[llvm] [AMDGPUAA] Check Type before Taking AddressSpace of a Value (PR #128116)

[via llvm-commits]

https://github.com/Chengjunp created https://github.com/llvm/llvm-project/pull/128116

In current `AMDGPUAAResult::alias`, we directly take the AddressSpace of `LocA.Ptr->getType()`. It's unsafe as `LocA.Ptr->getType()` may be a non-pointer type. 

This patch adds a check to ensure we only take AddressSpace on a pointer value. If either of `LocA.Ptr` or `LocB.Ptr` is non-pointer, we return `AliasResult::MayAlias` which is the most conservative result.

>From ca4ad2fe8ee60c0404322961916df20d11b93670 Mon Sep 17 00:00:00 2001
From: chengjunp <chengjunp at nvidia.com>
Date: Fri, 21 Feb 2025 03:01:07 +0000
Subject: [PATCH] Prevent possible seg fault when taking address space of a
 non-pointer value

---
 llvm/lib/Target/AMDGPU/AMDGPUAliasAnalysis.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAliasAnalysis.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAliasAnalysis.cpp
index 5a6868f96d970..d60dc22f1d837 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAliasAnalysis.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAliasAnalysis.cpp
@@ -49,8 +49,12 @@ void AMDGPUAAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
 AliasResult AMDGPUAAResult::alias(const MemoryLocation &LocA,
                                   const MemoryLocation &LocB, AAQueryInfo &AAQI,
                                   const Instruction *) {
-  unsigned asA = LocA.Ptr->getType()->getPointerAddressSpace();
-  unsigned asB = LocB.Ptr->getType()->getPointerAddressSpace();
+  Type *TypeA = LocA.Ptr->getType();
+  Type *TypeB = LocB.Ptr->getType();
+  if (!TypeA->isPointerTy() || !TypeB->isPointerTy())
+    return AliasResult::MayAlias;
+  unsigned asA = TypeA->getPointerAddressSpace();
+  unsigned asB = TypeB->getPointerAddressSpace();
 
   if (!AMDGPU::addrspacesMayAlias(asA, asB))
     return AliasResult::NoAlias;