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release/18.x: [ValueTracking] Treat phi as underlying obj when not decomposing further (#84339) #84950

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Merged
merged 2 commits into from
Mar 13, 2024
Merged

release/18.x: [ValueTracking] Treat phi as underlying obj when not decomposing further (#84339) #84950

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b01c3dc
[LAA] Add test case for #82665.
fhahn Mar 7, 2024
c7eb919
[ValueTracking] Treat phi as underlying obj when not decomposing furt…
fhahn Mar 12, 2024
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2 changes: 2 additions & 0 deletions llvm/lib/Analysis/ValueTracking.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

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180 changes: 180 additions & 0 deletions llvm/test/Analysis/LoopAccessAnalysis/underlying-object-loop-varying-phi.ll
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@@ -0,0 +1,180 @@
; 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: 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:
; 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}