[LAA] Consider accessed addrspace when mapping underlying obj to access. (#129087)

In some cases, it is possible for the same underlying object to be
accessed via pointers to different address spaces. This could lead to
pointers from different address spaces ending up in the same dependency
set, which isn't allowed (and triggers an assertion).

Update the mapping from underlying object -> last access to also include
the accessing address space.

Fixes https://github.com/llvm/llvm-project/issues/124759.

PR: https://github.com/llvm/llvm-project/pull/129087

1 files changed, 8 insertions, 4 deletions

diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index cf3bb6a..38ee82b 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -1362,8 +1362,10 @@ void AccessAnalysis::processMemAccesses() {
 
     bool SetHasWrite = false;
 
-    // Map of pointers to last access encountered.
-    typedef DenseMap<const Value*, MemAccessInfo> UnderlyingObjToAccessMap;
+    // Map of (pointer to underlying objects, accessed address space) to last
+    // access encountered.
+    typedef DenseMap<std::pair<const Value *, unsigned>, MemAccessInfo>
+        UnderlyingObjToAccessMap;
     UnderlyingObjToAccessMap ObjToLastAccess;
 
     // Set of access to check after all writes have been processed.
@@ -1443,8 +1445,10 @@ void AccessAnalysis::processMemAccesses() {
                     UnderlyingObj->getType()->getPointerAddressSpace()))
               continue;
 
-            auto [It, Inserted] =
-                ObjToLastAccess.try_emplace(UnderlyingObj, Access);
+            auto [It, Inserted] = ObjToLastAccess.try_emplace(
+                {UnderlyingObj,
+                 cast<PointerType>(Ptr->getType())->getAddressSpace()},
+                Access);
             if (!Inserted) {
               DepCands.unionSets(Access, It->second);
               It->second = Access;