https://github.com/llvmbot updated https://github.com/llvm/llvm-project/pull/84950
>From b01c3dcf2eb5bdadd0df30e9ff5160f2da17293f Mon Sep 17 00:00:00 2001 From: Florian Hahn <f...@fhahn.com> Date: Thu, 7 Mar 2024 13:53:02 +0000 Subject: [PATCH 1/2] [LAA] Add test case for #82665. Test case for https://github.com/llvm/llvm-project/issues/82665. (cherry picked from commit 4cfd4a7896b5fd50274ec8573c259d7ad41741de) --- .../underlying-object-loop-varying-phi.ll | 175 ++++++++++++++++++ 1 file changed, 175 insertions(+) create mode 100644 llvm/test/Analysis/LoopAccessAnalysis/underlying-object-loop-varying-phi.ll diff --git a/llvm/test/Analysis/LoopAccessAnalysis/underlying-object-loop-varying-phi.ll b/llvm/test/Analysis/LoopAccessAnalysis/underlying-object-loop-varying-phi.ll new file mode 100644 index 00000000000000..1a5a6ac08d4045 --- /dev/null +++ b/llvm/test/Analysis/LoopAccessAnalysis/underlying-object-loop-varying-phi.ll @@ -0,0 +1,175 @@ +; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 4 +; RUN: opt -passes='print<access-info>' -disable-output %s 2>&1 | FileCheck %s + +target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128" + +; Test case for https://github.com/llvm/llvm-project/issues/82665. +define void @indirect_ptr_recurrences_read_write(ptr %A, ptr %B) { +; CHECK-LABEL: 'indirect_ptr_recurrences_read_write' +; CHECK-NEXT: loop: +; CHECK-NEXT: Memory dependences are safe +; 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: + br label %loop + +loop: + %iv = phi i64 [ 1, %entry ], [ %iv.next, %loop ] + %ptr.recur = phi ptr [ %A, %entry ], [ %ptr.next, %loop ] + %gep.B = getelementptr inbounds ptr, ptr %B, i64 %iv + %ptr.next = load ptr, ptr %gep.B, align 8, !tbaa !6 + %l = load i32, ptr %ptr.recur, align 4, !tbaa !10 + %xor = xor i32 %l, 1 + store i32 %xor, ptr %ptr.recur, align 4, !tbaa !10 + %iv.next = add nuw nsw i64 %iv, 1 + %ec = icmp eq i64 %iv.next, 5 + br i1 %ec, label %exit, label %loop + +exit: + ret void +} + +define i32 @indirect_ptr_recurrences_read_only_loop(ptr %A, ptr %B) { +; CHECK-LABEL: 'indirect_ptr_recurrences_read_only_loop' +; CHECK-NEXT: loop: +; CHECK-NEXT: Memory dependences are safe +; 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: + br label %loop + +loop: + %iv = phi i64 [ 1, %entry ], [ %iv.next, %loop ] + %ptr.recur = phi ptr [ %A, %entry ], [ %ptr.next, %loop ] + %red = phi i32 [ 0, %entry ], [ %xor, %loop ] + %gep.B = getelementptr inbounds ptr, ptr %B, i64 %iv + %ptr.next = load ptr, ptr %gep.B, align 8, !tbaa !6 + %l = load i32, ptr %ptr.recur, align 4, !tbaa !10 + %xor = xor i32 %l, 1 + %iv.next = add nuw nsw i64 %iv, 1 + %ec = icmp eq i64 %iv.next, 5 + br i1 %ec, label %exit, label %loop + +exit: + ret i32 %xor +} + +define void @indirect_ptr_recurrences_read_write_may_alias_no_tbaa(ptr %A, ptr %B) { +; CHECK-LABEL: 'indirect_ptr_recurrences_read_write_may_alias_no_tbaa' +; 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: + br label %loop + +loop: + %iv = phi i64 [ 1, %entry ], [ %iv.next, %loop ] + %ptr.recur = phi ptr [ %A, %entry ], [ %ptr.next, %loop ] + %gep.B = getelementptr inbounds ptr, ptr %B, i64 %iv + %ptr.next = load ptr, ptr %gep.B, align 8, !tbaa !6 + %l = load i32, ptr %ptr.recur, align 4 + %xor = xor i32 %l, 1 + store i32 %xor, ptr %ptr.recur, align 4 + %iv.next = add nuw nsw i64 %iv, 1 + %ec = icmp eq i64 %iv.next, 5 + br i1 %ec, label %exit, label %loop + +exit: + ret void +} + +define void @indirect_ptr_recurrences_read_write_may_alias_different_obj(ptr %A, ptr %B, ptr %C) { +; CHECK-LABEL: 'indirect_ptr_recurrences_read_write_may_alias_different_obj' +; 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: + br label %loop + +loop: + %iv = phi i64 [ 1, %entry ], [ %iv.next, %loop ] + %ptr.recur = phi ptr [ %A, %entry ], [ %ptr.next, %loop ] + %gep.B = getelementptr inbounds ptr, ptr %B, i64 %iv + %ptr.next = load ptr, ptr %gep.B, align 8, !tbaa !6 + %l = load i32, ptr %ptr.recur, align 4 + %xor = xor i32 %l, 1 + %gep.C = getelementptr inbounds ptr, ptr %C, i64 %iv + store i32 %xor, ptr %gep.C, align 4 + %iv.next = add nuw nsw i64 %iv, 1 + %ec = icmp eq i64 %iv.next, 5 + br i1 %ec, label %exit, label %loop + +exit: + ret void +} + +define void @indirect_ptr_recurrences_read_write_may_noalias_different_obj(ptr %A, ptr %B, ptr noalias %C) { +; CHECK-LABEL: 'indirect_ptr_recurrences_read_write_may_noalias_different_obj' +; CHECK-NEXT: loop: +; CHECK-NEXT: Memory dependences are safe +; 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: + br label %loop + +loop: + %iv = phi i64 [ 1, %entry ], [ %iv.next, %loop ] + %ptr.recur = phi ptr [ %A, %entry ], [ %ptr.next, %loop ] + %gep.B = getelementptr inbounds ptr, ptr %B, i64 %iv + %ptr.next = load ptr, ptr %gep.B, align 8, !tbaa !6 + %l = load i32, ptr %ptr.recur, align 4 + %xor = xor i32 %l, 1 + %gep.C = getelementptr inbounds ptr, ptr %C, i64 %iv + store i32 %xor, ptr %gep.C, align 4 + %iv.next = add nuw nsw i64 %iv, 1 + %ec = icmp eq i64 %iv.next, 5 + br i1 %ec, label %exit, label %loop + +exit: + ret void +} + + +!6 = !{!7, !7, i64 0} +!7 = !{!"any pointer", !8, i64 0} +!8 = !{!"omnipotent char", !9, i64 0} +!9 = !{!"Simple C/C++ TBAA"} +!10 = !{!11, !11, i64 0} +!11 = !{!"int", !8, i64 0} >From c7eb919d2cbef765e058c977b3ab0801b6a89b66 Mon Sep 17 00:00:00 2001 From: Florian Hahn <f...@fhahn.com> Date: Tue, 12 Mar 2024 08:55:03 +0000 Subject: [PATCH 2/2] [ValueTracking] Treat phi as underlying obj when not decomposing further (#84339) At the moment, getUnderlyingObjects simply continues for phis that do not refer to the same underlying object in loops, without adding them to the list of underlying objects, effectively ignoring those phis. Instead of ignoring those phis, add them to the list of underlying objects. This fixes a miscompile where LoopAccessAnalysis fails to identify a memory dependence, because no underlying objects can be found for a set of memory accesses. Fixes https://github.com/llvm/llvm-project/issues/82665. PR: https://github.com/llvm/llvm-project/pull/84339 (cherry picked from commit b274b23665dec30f3ae4fb83ccca8b77e6d3ada3) --- llvm/lib/Analysis/ValueTracking.cpp | 2 ++ .../underlying-object-loop-varying-phi.ll | 7 ++++++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 412115eb649c2f..9f9451e4e814ac 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -5986,6 +5986,8 @@ void llvm::getUnderlyingObjects(const Value *V, if (!LI || !LI->isLoopHeader(PN->getParent()) || isSameUnderlyingObjectInLoop(PN, LI)) append_range(Worklist, PN->incoming_values()); + else + Objects.push_back(P); continue; } diff --git a/llvm/test/Analysis/LoopAccessAnalysis/underlying-object-loop-varying-phi.ll b/llvm/test/Analysis/LoopAccessAnalysis/underlying-object-loop-varying-phi.ll index 1a5a6ac08d4045..106dc8c13a49fa 100644 --- a/llvm/test/Analysis/LoopAccessAnalysis/underlying-object-loop-varying-phi.ll +++ b/llvm/test/Analysis/LoopAccessAnalysis/underlying-object-loop-varying-phi.ll @@ -7,8 +7,13 @@ target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128" define void @indirect_ptr_recurrences_read_write(ptr %A, ptr %B) { ; CHECK-LABEL: 'indirect_ptr_recurrences_read_write' ; CHECK-NEXT: loop: -; CHECK-NEXT: Memory dependences are safe +; CHECK-NEXT: Report: unsafe dependent memory operations in loop. Use #pragma clang loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop +; CHECK-NEXT: Unsafe indirect dependence. ; CHECK-NEXT: Dependences: +; CHECK-NEXT: IndidrectUnsafe: +; CHECK-NEXT: %l = load i32, ptr %ptr.recur, align 4, !tbaa !4 -> +; CHECK-NEXT: store i32 %xor, ptr %ptr.recur, align 4, !tbaa !4 +; CHECK-EMPTY: ; CHECK-NEXT: Run-time memory checks: ; CHECK-NEXT: Grouped accesses: ; CHECK-EMPTY: _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
