[llvm] [VPlan] Compute cost for most opcodes in VPWidenRecipe (NFCI). (PR #98764)

[Renato Golin via llvm-commits]

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@@ -1137,6 +1137,80 @@ void VPWidenRecipe::execute(VPTransformState &State) {
 #endif
 }
 
+InstructionCost VPWidenRecipe::computeCost(ElementCount VF,
+                                           VPCostContext &Ctx) const {
+  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
+  switch (Opcode) {
+  case Instruction::FNeg: {
+    Type *VectorTy =
+        ToVectorTy(Ctx.Types.inferScalarType(this->getVPSingleValue()), VF);
+    return Ctx.TTI.getArithmeticInstrCost(
+        Opcode, VectorTy, CostKind,
+        {TargetTransformInfo::OK_AnyValue, TargetTransformInfo::OP_None},
+        {TargetTransformInfo::OK_AnyValue, TargetTransformInfo::OP_None});
+  }
+
+  case Instruction::UDiv:
+  case Instruction::SDiv:
+  case Instruction::SRem:
+  case Instruction::URem:
+    // More complex computation, let the legacy cost-model handle this for now.
+    return Ctx.getLegacyCost(cast<Instruction>(getUnderlyingValue()), VF);
+  case Instruction::Add:
+  case Instruction::FAdd:
+  case Instruction::Sub:
+  case Instruction::FSub:
+  case Instruction::Mul:
+  case Instruction::FMul:
+  case Instruction::FDiv:
+  case Instruction::FRem:
+  case Instruction::Shl:
+  case Instruction::LShr:
+  case Instruction::AShr:
+  case Instruction::And:
+  case Instruction::Or:
+  case Instruction::Xor: {
+    VPValue *Op2 = getOperand(1);
----------------
rengolin wrote:

nit: `RHS`?

https://github.com/llvm/llvm-project/pull/98764