[llvm] 94dc0a0 - [NFC][AMDGPU] Drop recursive types in LowerBufferFatPointers (#137735)

[via llvm-commits]

Author: Krzysztof Drewniak
Date: 2025-04-29T07:23:40-07:00
New Revision: 94dc0a0e7bc723af13a0923aa102fcc4d03c82a2

URL: https://github.com/llvm/llvm-project/commit/94dc0a0e7bc723af13a0923aa102fcc4d03c82a2
DIFF: https://github.com/llvm/llvm-project/commit/94dc0a0e7bc723af13a0923aa102fcc4d03c82a2.diff

LOG: [NFC][AMDGPU] Drop recursive types in LowerBufferFatPointers (#137735)

Now that IRMover and the rest of LLVM don't allow recursive types, drop
support for them from the clone of the IRMover code used when lowering
buffer fat pointer operations.

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp b/llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp
index 7163ad2aa7dca..284f6ede2b85b 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp
@@ -267,7 +267,7 @@ namespace {
 class BufferFatPtrTypeLoweringBase : public ValueMapTypeRemapper {
   DenseMap<Type *, Type *> Map;
 
-  Type *remapTypeImpl(Type *Ty, SmallPtrSetImpl<StructType *> &Seen);
+  Type *remapTypeImpl(Type *Ty);
 
 protected:
   virtual Type *remapScalar(PointerType *PT) = 0;
@@ -305,8 +305,7 @@ class BufferFatPtrToStructTypeMap : public BufferFatPtrTypeLoweringBase {
 } // namespace
 
 // This code is adapted from the type remapper in lib/Linker/IRMover.cpp
-Type *BufferFatPtrTypeLoweringBase::remapTypeImpl(
-    Type *Ty, SmallPtrSetImpl<StructType *> &Seen) {
+Type *BufferFatPtrTypeLoweringBase::remapTypeImpl(Type *Ty) {
   Type **Entry = &Map[Ty];
   if (*Entry)
     return *Entry;
@@ -331,18 +330,11 @@ Type *BufferFatPtrTypeLoweringBase::remapTypeImpl(
   // require recursion.
   if (Ty->getNumContainedTypes() == 0 && IsUniqued)
     return *Entry = Ty;
-  if (!IsUniqued) {
-    // Create a dummy type for recursion purposes.
-    if (!Seen.insert(TyAsStruct).second) {
-      StructType *Placeholder = StructType::create(Ty->getContext());
-      return *Entry = Placeholder;
-    }
-  }
   bool Changed = false;
   SmallVector<Type *> ElementTypes(Ty->getNumContainedTypes(), nullptr);
   for (unsigned int I = 0, E = Ty->getNumContainedTypes(); I < E; ++I) {
     Type *OldElem = Ty->getContainedType(I);
-    Type *NewElem = remapTypeImpl(OldElem, Seen);
+    Type *NewElem = remapTypeImpl(OldElem);
     ElementTypes[I] = NewElem;
     Changed |= (OldElem != NewElem);
   }
@@ -366,13 +358,6 @@ Type *BufferFatPtrTypeLoweringBase::remapTypeImpl(
       return *Entry = StructType::get(Ty->getContext(), ElementTypes, IsPacked);
     SmallString<16> Name(STy->getName());
     STy->setName("");
-    Type **RecursionEntry = &Map[Ty];
-    if (*RecursionEntry) {
-      auto *Placeholder = cast<StructType>(*RecursionEntry);
-      Placeholder->setBody(ElementTypes, IsPacked);
-      Placeholder->setName(Name);
-      return *Entry = Placeholder;
-    }
     return *Entry = StructType::create(Ty->getContext(), ElementTypes, Name,
                                        IsPacked);
   }
@@ -380,8 +365,7 @@ Type *BufferFatPtrTypeLoweringBase::remapTypeImpl(
 }
 
 Type *BufferFatPtrTypeLoweringBase::remapType(Type *SrcTy) {
-  SmallPtrSet<StructType *, 2> Visited;
-  return remapTypeImpl(SrcTy, Visited);
+  return remapTypeImpl(SrcTy);
 }
 
 Type *BufferFatPtrToStructTypeMap::remapScalar(PointerType *PT) {