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

[Luke Lau via llvm-commits]

https://github.com/lukel97 created https://github.com/llvm/llvm-project/pull/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.


>From 7c047d9b7b11b8609a2f15ef0e32498fa8346abd Mon Sep 17 00:00:00 2001
From: Luke Lau <luke at igalia.com>
Date: Wed, 5 Nov 2025 17:08:33 +0800
Subject: [PATCH] [VPlan] Remove VPWidenRecipe constructor with no underlying
 instruction. NFCI

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.
---
 llvm/lib/Transforms/Vectorize/LoopVectorize.cpp |  6 +++---
 llvm/lib/Transforms/Vectorize/VPlan.h           | 11 ++---------
 2 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index e5c3f17860103..c19d348ff1205 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -8641,9 +8641,9 @@ void LoopVectorizationPlanner::adjustRecipesForReductions(
                  CurrentLinkI->getOpcode() == Instruction::Sub) {
         Type *PhiTy = PhiR->getUnderlyingValue()->getType();
         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;
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index cfe1f1e9d7528..0d51ea412acd1 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1447,12 +1447,6 @@ 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)
       : VPRecipeWithIRFlags(VPDef::VPWidenSC, Operands, I), VPIRMetadata(I),
         Opcode(I.getOpcode()) {}
@@ -1460,9 +1454,8 @@ 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());
+    auto *R = new VPWidenRecipe(*getUnderlyingInstr(), operands());
+    R->transferFlags(*this);
     return R;
   }