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Author: Mel-Chen

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -1263,7 +1263,9 @@ class VPInstruction : public VPRecipeWithIRFlags {
     // for all lanes, depending on its uses).
     PtrAdd,
     // Selects elements from two vectors (second and third operand) based on a
-    // condition vector (first operand) and a pivot index (fourth operand).
+    // condition vector (first operand) and a pivot index (fourth operand). The
+    // lanes whose positions are greater than or equal to the pivot are taken
+    // from the third operand.
     MergeUntilPivot,
   };
 

llvm/lib/Transforms/Vectorize/VPlanPatternMatch.h

@@ -54,7 +54,7 @@ template <typename Class> struct bind_ty {
 struct specificval_ty {
   const VPValue *Val;
 
-  specificval_ty(const VPValue *V) : Val(V) {} //std::move?
+  specificval_ty(const VPValue *V) : Val(V) {}
 
   bool match(VPValue *VPV) { return VPV == Val; }
 };

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -681,7 +681,6 @@ Value *VPInstruction::generatePerPart(VPTransformState &State, unsigned Part) {
     Value *OnFalse = State.get(getOperand(2), Part);
     Value *Pivot = State.get(getOperand(3), VPIteration(0, 0));
     assert(Pivot->getType()->isIntegerTy() && "Pivot should be an integer.");
-
     return Builder.CreateIntrinsic(Intrinsic::vp_merge, {OnTrue->getType()},
                                    {Cond, OnTrue, OnFalse, Pivot}, nullptr,
                                    Name);

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -1491,7 +1491,6 @@ bool VPlanTransforms::tryAddExplicitVectorLength(VPlan &Plan) {
         NewRecipe = new VPReductionEVLRecipe(*RedR, *VPEVL,
                                              GetNewMask(RedR->getCondOp()));
       } else if (auto *VPInst = dyn_cast<VPInstruction>(CurRecipe)) {
-
         VPValue *LHS, *RHS;
         if (match(VPInst, m_Select(m_Specific(HeaderMask), m_VPValue(LHS),
                                    m_VPValue(RHS)))) {