Opt: Remove dependency on VPWidenIntOrFpInductionRecipe and expend VPVectorPointerRecipe

Author: Mel-Chen

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -3627,9 +3627,9 @@ void LoopVectorizationCostModel::collectLoopUniforms(ElementCount VF) {
     if (IsUniformMemOpUse(I))
       return true;
 
-    return (WideningDecision == CM_Widen ||
-            WideningDecision == CM_Widen_Reverse ||
-            WideningDecision == CM_Interleave);
+    return (
+        WideningDecision == CM_Widen || WideningDecision == CM_Widen_Reverse ||
+        WideningDecision == CM_Strided || WideningDecision == CM_Interleave);
   };
 
   // Returns true if Ptr is the pointer operand of a memory access instruction
@@ -8367,17 +8367,27 @@ VPRecipeBuilder::tryToWidenMemory(Instruction *I, ArrayRef<VPValue *> Operands,
   // reverse consecutive.
   LoopVectorizationCostModel::InstWidening Decision =
       CM.getWideningDecision(I, Range.Start);
+
+  auto SameWiden = [&](ElementCount VF) -> bool {
+    return Decision == CM.getWideningDecision(I, VF);
+  };
+  bool ContainsWidenVF =
+      LoopVectorizationPlanner::getDecisionAndClampRange(SameWiden, Range);
+  assert(ContainsWidenVF &&
+         "At least widen the memory accesses by the Start VF.");
+
   bool Reverse = Decision == LoopVectorizationCostModel::CM_Widen_Reverse;
   bool Consecutive =
       Reverse || Decision == LoopVectorizationCostModel::CM_Widen;
   bool Strided = Decision == LoopVectorizationCostModel::CM_Strided;
 
   VPValue *Ptr = isa<LoadInst>(I) ? Operands[0] : Operands[1];
-  if (Consecutive) {
+  if (Consecutive || Strided) {
     auto *GEP = dyn_cast<GetElementPtrInst>(
         Ptr->getUnderlyingValue()->stripPointerCasts());
     VPSingleDefRecipe *VectorPtr;
     if (Reverse) {
+      assert(!Strided && "Reverse and Strided are mutually exclusive.");
       // When folding the tail, we may compute an address that we don't in the
       // original scalar loop and it may not be inbounds. Drop Inbounds in that
       // case.
@@ -8388,7 +8398,7 @@ VPRecipeBuilder::tryToWidenMemory(Instruction *I, ArrayRef<VPValue *> Operands,
       VectorPtr = new VPReverseVectorPointerRecipe(
           Ptr, &Plan.getVF(), getLoadStoreType(I), Flags, I->getDebugLoc());
     } else {
-      VectorPtr = new VPVectorPointerRecipe(Ptr, getLoadStoreType(I),
+      VectorPtr = new VPVectorPointerRecipe(Ptr, getLoadStoreType(I), Strided,
                                             GEP ? GEP->getNoWrapFlags()
                                                 : GEPNoWrapFlags::none(),
                                             I->getDebugLoc());

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -1568,12 +1568,15 @@ class VPVectorPointerRecipe : public VPRecipeWithIRFlags,
                               public VPUnrollPartAccessor<1> {
   Type *IndexedTy;
 
+  /// Indicate whether to compute the pointer for strided memory accesses.
+  bool Strided;
+
 public:
-  VPVectorPointerRecipe(VPValue *Ptr, Type *IndexedTy, GEPNoWrapFlags GEPFlags,
-                        DebugLoc DL)
+  VPVectorPointerRecipe(VPValue *Ptr, Type *IndexedTy, bool Strided,
+                        GEPNoWrapFlags GEPFlags, DebugLoc DL)
       : VPRecipeWithIRFlags(VPDef::VPVectorPointerSC, ArrayRef<VPValue *>(Ptr),
                             GEPFlags, DL),
-        IndexedTy(IndexedTy) {}
+        IndexedTy(IndexedTy), Strided(Strided) {}
 
   VP_CLASSOF_IMPL(VPDef::VPVectorPointerSC)
 
@@ -1594,7 +1597,7 @@ class VPVectorPointerRecipe : public VPRecipeWithIRFlags,
   }
 
   VPVectorPointerRecipe *clone() override {
-    return new VPVectorPointerRecipe(getOperand(0), IndexedTy,
+    return new VPVectorPointerRecipe(getOperand(0), IndexedTy, Strided,
                                      getGEPNoWrapFlags(), getDebugLoc());
   }
 

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -2115,7 +2115,9 @@ void VPVectorPointerRecipe::execute(VPTransformState &State) {
                                 CurrentPart, Builder);
   Value *Ptr = State.get(getOperand(0), VPLane(0));
 
-  Value *Increment = createStepForVF(Builder, IndexTy, State.VF, CurrentPart);
+  // TODO: Support non-unit-reverse strided accesses.
+  int64_t Step = Strided ? -1 * CurrentPart : CurrentPart;
+  Value *Increment = createStepForVF(Builder, IndexTy, State.VF, Step);
   Value *ResultPtr =
       Builder.CreateGEP(IndexedTy, Ptr, Increment, "", getGEPNoWrapFlags());