[llvm] [VPlan] Implement VPWidenCastRecipe::computeCost(). (NFCI) (PR #111339)

[Elvis Wang via llvm-commits]

================
@@ -1462,6 +1462,57 @@ void VPWidenCastRecipe::execute(VPTransformState &State) {
   State.addMetadata(Cast, cast_or_null<Instruction>(getUnderlyingValue()));
 }
 
+InstructionCost VPWidenCastRecipe::computeCost(ElementCount VF,
+                                               VPCostContext &Ctx) const {
+  // Computes the CastContextHint from a recipes that may access memory.
+  auto ComputeCCH = [&](const VPRecipeBase *R) -> TTI::CastContextHint {
+    if (VF.isScalar())
+      return TTI::CastContextHint::Normal;
+    if (isa<VPInterleaveRecipe>(R))
+      return TTI::CastContextHint::Interleave;
+    if (const auto *ReplicateRecipe = dyn_cast<VPReplicateRecipe>(R))
+      return ReplicateRecipe->isPredicated() ? TTI::CastContextHint::Masked
+                                             : TTI::CastContextHint::Normal;
+    const auto *WidenMemoryRecipe = dyn_cast<VPWidenMemoryRecipe>(R);
+    if (WidenMemoryRecipe == nullptr)
+      return TTI::CastContextHint::None;
+    if (!WidenMemoryRecipe->isConsecutive())
+      return TTI::CastContextHint::GatherScatter;
+    if (WidenMemoryRecipe->isReverse())
+      return TTI::CastContextHint::Reversed;
+    if (WidenMemoryRecipe->isMasked())
+      return TTI::CastContextHint::Masked;
+    return TTI::CastContextHint::Normal;
+  };
+
+  VPValue *Operand = getOperand(0);
+  TTI::CastContextHint CCH = TTI::CastContextHint::None;
+  // For Trunc, the context is the only user, which must be a
+  // VPWidenStoreRecipe, a VPInterleaveRecipe ,or a VPReplicateRecipe.
----------------
ElvisWang123 wrote:

Fixed, thanks.

https://github.com/llvm/llvm-project/pull/111339