPreheader()));
-  ScalarHeader = VPIRBasicBlock::fromBasicBlock(L->getHeader());
+  setEntry(createVPIRBasicBlock(L->getLoopPreheader()));
+  ScalarHeader = createVPIRBasicBlock(L->getHeader());
 }
 
 VPlan::~VPlan() {
-  if (Entry) {
-    VPValue DummyValue;
-    for (VPBlockBase *Block : vp_depth_first_shallow(Entry))
-      Block->dropAllReferences(&DummyValue);
-
-    VPBlockBase::deleteCFG(Entry);
+  VPValue DummyValue;
+
+  for (auto *VPB : CreatedBlocks) {
+    if (auto *VPBB = dyn_cast<VPBasicBlock>(VPB)) {
+      // Replace all operands of recipes and all VPValues defined in VPBB with
+      // DummyValue so the block can be deleted.
+      for (VPRecipeBase &R : *VPBB) {
+        for (auto *Def : R.definedValues())
+          Def->replaceAllUsesWith(&DummyValue);
+
+        for (unsigned I = 0, E = R.getNumOperands(); I != E; I++)
+          R.setOperand(I, &DummyValue);
+      }
+    }
+    delete VPB;
   }
   for (VPValue *VPV : VPLiveInsToFree)
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ayalz wrote:

nit: `CreatedBlocks` >> `VPBlocksToFree` would be more consistent with `VPLiveInsToFree`.

https://github.com/llvm/llvm-project/pull/120918