[llvm] [VPlan] Model first memory runtime checks as VPlan recipes. (PR #221483)

[Ramkumar Ramachandra via llvm-commits]

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@@ -1459,54 +1460,6 @@ static void insertCheckBlockBeforeVectorLoop(VPlan &Plan,
   addIncomingForLastPredecessor(ScalarPH);
 }
 
-void VPlanTransforms::modelGeneratedMainLoopBlocks(
-    VPlan &EpiPlan, VPlan &MainPlan, VPIRBasicBlock *EnteredFrom) {
-  // Map blocks from MainPlan to new, empty VPIRBasicBlocks in EpiPlan, so the
-  // skeleton CFG can be modeled explicitly. MainPlan's entry maps to EpiPlan's
-  // now-disconnected entry and its scalar PH to EnteredFrom.
-  VPBlockBase *MainEntry = MainPlan.getEntry();
-  VPBlockBase *MainScalarPH = MainPlan.getScalarPreheader();
-  SmallMapVector<VPBlockBase *, VPBlockBase *, 8> MainToEpiVPBB;
-  MainToEpiVPBB[MainEntry] = EpiPlan.getEntry();
-  ReversePostOrderTraversal<VPBlockShallowTraversalWrapper<VPBlockBase *>> RPOT(
-      MainEntry);
-  for (VPIRBasicBlock *VPBB : VPBlockUtils::blocksAs<VPIRBasicBlock>(RPOT))
-    // Skip entry block and exit blocks/scalar loop header; they are already
-    // modeled in the epilogue plan.
-    if (VPBB != MainEntry && VPBB != MainScalarPH && VPBB->hasSuccessors())
-      MainToEpiVPBB[VPBB] =
-          EpiPlan.createEmptyVPIRBasicBlock(VPBB->getIRBasicBlock());
-  MainToEpiVPBB[MainScalarPH] = EnteredFrom;
-
-  // First, connect the edges from the bypass blocks (minimum iteration checks,
-  // runtime checks) to the scalar preheader, in reverse order, to preserve the
-  // predecessor order of the generated IR.
-  VPBasicBlock *EpiScalarPH = EpiPlan.getScalarPreheader();
-  for (VPBlockBase *MainVPBB :
-       reverse(drop_end(drop_begin(MainScalarPH->predecessors())))) {
-    VPBlockUtils::connectBlocks(MainToEpiVPBB.lookup(MainVPBB), EpiScalarPH);
-    addIncomingForLastPredecessor(EpiScalarPH);
-  }
-
-  // Mirror MainPlan's CFG, skipping the bypass edges connected above, which
-  // come first, and edges to blocks not modeled in EpiPlan.
-  for (auto &[MainVPBB, EpiVPBB] : drop_end(MainToEpiVPBB))
-    for (VPBlockBase *Succ :
-         drop_begin(MainVPBB->getSuccessors(), EpiVPBB->getNumSuccessors()))
-      if (auto *SuccVPBB = MainToEpiVPBB.lookup(Succ))
-        VPBlockUtils::connectBlocks(EpiVPBB, SuccVPBB);
-
-  // EnteredFrom is the only modeled block with phis; re-use the incoming values
-  // its IR phis already have for the new predecessors.
-  for (VPRecipeBase &R : EnteredFrom->phis()) {
-    auto *PhiR = cast<VPIRPhi>(&R);
----------------
artagnon wrote:

Hm, not sure how this change is related? Isn't this min-iteration-count-check, which is unrelated to mem-checks entirely?

https://github.com/llvm/llvm-project/pull/221483