https://github.com/fhahn created https://github.com/llvm/llvm-project/pull/129317
Backport 275baedfde9dcd344bc4f11f552b046a69a4bf3f 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 >From 9bd248a009768ac140516f744f2a257e38660d99 Mon Sep 17 00:00:00 2001 From: Florian Hahn <f...@fhahn.com> Date: Fri, 28 Feb 2025 20:56:12 +0000 Subject: [PATCH] [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 --- llvm/lib/Analysis/LoopAccessAnalysis.cpp | 12 ++++-- ...erlying-object-different-address-spaces.ll | 39 +++++++++++++++++++ 2 files changed, 47 insertions(+), 4 deletions(-) create mode 100644 llvm/test/Analysis/LoopAccessAnalysis/underlying-object-different-address-spaces.ll diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp index 697b40403902c..dcd8a910d0f49 100644 --- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp +++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp @@ -1283,8 +1283,10 @@ 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. @@ -1364,12 +1366,14 @@ void AccessAnalysis::processMemAccesses() { UnderlyingObj->getType()->getPointerAddressSpace())) continue; + unsigned AccessAS = cast<PointerType>(Ptr->getType())->getAddressSpace(); UnderlyingObjToAccessMap::iterator Prev = - ObjToLastAccess.find(UnderlyingObj); + ObjToLastAccess.find({UnderlyingObj,AccessAS + }); if (Prev != ObjToLastAccess.end()) DepCands.unionSets(Access, Prev->second); - ObjToLastAccess[UnderlyingObj] = Access; + ObjToLastAccess[{UnderlyingObj, AccessAS}] = Access; LLVM_DEBUG(dbgs() << " " << *UnderlyingObj << "\n"); } } diff --git a/llvm/test/Analysis/LoopAccessAnalysis/underlying-object-different-address-spaces.ll b/llvm/test/Analysis/LoopAccessAnalysis/underlying-object-different-address-spaces.ll new file mode 100644 index 0000000000000..adf73c091be00 --- /dev/null +++ b/llvm/test/Analysis/LoopAccessAnalysis/underlying-object-different-address-spaces.ll @@ -0,0 +1,39 @@ +; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5 +; RUN: opt -passes='print<access-info>' -disable-output %s 2>&1 | FileCheck %s + +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" + +; Test case for https://github.com/llvm/llvm-project/issues/124759. The same +; underlying object is access through pointers with different address spaces. +define void @same_underlying_object_different_address_spaces(ptr %dst1.as1, ptr %dst2.as1) { +; CHECK-LABEL: 'same_underlying_object_different_address_spaces' +; CHECK-NEXT: loop: +; CHECK-NEXT: Report: cannot identify array bounds +; CHECK-NEXT: Dependences: +; CHECK-NEXT: Run-time memory checks: +; CHECK-NEXT: Grouped accesses: +; CHECK-EMPTY: +; CHECK-NEXT: Non vectorizable stores to invariant address were not found in loop. +; CHECK-NEXT: SCEV assumptions: +; CHECK-EMPTY: +; CHECK-NEXT: Expressions re-written: +; +entry: + %alloc = alloca i8, i64 0, align 128 + %as3 = addrspacecast ptr %alloc to ptr addrspace(3) + %as4 = addrspacecast ptr %alloc to ptr addrspace(4) + br label %loop + +loop: + %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ] + store i32 0, ptr addrspace(4) %as4, align 4 + store i32 0, ptr %dst1.as1, align 4 + %l = load i64, ptr addrspace(3) %as3, align 4 + store i64 %l, ptr %dst2.as1, align 4 + %iv.next = add i64 %iv, 1 + %c = icmp eq i64 %iv.next, 100 + br i1 %c, label %loop, label %exit + +exit: + ret void +} _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
