[llvm] [SPIRV] Legalize byte-buffer reinterpretation ptrcasts (#192523) (PR #212999)

Tim Corringham via llvm-commits llvm-commits at lists.llvm.org
Tue Aug 4 07:47:26 PDT 2026


https://github.com/tcorringham updated https://github.com/llvm/llvm-project/pull/212999

>From c7cae9554aa3819bcc9dcf97d6497e4a6ffaacff Mon Sep 17 00:00:00 2001
From: Tim Corringham <tcorring at amd.com>
Date: Thu, 30 Jul 2026 11:25:37 +0100
Subject: [PATCH 1/6] [HLSL][SPIRV] Legalize reinterpretation ptrcasts for
 byte-addressable buffers

When SPIR-V emit-intrinsics inserts an i8->T spv_ptrcast for typed
loads/stores through byte-addressable resource pointers, legalize the
access directly on the original pointer instead of asserting.

Fixes Clang/Vulkan compilation of RWByteAddressBuffer and local resource
array tests (issue #192523).

Co-authored-by: Cursor
---
 .../Target/SPIRV/SPIRVLegalizePointerCast.cpp | 71 ++++++++++++++++---
 .../SPIRV/passes/SPIRVLegalizePointerCast.ll  | 31 ++++++++
 .../pointers/byte-address-buffer-store.ll     | 17 +++++
 3 files changed, 111 insertions(+), 8 deletions(-)
 create mode 100644 llvm/test/CodeGen/SPIRV/pointers/byte-address-buffer-store.ll

diff --git a/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp b/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
index 847eda7880c03..c332666bc86fb 100644
--- a/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
@@ -222,15 +222,59 @@ class SPIRVLegalizePointerCastImpl {
     return std::make_pair(GEP, CurrentTy);
   }
 
+  // Returns the pointer operand of a load/store that uses a ptrcast.
+  static Value *getCastedPointerOperand(Instruction *MemI) {
+    if (auto *LI = dyn_cast<LoadInst>(MemI))
+      return LI->getPointerOperand();
+    if (auto *SI = dyn_cast<StoreInst>(MemI))
+      return SI->getPointerOperand();
+    if (auto *II = dyn_cast<IntrinsicInst>(MemI))
+      if (II->getIntrinsicID() == Intrinsic::spv_store)
+        return II->getArgOperand(1);
+    llvm_unreachable("Unexpected memory instruction being legalized.");
+  }
+
+  // Legalizes a reinterpretation ptrcast: the casted pointer's pointee type
+  // matches the access type but differs from the original pointer layout (e.g.
+  // byte-addressable i8 storage accessed as i32).
+  template <typename MemInstTy>
+  bool tryDirectReinterpretAccess(IRBuilder<> &B, Type *AccessTy,
+                                  Value *OriginalPtr, Value *CastedPtr,
+                                  Align Alignment, bool IsStore,
+                                  Value *StoreSrc, MemInstTy *BadMem) {
+    Type *CastedElemTy = GR->findDeducedElementType(CastedPtr);
+    if (!CastedElemTy || CastedElemTy != AccessTy)
+      return false;
+
+    GR->buildAssignPtr(B, CastedElemTy, OriginalPtr);
+    if (IsStore) {
+      StoreInst *SI = B.CreateStore(StoreSrc, OriginalPtr);
+      SI->setAlignment(Alignment);
+    } else {
+      LoadInst *LI = B.CreateLoad(AccessTy, OriginalPtr);
+      LI->setAlignment(Alignment);
+      buildAssignType(B, AccessTy, LI);
+      GR->replaceAllUsesWith(BadMem, LI, /* DeleteOld= */ true);
+      DeadInstructions.push_back(BadMem);
+    }
+    return true;
+  }
+
   // Builds a legalized load from a pointer, drilling down through
   // memory layouts to find a compatible type. Load flags will be
   // copied from |BadLoad|, which should be the load being legalized.
   Value *buildLegalizedLoad(IRBuilder<> &B, Type *ElementType, Value *Source,
-                            LoadInst *BadLoad) {
+                            LoadInst *BadLoad, Value *CastedPtr) {
     auto ResultOpt = getPointerToFirstCompatibleType(
         B, Source, BadLoad->getPointerOperandType(), ElementType, false);
-    assert(ResultOpt && "Failed to load from aggregate: "
-                        "Could not find compatible memory layout.");
+    if (!ResultOpt) {
+      if (tryDirectReinterpretAccess(
+              B, ElementType, Source, CastedPtr, BadLoad->getAlign(),
+              /*IsStore=*/false, /*StoreSrc=*/nullptr, BadLoad))
+        return nullptr;
+      llvm_unreachable("Failed to load from aggregate: "
+                       "Could not find compatible memory layout.");
+    }
     auto [GEP, CurrentTy] = *ResultOpt;
 
     auto *SAT = dyn_cast<ArrayType>(CurrentTy);
@@ -415,7 +459,10 @@ class SPIRVLegalizePointerCastImpl {
     Type *ToTy = GR->findDeducedElementType(CastedOperand);
     B.SetInsertPoint(LI);
 
-    Value *Output = buildLegalizedLoad(B, ToTy, OriginalOperand, LI);
+    Value *Output =
+        buildLegalizedLoad(B, ToTy, OriginalOperand, LI, CastedOperand);
+    if (!Output)
+      return;
 
     GR->replaceAllUsesWith(LI, Output, /* DeleteOld= */ true);
     DeadInstructions.push_back(LI);
@@ -513,11 +560,18 @@ class SPIRVLegalizePointerCastImpl {
   // Builds a legalized store to a pointer, drilling down through
   // memory layouts to find a compatible type.
   void buildLegalizedStore(IRBuilder<> &B, Value *Src, Value *Dst,
-                           Align Alignment) {
+                           Align Alignment, Value *CastedPtr,
+                           Instruction *BadStore) {
     auto ResultOpt = getPointerToFirstCompatibleType(B, Dst, Dst->getType(),
                                                      Src->getType(), true);
-    assert(ResultOpt && "Failed to store to aggregate: "
-                        "Could not find compatible memory layout.");
+    if (!ResultOpt) {
+      if (tryDirectReinterpretAccess(B, Src->getType(), Dst, CastedPtr,
+                                     Alignment,
+                                     /*IsStore=*/true, Src, BadStore))
+        return;
+      llvm_unreachable("Failed to store to aggregate: "
+                       "Could not find compatible memory layout.");
+    }
     auto [GEP, CurrentTy] = *ResultOpt;
 
     auto *DAT = dyn_cast<ArrayType>(CurrentTy);
@@ -552,7 +606,8 @@ class SPIRVLegalizePointerCastImpl {
   void transformStore(IRBuilder<> &B, Instruction *BadStore, Value *Src,
                       Value *Dst, Align Alignment) {
     B.SetInsertPoint(BadStore);
-    buildLegalizedStore(B, Src, Dst, Alignment);
+    buildLegalizedStore(B, Src, Dst, Alignment,
+                        getCastedPointerOperand(BadStore), BadStore);
     DeadInstructions.push_back(BadStore);
   }
 
diff --git a/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll b/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
index a03dc58c5a5b6..4b988807d0062 100644
--- a/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
+++ b/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
@@ -76,3 +76,34 @@ entry:
 }
 
 attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+ at .str = private unnamed_addr constant [4 x i8] c"Buf\00", align 1
+
+declare target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32, i32, i32, i32, ptr)
+declare ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0), i32)
+
+; Byte-addressable VulkanBuffer getpointer is typed as i8, but typed
+; scalar loads/stores add an i8->T spv_ptrcast. Legalize that by storing
+; directly through the getpointer result.
+
+define spir_func void @byteBufferStore() #0 {
+; CHECK-LABEL: define spir_func void @byteBufferStore(
+; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
+; CHECK: store i32 42, ptr addrspace(11)
+entry:
+  %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
+  %ptr = call ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, i32 0)
+  store i32 42, ptr addrspace(11) %ptr, align 4
+  ret void
+}
+
+define spir_func void @byteBufferLoad() #0 {
+; CHECK-LABEL: define spir_func void @byteBufferLoad(
+; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
+; CHECK: load i32, ptr addrspace(11)
+entry:
+  %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
+  %ptr = call ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, i32 0)
+  %val = load i32, ptr addrspace(11) %ptr, align 4
+  ret void
+}
diff --git a/llvm/test/CodeGen/SPIRV/pointers/byte-address-buffer-store.ll b/llvm/test/CodeGen/SPIRV/pointers/byte-address-buffer-store.ll
new file mode 100644
index 0000000000000..6eaba6f548619
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/pointers/byte-address-buffer-store.ll
@@ -0,0 +1,17 @@
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv-unknown-vulkan-compute %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-vulkan-compute %s -o - -filetype=obj | spirv-val %}
+
+; CHECK: OpAccessChain
+; CHECK: OpStore
+
+ at .str = private unnamed_addr constant [4 x i8] c"Buf\00", align 1
+
+define void @main() local_unnamed_addr #0 {
+entry:
+  %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
+  %ptr = tail call noundef align 4 dereferenceable(4) ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, i32 0)
+  store i32 42, ptr addrspace(11) %ptr, align 4
+  ret void
+}
+
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }

>From e2d509caa4588156b34bd68ee12405b11fe78810 Mon Sep 17 00:00:00 2001
From: Tim Corringham <tcorring at amd.com>
Date: Thu, 30 Jul 2026 12:52:34 +0100
Subject: [PATCH 2/6] Extend test for issue #192523

Extended the test coverage to include the same def-use chain as seen in
the failure case reported in #192523.
---
 .../SPIRV/passes/SPIRVLegalizePointerCast.ll  | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll b/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
index 4b988807d0062..4a34d82ddd812 100644
--- a/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
+++ b/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
@@ -107,3 +107,22 @@ entry:
   %val = load i32, ptr addrspace(11) %ptr, align 4
   ret void
 }
+
+ at slot = internal global target("spirv.VulkanBuffer", [0 x i8], 12, 0) poison, align 8
+
+; Regression for issue #192523: handle flows through memory before getpointer
+; (as in local RWByteAddressBuffer arrays), then typed store hits i8->i32 ptrcast.
+
+define spir_func void @byteBufferStoreViaLoadedHandle() #0 {
+; CHECK-LABEL: define spir_func void @byteBufferStoreViaLoadedHandle(
+; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
+; CHECK: load target("spirv.VulkanBuffer", [0 x i8], 12, 0), ptr @slot
+; CHECK: store i32 42, ptr addrspace(11)
+entry:
+  %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
+  store target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, ptr @slot, align 8
+  %loaded = load target("spirv.VulkanBuffer", [0 x i8], 12, 0), ptr @slot, align 8
+  %ptr = call ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0) %loaded, i32 0)
+  store i32 42, ptr addrspace(11) %ptr, align 4
+  ret void
+}

>From 0745d64caf161ff714eeeed51393e74eb9ced129 Mon Sep 17 00:00:00 2001
From: Tim Corringham <tcorring at amd.com>
Date: Thu, 30 Jul 2026 13:19:06 +0100
Subject: [PATCH 3/6] [SPIRV] Clarify and extend byte-buffer ptrcast
 legalization tests

Document that [0 x i8] is a storage-buffer layout type, not an HLSL surface
type. Drop unneeded HLSL function attributes from the byte-buffer cases and
add a loaded-handle load regression alongside the existing store path.

Co-authored-by: Cursor
---
 .../SPIRV/passes/SPIRVLegalizePointerCast.ll  | 39 ++++++++++++++-----
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll b/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
index 4a34d82ddd812..706b1ef2c4dcb 100644
--- a/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
+++ b/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
@@ -82,12 +82,17 @@ attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
 declare target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32, i32, i32, i32, ptr)
 declare ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0), i32)
 
-; Byte-addressable VulkanBuffer getpointer is typed as i8, but typed
-; scalar loads/stores add an i8->T spv_ptrcast. Legalize that by storing
-; directly through the getpointer result.
-
-define spir_func void @byteBufferStore() #0 {
-; CHECK-LABEL: define spir_func void @byteBufferStore(
+; Byte-addressable buffer tests model Clang's SPIR-V resource layout for HLSL
+; ByteAddressBuffer/RWByteAddressBuffer: the handle carries [0 x i8] as the
+; OpTypeRuntimeArray element type for storage-buffer blocks. That i8 names
+; byte-addressable layout in LLVM IR; it is not an HLSL surface type. Typed
+; HLSL accesses (e.g. Store(offset, uint)) lower to i32 load/store at a byte
+; offset in getpointer's index operand. emit-intrinsics tags getpointer as i8
+; from the layout, then inserts i8->T spv_ptrcast for the typed access;
+; legalize-pointer-cast removes the ptrcast and keeps the typed access.
+
+define void @byteBufferStore() {
+; CHECK-LABEL: define void @byteBufferStore(
 ; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
 ; CHECK: store i32 42, ptr addrspace(11)
 entry:
@@ -97,8 +102,8 @@ entry:
   ret void
 }
 
-define spir_func void @byteBufferLoad() #0 {
-; CHECK-LABEL: define spir_func void @byteBufferLoad(
+define void @byteBufferLoad() {
+; CHECK-LABEL: define void @byteBufferLoad(
 ; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
 ; CHECK: load i32, ptr addrspace(11)
 entry:
@@ -113,8 +118,8 @@ entry:
 ; Regression for issue #192523: handle flows through memory before getpointer
 ; (as in local RWByteAddressBuffer arrays), then typed store hits i8->i32 ptrcast.
 
-define spir_func void @byteBufferStoreViaLoadedHandle() #0 {
-; CHECK-LABEL: define spir_func void @byteBufferStoreViaLoadedHandle(
+define void @byteBufferStoreViaLoadedHandle() {
+; CHECK-LABEL: define void @byteBufferStoreViaLoadedHandle(
 ; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
 ; CHECK: load target("spirv.VulkanBuffer", [0 x i8], 12, 0), ptr @slot
 ; CHECK: store i32 42, ptr addrspace(11)
@@ -126,3 +131,17 @@ entry:
   store i32 42, ptr addrspace(11) %ptr, align 4
   ret void
 }
+
+define void @byteBufferLoadViaLoadedHandle() {
+; CHECK-LABEL: define void @byteBufferLoadViaLoadedHandle(
+; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
+; CHECK: load target("spirv.VulkanBuffer", [0 x i8], 12, 0), ptr @slot
+; CHECK: load i32, ptr addrspace(11)
+entry:
+  %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
+  store target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, ptr @slot, align 8
+  %loaded = load target("spirv.VulkanBuffer", [0 x i8], 12, 0), ptr @slot, align 8
+  %ptr = call ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0) %loaded, i32 0)
+  %val = load i32, ptr addrspace(11) %ptr, align 4
+  ret void
+}

>From d7dacfb283b3564191840fd341c3a6db89593784 Mon Sep 17 00:00:00 2001
From: Tim Corringham <tcorring at amd.com>
Date: Thu, 30 Jul 2026 17:15:29 +0100
Subject: [PATCH 4/6] [SPIRV] Legalize byte-buffer ptrcasts with per-byte
 scalar and vector access

Emit valid uchar storage-buffer access chains by lowering typed scalar
and vector loads/stores to byte-wise i8 accesses via getpointer offsets,
instead of retagging pointers to the access type.

Co-authored-by: Cursor
---
 .../Target/SPIRV/SPIRVLegalizePointerCast.cpp | 170 ++++++++++++++++++
 .../SPIRV/passes/SPIRVLegalizePointerCast.ll  |  39 +++-
 .../pointers/byte-address-buffer-load4.ll     |  20 +++
 3 files changed, 225 insertions(+), 4 deletions(-)
 create mode 100644 llvm/test/CodeGen/SPIRV/pointers/byte-address-buffer-load4.ll

diff --git a/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp b/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
index c332666bc86fb..7a80959158ea8 100644
--- a/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
@@ -234,6 +234,159 @@ class SPIRVLegalizePointerCastImpl {
     llvm_unreachable("Unexpected memory instruction being legalized.");
   }
 
+  static bool isByteLayoutType(Type *Ty, LLVMContext &Ctx) {
+    return Ty == Type::getInt8Ty(Ctx);
+  }
+
+  static IntrinsicInst *getResourceGetPointer(Value *Ptr) {
+    if (auto *II = dyn_cast<IntrinsicInst>(Ptr))
+      if (II->getIntrinsicID() == Intrinsic::spv_resource_getpointer)
+        return II;
+    return nullptr;
+  }
+
+  Value *gepByteOffset(IRBuilder<> &B, Value *BasePtr, Type *I8Ty,
+                       unsigned ByteOffset) {
+    if (ByteOffset == 0)
+      return BasePtr;
+
+    IntrinsicInst *GetPtr = getResourceGetPointer(BasePtr);
+    assert(GetPtr &&
+           "byte layout pointer must come from spv.resource.getpointer");
+
+    Value *Handle = GetPtr->getOperand(0);
+    Value *BaseOffset = GetPtr->getOperand(1);
+    Value *NewOffset = BaseOffset;
+    if (ByteOffset != 0) {
+      if (auto *CI = dyn_cast<ConstantInt>(BaseOffset))
+        NewOffset = ConstantInt::get(CI->getType(),
+                                     CI->getZExtValue() + ByteOffset);
+      else
+        NewOffset = B.CreateAdd(
+            BaseOffset, ConstantInt::get(BaseOffset->getType(), ByteOffset));
+    }
+    SmallVector<OperandBundleDef, 1> OpBundles;
+    GetPtr->getOperandBundlesAsDefs(OpBundles);
+    CallInst *NewPtr = B.CreateCall(GetPtr->getFunctionType(),
+                                    GetPtr->getCalledOperand(),
+                                    {Handle, NewOffset}, OpBundles);
+    NewPtr->setAttributes(GetPtr->getAttributes());
+    NewPtr->setCallingConv(GetPtr->getCallingConv());
+    GR->buildAssignPtr(B, I8Ty, NewPtr);
+    return NewPtr;
+  }
+
+  Value *bitcastScalarToInt(IRBuilder<> &B, Value *Scalar) {
+    Type *Ty = Scalar->getType();
+    const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
+    Type *IntTy =
+        IntegerType::get(B.getContext(), DL.getTypeStoreSizeInBits(Ty));
+    if (Ty == IntTy)
+      return Scalar;
+    if (Ty->isIntOrIntVectorTy())
+      return B.CreateIntCast(Scalar, IntTy, /*isSigned=*/false);
+    return B.CreateBitCast(Scalar, IntTy);
+  }
+
+  Value *bitcastIntToScalar(IRBuilder<> &B, Value *IntVal, Type *ScalarTy) {
+    if (IntVal->getType() == ScalarTy)
+      return IntVal;
+    if (ScalarTy->isIntOrIntVectorTy())
+      return B.CreateIntCast(IntVal, ScalarTy, /*isSigned=*/false);
+    return B.CreateBitCast(IntVal, ScalarTy);
+  }
+
+  void storeScalarToByteLayout(IRBuilder<> &B, Value *Src, Value *Dst,
+                             Align Alignment) {
+    LLVMContext &Ctx = B.getContext();
+    Type *I8Ty = Type::getInt8Ty(Ctx);
+    const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
+    Value *IntVal = bitcastScalarToInt(B, Src);
+    buildAssignType(B, IntVal->getType(), IntVal);
+    unsigned NumBytes = DL.getTypeStoreSize(Src->getType());
+
+    for (unsigned I = 0; I < NumBytes; ++I) {
+      Value *Shifted =
+          I == 0 ? IntVal
+                 : B.CreateLShr(IntVal, ConstantInt::get(IntVal->getType(), 8 * I));
+      if (I != 0)
+        buildAssignType(B, IntVal->getType(), Shifted);
+      Value *Byte = B.CreateTrunc(Shifted, I8Ty);
+      buildAssignType(B, I8Ty, Byte);
+      Value *Ptr = gepByteOffset(B, Dst, I8Ty, I);
+      StoreInst *SI = B.CreateStore(Byte, Ptr);
+      SI->setAlignment(commonAlignment(Alignment, I));
+    }
+  }
+
+  void storeValueToByteLayout(IRBuilder<> &B, Value *Src, Value *Dst,
+                              Align Alignment) {
+    if (auto *VT = dyn_cast<FixedVectorType>(Src->getType())) {
+      const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
+      Type *I8Ty = Type::getInt8Ty(B.getContext());
+      unsigned ElemSize = DL.getTypeStoreSize(VT->getElementType());
+      for (unsigned I = 0; I < VT->getNumElements(); ++I) {
+        Value *Elem = extractScalarFromVector(B, Src, I);
+        Value *ElemPtr = gepByteOffset(B, Dst, I8Ty, I * ElemSize);
+        storeScalarToByteLayout(B, Elem, ElemPtr,
+                                commonAlignment(Alignment, I * ElemSize));
+      }
+      return;
+    }
+    storeScalarToByteLayout(B, Src, Dst, Alignment);
+  }
+
+  Value *loadScalarFromByteLayout(IRBuilder<> &B, Type *AccessTy, Value *Src,
+                                  Align Alignment) {
+    LLVMContext &Ctx = B.getContext();
+    Type *I8Ty = Type::getInt8Ty(Ctx);
+    const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
+    unsigned NumBytes = DL.getTypeStoreSize(AccessTy);
+    Type *IntTy = IntegerType::get(Ctx, DL.getTypeStoreSizeInBits(AccessTy));
+    Value *IntVal = ConstantInt::get(IntTy, 0);
+
+    for (unsigned I = 0; I < NumBytes; ++I) {
+      Value *Ptr = gepByteOffset(B, Src, I8Ty, I);
+      LoadInst *LI = B.CreateLoad(I8Ty, Ptr);
+      LI->setAlignment(commonAlignment(Alignment, I));
+      buildAssignType(B, I8Ty, LI);
+      Value *Extended = B.CreateZExt(LI, IntTy);
+      buildAssignType(B, IntTy, Extended);
+      Value *Shifted =
+          I == 0 ? Extended
+                 : B.CreateShl(Extended, ConstantInt::get(IntTy, 8 * I));
+      if (I != 0)
+        buildAssignType(B, IntTy, Shifted);
+      IntVal = I == 0 ? Shifted : B.CreateOr(IntVal, Shifted);
+      buildAssignType(B, IntTy, IntVal);
+    }
+
+    Value *Result = bitcastIntToScalar(B, IntVal, AccessTy);
+    if (Result != IntVal)
+      buildAssignType(B, AccessTy, Result);
+    return Result;
+  }
+
+  Value *loadValueFromByteLayout(IRBuilder<> &B, Type *AccessTy, Value *Src,
+                                 Align Alignment) {
+    if (auto *VT = dyn_cast<FixedVectorType>(AccessTy)) {
+      const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
+      Type *I8Ty = Type::getInt8Ty(B.getContext());
+      unsigned ElemSize = DL.getTypeStoreSize(VT->getElementType());
+      SmallVector<Value *, 4> LoadedElements;
+      for (unsigned I = 0; I < VT->getNumElements(); ++I) {
+        Value *ElemPtr = gepByteOffset(B, Src, I8Ty, I * ElemSize);
+        Value *Elem = loadScalarFromByteLayout(
+            B, VT->getElementType(), ElemPtr,
+            commonAlignment(Alignment, I * ElemSize));
+        buildAssignType(B, VT->getElementType(), Elem);
+        LoadedElements.push_back(Elem);
+      }
+      return buildVectorFromLoadedElements(B, VT, LoadedElements);
+    }
+    return loadScalarFromByteLayout(B, AccessTy, Src, Alignment);
+  }
+
   // Legalizes a reinterpretation ptrcast: the casted pointer's pointee type
   // matches the access type but differs from the original pointer layout (e.g.
   // byte-addressable i8 storage accessed as i32).
@@ -246,6 +399,23 @@ class SPIRVLegalizePointerCastImpl {
     if (!CastedElemTy || CastedElemTy != AccessTy)
       return false;
 
+    Type *OriginalElemTy = GR->findDeducedElementType(OriginalPtr);
+    const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
+    if (OriginalElemTy && isByteLayoutType(OriginalElemTy, B.getContext()) &&
+        AccessTy->isSingleValueType() &&
+        DL.getTypeStoreSize(AccessTy) > 1) {
+      if (IsStore) {
+        storeValueToByteLayout(B, StoreSrc, OriginalPtr, Alignment);
+      } else {
+        Value *Loaded =
+            loadValueFromByteLayout(B, AccessTy, OriginalPtr, Alignment);
+        buildAssignType(B, AccessTy, Loaded);
+        GR->replaceAllUsesWith(BadMem, Loaded, /* DeleteOld= */ true);
+        DeadInstructions.push_back(BadMem);
+      }
+      return true;
+    }
+
     GR->buildAssignPtr(B, CastedElemTy, OriginalPtr);
     if (IsStore) {
       StoreInst *SI = B.CreateStore(StoreSrc, OriginalPtr);
diff --git a/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll b/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
index 706b1ef2c4dcb..eef986566e0e9 100644
--- a/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
+++ b/llvm/test/CodeGen/SPIRV/passes/SPIRVLegalizePointerCast.ll
@@ -94,7 +94,9 @@ declare ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuff
 define void @byteBufferStore() {
 ; CHECK-LABEL: define void @byteBufferStore(
 ; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
-; CHECK: store i32 42, ptr addrspace(11)
+; CHECK: store i8 42, ptr addrspace(11)
+; CHECK: call ptr addrspace(11) @llvm.spv.resource.getpointer{{.*}} i32 1)
+; CHECK: store i8 0, ptr addrspace(11)
 entry:
   %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
   %ptr = call ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, i32 0)
@@ -105,7 +107,9 @@ entry:
 define void @byteBufferLoad() {
 ; CHECK-LABEL: define void @byteBufferLoad(
 ; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
-; CHECK: load i32, ptr addrspace(11)
+; CHECK: load i8, ptr addrspace(11)
+; CHECK: call ptr addrspace(11) @llvm.spv.resource.getpointer{{.*}} i32 1)
+; CHECK: load i8, ptr addrspace(11)
 entry:
   %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
   %ptr = call ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, i32 0)
@@ -122,7 +126,8 @@ define void @byteBufferStoreViaLoadedHandle() {
 ; CHECK-LABEL: define void @byteBufferStoreViaLoadedHandle(
 ; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
 ; CHECK: load target("spirv.VulkanBuffer", [0 x i8], 12, 0), ptr @slot
-; CHECK: store i32 42, ptr addrspace(11)
+; CHECK: store i8 42, ptr addrspace(11)
+; CHECK: call ptr addrspace(11) @llvm.spv.resource.getpointer{{.*}} i32 1)
 entry:
   %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
   store target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, ptr @slot, align 8
@@ -136,7 +141,8 @@ define void @byteBufferLoadViaLoadedHandle() {
 ; CHECK-LABEL: define void @byteBufferLoadViaLoadedHandle(
 ; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
 ; CHECK: load target("spirv.VulkanBuffer", [0 x i8], 12, 0), ptr @slot
-; CHECK: load i32, ptr addrspace(11)
+; CHECK: load i8, ptr addrspace(11)
+; CHECK: call ptr addrspace(11) @llvm.spv.resource.getpointer{{.*}} i32 1)
 entry:
   %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
   store target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, ptr @slot, align 8
@@ -145,3 +151,28 @@ entry:
   %val = load i32, ptr addrspace(11) %ptr, align 4
   ret void
 }
+
+define void @byteBufferStore4() {
+; CHECK-LABEL: define void @byteBufferStore4(
+; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
+; CHECK: store i8
+; CHECK: call ptr addrspace(11) @llvm.spv.resource.getpointer{{.*}} i32 4)
+entry:
+  %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
+  %ptr = call ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, i32 0)
+  store <4 x i32> <i32 1, i32 2, i32 3, i32 4>, ptr addrspace(11) %ptr, align 16
+  ret void
+}
+
+define void @byteBufferLoad4() {
+; CHECK-LABEL: define void @byteBufferLoad4(
+; CHECK-NOT: call {{.*}}@llvm.spv.ptrcast
+; CHECK: load i8, ptr addrspace(11)
+; CHECK: call ptr addrspace(11) @llvm.spv.resource.getpointer{{.*}} i32 4)
+; CHECK: call {{.*}}@llvm.spv.insertelt
+entry:
+  %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
+  %ptr = call ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, i32 0)
+  %val = load <4 x i32>, ptr addrspace(11) %ptr, align 16
+  ret void
+}
diff --git a/llvm/test/CodeGen/SPIRV/pointers/byte-address-buffer-load4.ll b/llvm/test/CodeGen/SPIRV/pointers/byte-address-buffer-load4.ll
new file mode 100644
index 0000000000000..91aedb7df9d2a
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/pointers/byte-address-buffer-load4.ll
@@ -0,0 +1,20 @@
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv-unknown-vulkan-compute %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-vulkan-compute %s -o - -filetype=obj | spirv-val %}
+
+; CHECK: OpAccessChain
+; CHECK: OpLoad
+; CHECK-NOT: OpTypeVector
+
+ at .str = private unnamed_addr constant [4 x i8] c"Buf\00", align 1
+ at out = addrspace(10) global <4 x i32> zeroinitializer, align 16
+
+define void @main() local_unnamed_addr #0 {
+entry:
+  %handle = tail call target("spirv.VulkanBuffer", [0 x i8], 12, 0) @llvm.spv.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr nonnull @.str)
+  %ptr = tail call noundef align 16 dereferenceable(16) ptr addrspace(11) @llvm.spv.resource.getpointer(target("spirv.VulkanBuffer", [0 x i8], 12, 0) %handle, i32 0)
+  %val = load <4 x i32>, ptr addrspace(11) %ptr, align 16
+  store <4 x i32> %val, ptr addrspace(10) @out, align 16
+  ret void
+}
+
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }

>From 9caa8f4b578b2213689ac14265c8782e1ef871ee Mon Sep 17 00:00:00 2001
From: Tim Corringham <tcorring at amd.com>
Date: Mon, 3 Aug 2026 15:26:06 +0100
Subject: [PATCH 5/6] Update SPIR-V ptrcast legalization

Extend SPIRVLegalizePointerCast to legalize reinterpretation spv.ptrcasts
on byte-addressable buffers ([0 x i8] / RWByteAddressBuffer).
When Clang emits a typed load or store through such a pointer (e.g. i32,
<4 x i32>), the pass now lowers it to valid logical SPIR-V instead of
hitting an unreachable or producing invalid OpAccessChain into uchar
storage.

Co-authored-by: Cursor
---
 .../Target/SPIRV/SPIRVLegalizePointerCast.cpp | 220 ++++++++----------
 1 file changed, 103 insertions(+), 117 deletions(-)

diff --git a/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp b/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
index 7a80959158ea8..b0e4fcfb6dc2c 100644
--- a/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
@@ -222,22 +222,6 @@ class SPIRVLegalizePointerCastImpl {
     return std::make_pair(GEP, CurrentTy);
   }
 
-  // Returns the pointer operand of a load/store that uses a ptrcast.
-  static Value *getCastedPointerOperand(Instruction *MemI) {
-    if (auto *LI = dyn_cast<LoadInst>(MemI))
-      return LI->getPointerOperand();
-    if (auto *SI = dyn_cast<StoreInst>(MemI))
-      return SI->getPointerOperand();
-    if (auto *II = dyn_cast<IntrinsicInst>(MemI))
-      if (II->getIntrinsicID() == Intrinsic::spv_store)
-        return II->getArgOperand(1);
-    llvm_unreachable("Unexpected memory instruction being legalized.");
-  }
-
-  static bool isByteLayoutType(Type *Ty, LLVMContext &Ctx) {
-    return Ty == Type::getInt8Ty(Ctx);
-  }
-
   static IntrinsicInst *getResourceGetPointer(Value *Ptr) {
     if (auto *II = dyn_cast<IntrinsicInst>(Ptr))
       if (II->getIntrinsicID() == Intrinsic::spv_resource_getpointer)
@@ -245,8 +229,7 @@ class SPIRVLegalizePointerCastImpl {
     return nullptr;
   }
 
-  Value *gepByteOffset(IRBuilder<> &B, Value *BasePtr, Type *I8Ty,
-                       unsigned ByteOffset) {
+  Value *gepByteOffset(IRBuilder<> &B, Value *BasePtr, unsigned ByteOffset) {
     if (ByteOffset == 0)
       return BasePtr;
 
@@ -256,15 +239,13 @@ class SPIRVLegalizePointerCastImpl {
 
     Value *Handle = GetPtr->getOperand(0);
     Value *BaseOffset = GetPtr->getOperand(1);
-    Value *NewOffset = BaseOffset;
-    if (ByteOffset != 0) {
-      if (auto *CI = dyn_cast<ConstantInt>(BaseOffset))
-        NewOffset = ConstantInt::get(CI->getType(),
-                                     CI->getZExtValue() + ByteOffset);
-      else
-        NewOffset = B.CreateAdd(
-            BaseOffset, ConstantInt::get(BaseOffset->getType(), ByteOffset));
-    }
+    Value *NewOffset;
+    if (auto *CI = dyn_cast<ConstantInt>(BaseOffset))
+      NewOffset =
+          ConstantInt::get(CI->getType(), CI->getZExtValue() + ByteOffset);
+    else
+      NewOffset = B.CreateAdd(
+          BaseOffset, ConstantInt::get(BaseOffset->getType(), ByteOffset));
     SmallVector<OperandBundleDef, 1> OpBundles;
     GetPtr->getOperandBundlesAsDefs(OpBundles);
     CallInst *NewPtr = B.CreateCall(GetPtr->getFunctionType(),
@@ -272,6 +253,7 @@ class SPIRVLegalizePointerCastImpl {
                                     {Handle, NewOffset}, OpBundles);
     NewPtr->setAttributes(GetPtr->getAttributes());
     NewPtr->setCallingConv(GetPtr->getCallingConv());
+    Type *I8Ty = Type::getInt8Ty(B.getContext());
     GR->buildAssignPtr(B, I8Ty, NewPtr);
     return NewPtr;
   }
@@ -302,40 +284,20 @@ class SPIRVLegalizePointerCastImpl {
     Type *I8Ty = Type::getInt8Ty(Ctx);
     const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
     Value *IntVal = bitcastScalarToInt(B, Src);
-    buildAssignType(B, IntVal->getType(), IntVal);
     unsigned NumBytes = DL.getTypeStoreSize(Src->getType());
 
     for (unsigned I = 0; I < NumBytes; ++I) {
       Value *Shifted =
           I == 0 ? IntVal
                  : B.CreateLShr(IntVal, ConstantInt::get(IntVal->getType(), 8 * I));
-      if (I != 0)
-        buildAssignType(B, IntVal->getType(), Shifted);
       Value *Byte = B.CreateTrunc(Shifted, I8Ty);
       buildAssignType(B, I8Ty, Byte);
-      Value *Ptr = gepByteOffset(B, Dst, I8Ty, I);
+      Value *Ptr = gepByteOffset(B, Dst, I);
       StoreInst *SI = B.CreateStore(Byte, Ptr);
       SI->setAlignment(commonAlignment(Alignment, I));
     }
   }
 
-  void storeValueToByteLayout(IRBuilder<> &B, Value *Src, Value *Dst,
-                              Align Alignment) {
-    if (auto *VT = dyn_cast<FixedVectorType>(Src->getType())) {
-      const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
-      Type *I8Ty = Type::getInt8Ty(B.getContext());
-      unsigned ElemSize = DL.getTypeStoreSize(VT->getElementType());
-      for (unsigned I = 0; I < VT->getNumElements(); ++I) {
-        Value *Elem = extractScalarFromVector(B, Src, I);
-        Value *ElemPtr = gepByteOffset(B, Dst, I8Ty, I * ElemSize);
-        storeScalarToByteLayout(B, Elem, ElemPtr,
-                                commonAlignment(Alignment, I * ElemSize));
-      }
-      return;
-    }
-    storeScalarToByteLayout(B, Src, Dst, Alignment);
-  }
-
   Value *loadScalarFromByteLayout(IRBuilder<> &B, Type *AccessTy, Value *Src,
                                   Align Alignment) {
     LLVMContext &Ctx = B.getContext();
@@ -346,7 +308,7 @@ class SPIRVLegalizePointerCastImpl {
     Value *IntVal = ConstantInt::get(IntTy, 0);
 
     for (unsigned I = 0; I < NumBytes; ++I) {
-      Value *Ptr = gepByteOffset(B, Src, I8Ty, I);
+      Value *Ptr = gepByteOffset(B, Src, I);
       LoadInst *LI = B.CreateLoad(I8Ty, Ptr);
       LI->setAlignment(commonAlignment(Alignment, I));
       buildAssignType(B, I8Ty, LI);
@@ -367,80 +329,105 @@ class SPIRVLegalizePointerCastImpl {
     return Result;
   }
 
-  Value *loadValueFromByteLayout(IRBuilder<> &B, Type *AccessTy, Value *Src,
-                                 Align Alignment) {
-    if (auto *VT = dyn_cast<FixedVectorType>(AccessTy)) {
-      const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
-      Type *I8Ty = Type::getInt8Ty(B.getContext());
-      unsigned ElemSize = DL.getTypeStoreSize(VT->getElementType());
-      SmallVector<Value *, 4> LoadedElements;
-      for (unsigned I = 0; I < VT->getNumElements(); ++I) {
-        Value *ElemPtr = gepByteOffset(B, Src, I8Ty, I * ElemSize);
-        Value *Elem = loadScalarFromByteLayout(
-            B, VT->getElementType(), ElemPtr,
-            commonAlignment(Alignment, I * ElemSize));
-        buildAssignType(B, VT->getElementType(), Elem);
-        LoadedElements.push_back(Elem);
-      }
-      return buildVectorFromLoadedElements(B, VT, LoadedElements);
-    }
-    return loadScalarFromByteLayout(B, AccessTy, Src, Alignment);
-  }
+  enum class ReinterpretKind { None, ByteWise, RetagDirect };
 
-  // Legalizes a reinterpretation ptrcast: the casted pointer's pointee type
-  // matches the access type but differs from the original pointer layout (e.g.
-  // byte-addressable i8 storage accessed as i32).
-  template <typename MemInstTy>
-  bool tryDirectReinterpretAccess(IRBuilder<> &B, Type *AccessTy,
-                                  Value *OriginalPtr, Value *CastedPtr,
-                                  Align Alignment, bool IsStore,
-                                  Value *StoreSrc, MemInstTy *BadMem) {
+  // Classifies a ptrcast reinterpretation: casted pointee matches the access
+  // type but differs from the original storage layout (e.g. i8 byte buffer as
+  // i32). ByteWise means multi-byte access must use per-byte i8 load/store.
+  ReinterpretKind classifyReinterpretAccess(IRBuilder<> &B, Type *AccessTy,
+                                            Value *OriginalPtr,
+                                            Value *CastedPtr) {
     Type *CastedElemTy = GR->findDeducedElementType(CastedPtr);
     if (!CastedElemTy || CastedElemTy != AccessTy)
-      return false;
+      return ReinterpretKind::None;
 
     Type *OriginalElemTy = GR->findDeducedElementType(OriginalPtr);
     const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
-    if (OriginalElemTy && isByteLayoutType(OriginalElemTy, B.getContext()) &&
+    if (OriginalElemTy && OriginalElemTy == Type::getInt8Ty(B.getContext()) &&
         AccessTy->isSingleValueType() &&
-        DL.getTypeStoreSize(AccessTy) > 1) {
-      if (IsStore) {
-        storeValueToByteLayout(B, StoreSrc, OriginalPtr, Alignment);
+        DL.getTypeStoreSize(AccessTy) > 1)
+      return ReinterpretKind::ByteWise;
+
+    return ReinterpretKind::RetagDirect;
+  }
+
+  bool tryReinterpretLoad(IRBuilder<> &B, Type *AccessTy, Value *OriginalPtr,
+                          Value *CastedPtr, LoadInst *IllegalLoad) {
+    ReinterpretKind Kind =
+        classifyReinterpretAccess(B, AccessTy, OriginalPtr, CastedPtr);
+    if (Kind == ReinterpretKind::None)
+      return false;
+
+    Align Alignment = IllegalLoad->getAlign();
+    if (Kind == ReinterpretKind::ByteWise) {
+      const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
+      Value *Loaded;
+      if (auto *VT = dyn_cast<FixedVectorType>(AccessTy)) {
+        unsigned ElemSize = DL.getTypeStoreSize(VT->getElementType());
+        SmallVector<Value *, 4> LoadedElements;
+        for (unsigned I = 0; I < VT->getNumElements(); ++I) {
+          Value *ElemPtr = gepByteOffset(B, OriginalPtr, I * ElemSize);
+          LoadedElements.push_back(loadScalarFromByteLayout(
+              B, VT->getElementType(), ElemPtr,
+              commonAlignment(Alignment, I * ElemSize)));
+        }
+        Loaded = buildVectorFromLoadedElements(B, VT, LoadedElements);
       } else {
-        Value *Loaded =
-            loadValueFromByteLayout(B, AccessTy, OriginalPtr, Alignment);
+        Loaded = loadScalarFromByteLayout(B, AccessTy, OriginalPtr, Alignment);
         buildAssignType(B, AccessTy, Loaded);
-        GR->replaceAllUsesWith(BadMem, Loaded, /* DeleteOld= */ true);
-        DeadInstructions.push_back(BadMem);
       }
+      GR->replaceAllUsesWith(IllegalLoad, Loaded, /* DeleteOld= */ true);
+      DeadInstructions.push_back(IllegalLoad);
       return true;
     }
 
-    GR->buildAssignPtr(B, CastedElemTy, OriginalPtr);
-    if (IsStore) {
-      StoreInst *SI = B.CreateStore(StoreSrc, OriginalPtr);
-      SI->setAlignment(Alignment);
-    } else {
-      LoadInst *LI = B.CreateLoad(AccessTy, OriginalPtr);
-      LI->setAlignment(Alignment);
-      buildAssignType(B, AccessTy, LI);
-      GR->replaceAllUsesWith(BadMem, LI, /* DeleteOld= */ true);
-      DeadInstructions.push_back(BadMem);
+    GR->buildAssignPtr(B, AccessTy, OriginalPtr);
+    LoadInst *LI = B.CreateLoad(AccessTy, OriginalPtr);
+    LI->setAlignment(Alignment);
+    buildAssignType(B, AccessTy, LI);
+    GR->replaceAllUsesWith(IllegalLoad, LI, /* DeleteOld= */ true);
+    DeadInstructions.push_back(IllegalLoad);
+    return true;
+  }
+
+  bool tryReinterpretStore(IRBuilder<> &B, Type *AccessTy, Value *OriginalPtr,
+                           Value *CastedPtr, Value *StoreSrc, Align Alignment) {
+    ReinterpretKind Kind =
+        classifyReinterpretAccess(B, AccessTy, OriginalPtr, CastedPtr);
+    if (Kind == ReinterpretKind::None)
+      return false;
+
+    if (Kind == ReinterpretKind::ByteWise) {
+      const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
+      if (auto *VT = dyn_cast<FixedVectorType>(StoreSrc->getType())) {
+        unsigned ElemSize = DL.getTypeStoreSize(VT->getElementType());
+        for (unsigned I = 0; I < VT->getNumElements(); ++I) {
+          Value *Elem = extractScalarFromVector(B, StoreSrc, I);
+          Value *ElemPtr = gepByteOffset(B, OriginalPtr, I * ElemSize);
+          storeScalarToByteLayout(B, Elem, ElemPtr,
+                                  commonAlignment(Alignment, I * ElemSize));
+        }
+      } else {
+        storeScalarToByteLayout(B, StoreSrc, OriginalPtr, Alignment);
+      }
+      return true;
     }
+
+    GR->buildAssignPtr(B, AccessTy, OriginalPtr);
+    StoreInst *SI = B.CreateStore(StoreSrc, OriginalPtr);
+    SI->setAlignment(Alignment);
     return true;
   }
 
   // Builds a legalized load from a pointer, drilling down through
   // memory layouts to find a compatible type. Load flags will be
-  // copied from |BadLoad|, which should be the load being legalized.
+  // copied from |IllegalLoad|, which should be the load being legalized.
   Value *buildLegalizedLoad(IRBuilder<> &B, Type *ElementType, Value *Source,
-                            LoadInst *BadLoad, Value *CastedPtr) {
+                            LoadInst *IllegalLoad, Value *CastedPtr) {
     auto ResultOpt = getPointerToFirstCompatibleType(
-        B, Source, BadLoad->getPointerOperandType(), ElementType, false);
+        B, Source, IllegalLoad->getPointerOperandType(), ElementType, false);
     if (!ResultOpt) {
-      if (tryDirectReinterpretAccess(
-              B, ElementType, Source, CastedPtr, BadLoad->getAlign(),
-              /*IsStore=*/false, /*StoreSrc=*/nullptr, BadLoad))
+      if (tryReinterpretLoad(B, ElementType, Source, CastedPtr, IllegalLoad))
         return nullptr;
       llvm_unreachable("Failed to load from aggregate: "
                        "Could not find compatible memory layout.");
@@ -455,19 +442,20 @@ class SPIRVLegalizePointerCastImpl {
 
     if (ElementType == CurrentTy) {
       LoadInst *LI = B.CreateLoad(ElementType, GEP);
-      LI->setAlignment(BadLoad->getAlign());
+      LI->setAlignment(IllegalLoad->getAlign());
       buildAssignType(B, ElementType, LI);
       return LI;
     }
     if (SVT && DVT)
-      return loadVectorFromVector(B, SVT, DVT, GEP, BadLoad->getAlign());
+      return loadVectorFromVector(B, SVT, DVT, GEP, IllegalLoad->getAlign());
     if (SAT && DVT && SAT->getElementType() == DVT->getElementType())
-      return loadVectorFromArray(B, DVT, GEP, BadLoad->getAlign());
+      return loadVectorFromArray(B, DVT, GEP, IllegalLoad->getAlign());
     if (MAT && DVT && MAT->getElementType() == DVT->getElementType())
-      return loadVectorFromMatrixArray(B, DVT, GEP, MAT, BadLoad->getAlign());
+      return loadVectorFromMatrixArray(B, DVT, GEP, MAT, IllegalLoad->getAlign());
 
     llvm_unreachable("Failed to load from aggregate.");
   }
+
   Value *
   buildVectorFromLoadedElements(IRBuilder<> &B, FixedVectorType *TargetType,
                                 SmallVector<Value *, 4> &LoadedElements) {
@@ -527,6 +515,7 @@ class SPIRVLegalizePointerCastImpl {
     }
     return buildVectorFromLoadedElements(B, TargetType, LoadedElements);
   }
+
   // Loads elements from an array and constructs a vector.
   Value *loadVectorFromArray(IRBuilder<> &B, FixedVectorType *TargetType,
                              Value *Source, Align OriginalAlign) {
@@ -731,13 +720,11 @@ class SPIRVLegalizePointerCastImpl {
   // memory layouts to find a compatible type.
   void buildLegalizedStore(IRBuilder<> &B, Value *Src, Value *Dst,
                            Align Alignment, Value *CastedPtr,
-                           Instruction *BadStore) {
+                           Instruction *IllegalStore) {
     auto ResultOpt = getPointerToFirstCompatibleType(B, Dst, Dst->getType(),
                                                      Src->getType(), true);
     if (!ResultOpt) {
-      if (tryDirectReinterpretAccess(B, Src->getType(), Dst, CastedPtr,
-                                     Alignment,
-                                     /*IsStore=*/true, Src, BadStore))
+      if (tryReinterpretStore(B, Src->getType(), Dst, CastedPtr, Src, Alignment))
         return;
       llvm_unreachable("Failed to store to aggregate: "
                        "Could not find compatible memory layout.");
@@ -773,12 +760,11 @@ class SPIRVLegalizePointerCastImpl {
 
   // Transforms a store instruction (or SPV intrinsic) using a ptrcast as
   // operand into a valid logical SPIR-V store with no ptrcast.
-  void transformStore(IRBuilder<> &B, Instruction *BadStore, Value *Src,
-                      Value *Dst, Align Alignment) {
-    B.SetInsertPoint(BadStore);
-    buildLegalizedStore(B, Src, Dst, Alignment,
-                        getCastedPointerOperand(BadStore), BadStore);
-    DeadInstructions.push_back(BadStore);
+  void transformStore(IRBuilder<> &B, Instruction *IllegalStore, Value *Src,
+                      Value *Dst, Value *CastedOperand, Align Alignment) {
+    B.SetInsertPoint(IllegalStore);
+    buildLegalizedStore(B, Src, Dst, Alignment, CastedOperand, IllegalStore);
+    DeadInstructions.push_back(IllegalStore);
   }
 
   void legalizePointerCast(IntrinsicInst *II) {
@@ -798,7 +784,7 @@ class SPIRVLegalizePointerCastImpl {
 
       if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
         transformStore(B, SI, SI->getValueOperand(), OriginalOperand,
-                       SI->getAlign());
+                       CastedOperand, SI->getAlign());
         continue;
       }
 
@@ -819,7 +805,7 @@ class SPIRVLegalizePointerCastImpl {
           if (ConstantInt *C = dyn_cast<ConstantInt>(Intrin->getOperand(3)))
             Alignment = Align(C->getZExtValue());
           transformStore(B, Intrin, Intrin->getArgOperand(0), OriginalOperand,
-                         Alignment);
+                         CastedOperand, Alignment);
           continue;
         }
       }

>From 2bd7610de539240b68636ac0202427ad90aeb180 Mon Sep 17 00:00:00 2001
From: Tim Corringham <tcorring at amd.com>
Date: Tue, 4 Aug 2026 15:46:06 +0100
Subject: [PATCH 6/6] Fix clang-format issues

Correct code formatting.
---
 llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp b/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
index b0e4fcfb6dc2c..517a2b1a3ae1f 100644
--- a/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp
@@ -289,7 +289,8 @@ class SPIRVLegalizePointerCastImpl {
     for (unsigned I = 0; I < NumBytes; ++I) {
       Value *Shifted =
           I == 0 ? IntVal
-                 : B.CreateLShr(IntVal, ConstantInt::get(IntVal->getType(), 8 * I));
+                 : B.CreateLShr(IntVal,
+                                ConstantInt::get(IntVal->getType(), 8 * I));
       Value *Byte = B.CreateTrunc(Shifted, I8Ty);
       buildAssignType(B, I8Ty, Byte);
       Value *Ptr = gepByteOffset(B, Dst, I);
@@ -344,8 +345,7 @@ class SPIRVLegalizePointerCastImpl {
     Type *OriginalElemTy = GR->findDeducedElementType(OriginalPtr);
     const DataLayout &DL = B.GetInsertBlock()->getModule()->getDataLayout();
     if (OriginalElemTy && OriginalElemTy == Type::getInt8Ty(B.getContext()) &&
-        AccessTy->isSingleValueType() &&
-        DL.getTypeStoreSize(AccessTy) > 1)
+        AccessTy->isSingleValueType() && DL.getTypeStoreSize(AccessTy) > 1)
       return ReinterpretKind::ByteWise;
 
     return ReinterpretKind::RetagDirect;
@@ -451,7 +451,8 @@ class SPIRVLegalizePointerCastImpl {
     if (SAT && DVT && SAT->getElementType() == DVT->getElementType())
       return loadVectorFromArray(B, DVT, GEP, IllegalLoad->getAlign());
     if (MAT && DVT && MAT->getElementType() == DVT->getElementType())
-      return loadVectorFromMatrixArray(B, DVT, GEP, MAT, IllegalLoad->getAlign());
+      return loadVectorFromMatrixArray(B, DVT, GEP, MAT,
+                                       IllegalLoad->getAlign());
 
     llvm_unreachable("Failed to load from aggregate.");
   }
@@ -724,7 +725,8 @@ class SPIRVLegalizePointerCastImpl {
     auto ResultOpt = getPointerToFirstCompatibleType(B, Dst, Dst->getType(),
                                                      Src->getType(), true);
     if (!ResultOpt) {
-      if (tryReinterpretStore(B, Src->getType(), Dst, CastedPtr, Src, Alignment))
+      if (tryReinterpretStore(B, Src->getType(), Dst, CastedPtr, Src,
+                              Alignment))
         return;
       llvm_unreachable("Failed to store to aggregate: "
                        "Could not find compatible memory layout.");



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