[SPIRV] fix alloca -> OpVariable lowering

fixes #163777

Test was written with help from Copilot

Author: simeonschaub

llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp

@@ -1706,7 +1706,7 @@ void SPIRVEmitIntrinsics::replacePointerOperandWithPtrCast(
       return;
     } else if (isTodoType(Pointer)) {
       eraseTodoType(Pointer);
-      if (!isa<CallInst>(Pointer) && !isa<GetElementPtrInst>(Pointer)) {
+      if (!isa<CallInst>(Pointer) && !isa<GetElementPtrInst>(Pointer) && !isa<AllocaInst>(Pointer)) {
         //  If this wouldn't be the first spv_ptrcast but existing type info is
         //  uncomplete, update spv_assign_ptr_type arguments.
         if (CallInst *AssignCI = GR->findAssignPtrTypeInstr(Pointer)) {

llvm/test/CodeGen/SPIRV/alloca-aggregate-type.ll

@@ -0,0 +1,36 @@
+; Test that alloca with aggregate type generates correct OpVariable
+; with the array type as the pointee, not a pointer-to-pointer type
+;
+; This test verifies that when we have an alloca of an array containing
+; structs with pointers, the OpVariable uses the correct array type
+; instead of incorrectly using a pointer-to-pointer type.
+
+; RUN: llc -O0 -mtriple=spirv64-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
+; CHECK-DAG: %[[#Int8:]] = OpTypeInt 8 0
+; CHECK-DAG: %[[#Int64:]] = OpTypeInt 64 0
+; CHECK-DAG: %[[#Int32:]] = OpTypeInt 32 0
+; CHECK-DAG: %[[#One:]] = OpConstant %[[#Int32]] 1
+; CHECK-DAG: %[[#Two:]] = OpConstant %[[#Int32]] 2
+; CHECK-DAG: %[[#PtrCross:]] = OpTypePointer CrossWorkgroup %[[#Int8]]
+; CHECK-DAG: %[[#Array1:]] = OpTypeArray %[[#Int64]] %[[#One]]
+; CHECK-DAG: %[[#Struct1:]] = OpTypeStruct %[[#PtrCross]] %[[#Int64]] %[[#Array1]] %[[#Int64]]
+; CHECK-DAG: %[[#Array2:]] = OpTypeArray %[[#Array1]] %[[#Two]]
+; CHECK-DAG: %[[#Struct2:]] = OpTypeStruct %[[#Struct1]] %[[#Array2]]
+; CHECK-DAG: %[[#Struct3:]] = OpTypeStruct %[[#Struct2]]
+; CHECK-DAG: %[[#ArrayStruct:]] = OpTypeArray %[[#Struct3]] %[[#One]]
+; CHECK-DAG: %[[#PtrFunc:]] = OpTypePointer Function %[[#ArrayStruct]]
+
+; Verify OpVariable uses the array type, not pointer-to-pointer
+; CHECK: %[[#Var:]] = OpVariable %[[#PtrFunc]] Function
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-G1"
+target triple = "spirv64-unknown-unknown"
+
+define spir_kernel void @test_alloca_aggregate() local_unnamed_addr {
+entry:
+  %y = alloca [1 x { { { ptr addrspace(1), i64, [1 x i64], i64 }, [2 x [1 x i64]] } }], align 8
+  %ptr = load ptr addrspace(1), ptr %y, align 8
+  ret void
+}