[llvm] [VPlan] Cleanup and generalize VPIRMetadata CastInfo (NFC) (PR #190162)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon created https://github.com/llvm/llvm-project/pull/190162

None

>From 05251c342b126ffbf918f46544c6aca3b41976f2 Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <artagnon at tenstorrent.com>
Date: Thu, 2 Apr 2026 13:17:16 +0100
Subject: [PATCH] [VPlan] Cleanup and generalize VPIRMetadata CastInfo (NFC)

---
 llvm/lib/Transforms/Vectorize/VPlan.h | 98 ++++++++++++---------------
 1 file changed, 44 insertions(+), 54 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index ab47d927942db..a0e8ac95c0b30 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -4196,45 +4196,14 @@ template <>
 struct CastInfo<VPPhiAccessors, const VPRecipeBase *>
     : CastInfoVPPhiAccessors<const VPRecipeBase *> {};
 
-/// Casting from (const) VPRecipeBase -> (const) VPIRMetadata is supported for
-/// all recipe types implementing VPIRMetadata. Used by isa<> & co.
-namespace detail {
-template <typename DstTy, typename RecipeBasePtrTy>
-static inline auto castToVPIRMetadata(RecipeBasePtrTy R) -> DstTy {
-  switch (R->getVPRecipeID()) {
-  case VPRecipeBase::VPInstructionSC:
-    return cast<VPInstruction>(R);
-  case VPRecipeBase::VPWidenSC:
-    return cast<VPWidenRecipe>(R);
-  case VPRecipeBase::VPWidenCastSC:
-    return cast<VPWidenCastRecipe>(R);
-  case VPRecipeBase::VPWidenIntrinsicSC:
-    return cast<VPWidenIntrinsicRecipe>(R);
-  case VPRecipeBase::VPWidenCallSC:
-    return cast<VPWidenCallRecipe>(R);
-  case VPRecipeBase::VPReplicateSC:
-    return cast<VPReplicateRecipe>(R);
-  case VPRecipeBase::VPInterleaveSC:
-  case VPRecipeBase::VPInterleaveEVLSC:
-    return cast<VPInterleaveBase>(R);
-  case VPRecipeBase::VPWidenLoadSC:
-  case VPRecipeBase::VPWidenLoadEVLSC:
-  case VPRecipeBase::VPWidenStoreSC:
-  case VPRecipeBase::VPWidenStoreEVLSC:
-    return cast<VPWidenMemoryRecipe>(R);
-  default:
-    llvm_unreachable("invalid recipe for VPIRMetadata cast");
-  }
-}
-} // namespace detail
-
-/// Support casting from VPRecipeBase -> VPIRMetadata, by down-casting to the
-/// recipe types implementing VPIRMetadata. Used by cast<>, dyn_cast<> & co.
-template <typename DstTy, typename SrcTy>
-struct CastInfoVPIRMetadata : public CastIsPossible<DstTy, SrcTy> {
-  static inline bool isPossible(SrcTy R) {
-    // NOTE: Each recipe inheriting from VPIRMetadata must be listed here and
-    // also handled in castToVPIRMetadata.
+/// Support casting from VPRecipeBase -> VPIRMetadata.
+template <>
+struct CastInfo<VPIRMetadata, VPRecipeBase *>
+    : public DefaultDoCastIfPossible<VPIRMetadata *, VPRecipeBase *,
+                                     CastInfo<VPIRMetadata, VPRecipeBase *>> {
+  /// Used by isa.
+  static inline bool isPossible(VPRecipeBase *R) {
+    // NOTE: Each recipe inheriting from VPIRMetadata must be listed here.
     return isa<VPInstruction, VPWidenRecipe, VPWidenCastRecipe,
                VPWidenIntrinsicRecipe, VPWidenCallRecipe, VPReplicateRecipe,
                VPInterleaveRecipe, VPInterleaveEVLRecipe, VPWidenLoadRecipe,
@@ -4242,26 +4211,47 @@ struct CastInfoVPIRMetadata : public CastIsPossible<DstTy, SrcTy> {
         R);
   }
 
-  using RetTy = DstTy *;
-
-  /// doCast is used by cast<>.
-  static inline RetTy doCast(SrcTy R) {
-    return detail::castToVPIRMetadata<RetTy, SrcTy>(R);
+  /// Used by cast.
+  static inline VPIRMetadata *doCast(VPRecipeBase *R) {
+    switch (R->getVPRecipeID()) {
+    case VPRecipeBase::VPInstructionSC:
+      return cast<VPInstruction>(R);
+    case VPRecipeBase::VPWidenSC:
+      return cast<VPWidenRecipe>(R);
+    case VPRecipeBase::VPWidenCastSC:
+      return cast<VPWidenCastRecipe>(R);
+    case VPRecipeBase::VPWidenIntrinsicSC:
+      return cast<VPWidenIntrinsicRecipe>(R);
+    case VPRecipeBase::VPWidenCallSC:
+      return cast<VPWidenCallRecipe>(R);
+    case VPRecipeBase::VPReplicateSC:
+      return cast<VPReplicateRecipe>(R);
+    case VPRecipeBase::VPInterleaveSC:
+    case VPRecipeBase::VPInterleaveEVLSC:
+      return cast<VPInterleaveBase>(R);
+    case VPRecipeBase::VPWidenLoadSC:
+    case VPRecipeBase::VPWidenLoadEVLSC:
+    case VPRecipeBase::VPWidenStoreSC:
+    case VPRecipeBase::VPWidenStoreEVLSC:
+      return cast<VPWidenMemoryRecipe>(R);
+    default:
+      llvm_unreachable("Illegal recipe for VPIRMetadata cast");
+    }
   }
 
-  /// doCastIfPossible is used by dyn_cast<>.
-  static inline RetTy doCastIfPossible(SrcTy R) {
-    if (!isPossible(R))
-      return nullptr;
-    return doCast(R);
-  }
+  /// Used by inherited doCastIfPossible to dyn_cast.
+  static inline VPIRMetadata *castFailed() { return nullptr; }
 };
-template <>
-struct CastInfo<VPIRMetadata, VPRecipeBase *>
-    : CastInfoVPIRMetadata<VPIRMetadata, VPRecipeBase *> {};
+
 template <>
 struct CastInfo<VPIRMetadata, const VPRecipeBase *>
-    : CastInfoVPIRMetadata<const VPIRMetadata, const VPRecipeBase *> {};
+    : public ConstStrippingForwardingCast<
+          VPIRMetadata, const VPRecipeBase *,
+          CastInfo<VPIRMetadata, VPRecipeBase *>> {};
+template <>
+struct CastInfo<VPIRMetadata, VPRecipeBase>
+    : public ForwardToPointerCast<VPIRMetadata, VPRecipeBase *,
+                                  CastInfo<VPIRMetadata, VPRecipeBase *>> {};
 
 /// VPBasicBlock serves as the leaf of the Hierarchical Control-Flow Graph. It
 /// holds a sequence of zero or more VPRecipe's each representing a sequence of