[VPlan] Remove VPWidenRecipe constructor with no underlying instruction. NFCI (llvm#166521)

My understanding is that a VPWidenRecipe should be used for recipes with
an exact underlying scalar instruction, and VPInstruction should be used
elsewhere e.g. for instructions generated as a part of the vectorization
process.

The only user of the VPWidenRecipe constructor that doesn't take an
underlying instruction is in adjustRecipesForReductions, but we can just
use VPInstruction there.

Author: lukel97

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -8807,9 +8807,9 @@ void LoopVectorizationPlanner::adjustRecipesForReductions(
                  match(CurrentLink, m_Sub(m_VPValue(), m_VPValue()))) {
         Type *PhiTy = TypeInfo.inferScalarType(PhiR);
         auto *Zero = Plan->getConstantInt(PhiTy, 0);
-        VPWidenRecipe *Sub = new VPWidenRecipe(
-            Instruction::Sub, {Zero, CurrentLink->getOperand(1)}, {},
-            VPIRMetadata(), CurrentLinkI->getDebugLoc());
+        auto *Sub = new VPInstruction(Instruction::Sub,
+                                      {Zero, CurrentLink->getOperand(1)}, {},
+                                      {}, CurrentLinkI->getDebugLoc());
         Sub->setUnderlyingValue(CurrentLinkI);
         LinkVPBB->insert(Sub, CurrentLink->getIterator());
         VecOp = Sub;

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -1010,7 +1010,7 @@ class VPIRMetadata {
       Metadata.emplace_back(Kind, Node);
   }
 
-  /// Intersect this VPIRMetada object with \p MD, keeping only metadata
+  /// Intersect this VPIRMetadata object with \p MD, keeping only metadata
   /// nodes that are common to both.
   void intersect(const VPIRMetadata &MD);
 
@@ -1515,12 +1515,6 @@ class LLVM_ABI_FOR_TEST VPWidenRecipe : public VPRecipeWithIRFlags,
   unsigned Opcode;
 
 public:
-  VPWidenRecipe(unsigned Opcode, ArrayRef<VPValue *> Operands,
-                const VPIRFlags &Flags, const VPIRMetadata &Metadata,
-                DebugLoc DL)
-      : VPRecipeWithIRFlags(VPDef::VPWidenSC, Operands, Flags, DL),
-        VPIRMetadata(Metadata), Opcode(Opcode) {}
-
   VPWidenRecipe(Instruction &I, ArrayRef<VPValue *> Operands,
                 const VPIRFlags &Flags = {}, const VPIRMetadata &Metadata = {},
                 DebugLoc DL = {})
@@ -1532,10 +1526,8 @@ class LLVM_ABI_FOR_TEST VPWidenRecipe : public VPRecipeWithIRFlags,
   ~VPWidenRecipe() override = default;
 
   VPWidenRecipe *clone() override {
-    auto *R =
-        new VPWidenRecipe(getOpcode(), operands(), *this, *this, getDebugLoc());
-    R->setUnderlyingValue(getUnderlyingValue());
-    return R;
+    return new VPWidenRecipe(*getUnderlyingInstr(), operands(), *this, *this,
+                             getDebugLoc());
   }
 
   VP_CLASSOF_IMPL(VPDef::VPWidenSC)