[llvm] [SPIR-V] Prevent type change of GEP results in type inference (PR #129250)

[Vyacheslav Levytskyy via llvm-commits]

https://github.com/VyacheslavLevytskyy created https://github.com/llvm/llvm-project/pull/129250

The following reproducer demonstrates the issue with invalid definition of GEP results during type inference

```
define spir_kernel void @foo(i1 %fl, i64 %idx, ptr addrspace(1) %dest, ptr addrspace(3) %src) {
  %p1 = getelementptr inbounds i8, ptr addrspace(1) %dest, i64 %idx
  %res = tail call spir_func target("spirv.Event") @_Z22__spirv_GroupAsyncCopyjPU3AS1iPU3AS3Kimm9ocl_event(i32 2, ptr addrspace(1) %p1, ptr addrspace(3) %src, i64 128, i64 1, target("spirv.Event") zeroinitializer)
  ret void
}

declare dso_local spir_func target("spirv.Event") @_Z22__spirv_GroupAsyncCopyjPU3AS1iPU3AS3Kimm9ocl_event(i32, ptr addrspace(1), ptr addrspace(3), i64, i64, target("spirv.Event"))
```

Here `OpGroupAsyncCopy` expects i32* arguments and type inference fails to set a correct type of the GEP result `%p1`, because it is an argument of `OpGroupAsyncCopy`.

This PR fixes the issue by preventing type change of GEP results in type inference.

>From 3aa9980ed41d2841d61ac1698d1e8a560779a27f Mon Sep 17 00:00:00 2001
From: "Levytskyy, Vyacheslav" <vyacheslav.levytskyy at intel.com>
Date: Fri, 28 Feb 2025 06:13:22 -0800
Subject: [PATCH] Prevent type change of GEP results in type inference

---
 llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp |  4 ++++
 .../SPIRV/pointers/ptr-access-chain-type.ll   | 24 +++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 llvm/test/CodeGen/SPIRV/pointers/ptr-access-chain-type.ll

diff --git a/llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp b/llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp
index 5dfba8427258f..bedd454b34a36 100644
--- a/llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp
@@ -2307,6 +2307,7 @@ bool SPIRVEmitIntrinsics::processFunctionPointers(Module &M) {
 
 // Apply types parsed from demangled function declarations.
 void SPIRVEmitIntrinsics::applyDemangledPtrArgTypes(IRBuilder<> &B) {
+  DenseMap<Function *, CallInst *> Ptrcasts;
   for (auto It : FDeclPtrTys) {
     Function *F = It.first;
     for (auto *U : F->users()) {
@@ -2326,6 +2327,9 @@ void SPIRVEmitIntrinsics::applyDemangledPtrArgTypes(IRBuilder<> &B) {
             B.SetCurrentDebugLocation(DebugLoc());
             buildAssignPtr(B, ElemTy, Arg);
           }
+        } else if (isa<GetElementPtrInst>(Param)) {
+          replaceUsesOfWithSpvPtrcast(Param, normalizeType(ElemTy), CI,
+                                      Ptrcasts);
         } else if (isa<Instruction>(Param)) {
           GR->addDeducedElementType(Param, normalizeType(ElemTy));
           // insertAssignTypeIntrs() will complete buildAssignPtr()
diff --git a/llvm/test/CodeGen/SPIRV/pointers/ptr-access-chain-type.ll b/llvm/test/CodeGen/SPIRV/pointers/ptr-access-chain-type.ll
new file mode 100644
index 0000000000000..d69959609c9dc
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/pointers/ptr-access-chain-type.ll
@@ -0,0 +1,24 @@
+; RUN: llc -verify-machineinstrs -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: %[[#Char:]] = OpTypeInt 8 0
+; CHECK-DAG: %[[#Long:]] = OpTypeInt 32 0
+; CHECK-DAG: %[[#CharPtr:]] = OpTypePointer CrossWorkgroup %[[#Char]]
+; CHECK-DAG: %[[#LongPtr:]] = OpTypePointer CrossWorkgroup %[[#Long]]
+; CHECK-DAG: %[[#LongPtrWG:]] = OpTypePointer Workgroup %[[#Long]]
+; CHECK: OpFunction
+; CHECK: OpFunctionParameter
+; CHECK: %[[#Dest:]] = OpFunctionParameter %[[#CharPtr]]
+; CHECK: %[[#Src:]] = OpFunctionParameter %[[#LongPtrWG]]
+; CHECK: %[[#InDest:]] = OpInBoundsPtrAccessChain %[[#CharPtr]] %[[#Dest]] %[[#]]
+; CHECK: %[[#InDestCasted:]] = OpBitcast %[[#LongPtr]] %[[#InDest]]
+; CHECK: OpGroupAsyncCopy %[[#]] %[[#]] %[[#InDestCasted]] %[[#Src]] %[[#]] %[[#]] %[[#]]
+
+define spir_kernel void @foo(i64 %idx, ptr addrspace(1) %dest, ptr addrspace(3) %src) {
+  %p1 = getelementptr inbounds i8, ptr addrspace(1) %dest, i64 %idx
+  %res = tail call spir_func target("spirv.Event") @_Z22__spirv_GroupAsyncCopyjPU3AS1iPU3AS3Kimm9ocl_event(i32 2, ptr addrspace(1) %p1, ptr addrspace(3) %src, i64 128, i64 1, target("spirv.Event") zeroinitializer)
+  ret void
+}
+
+; For this test case the mangling is important.
+declare dso_local spir_func target("spirv.Event") @_Z22__spirv_GroupAsyncCopyjPU3AS1iPU3AS3Kimm9ocl_event(i32, ptr addrspace(1), ptr addrspace(3), i64, i64, target("spirv.Event"))