llvm/test/Analysis/LoopAccessAnalysis/load-store-index-loaded-in-loop.ll

; 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

; Test case for https://github.com/llvm/llvm-project/issues/87189.
; It is not safe to vectorize because %indices are loaded in the loop and the
; same indices could be loaded in later iterations.
; FIXME: currently this is incorrectly considered safe for vectorization with
; runtime checks
define void @B_indices_loaded_in_loop_A_stored(ptr %A, ptr noalias %B, i64 %N, i64 %off) {
; CHECK-LABEL: 'B_indices_loaded_in_loop_A_stored'
; 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:        IndirectUnsafe:
; CHECK-NEXT:            %l = load i32, ptr %gep.B, align 4 ->
; CHECK-NEXT:            store i32 %inc, ptr %gep.B, align 4
; CHECK-EMPTY:
; CHECK-NEXT:        Unknown:
; CHECK-NEXT:            %indices = load i8, ptr %gep.A, align 1 ->
; CHECK-NEXT:            store i32 %l, ptr %gep.C, align 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 [ 0, %entry ], [ %iv.next, %loop ]
  %iv.off = add nuw nsw i64 %iv, %off
  %gep.A = getelementptr inbounds i8, ptr %A, i64 %iv.off
  %indices = load i8, ptr %gep.A, align 1
  %indices.ext = zext i8 %indices to i64
  %gep.B = getelementptr inbounds i32, ptr %B, i64 %indices.ext
  %l = load i32, ptr %gep.B, align 4
  %inc = add i32 %l, 1
  store i32 %inc, ptr %gep.B, align 4
  %gep.C = getelementptr inbounds i32, ptr %A, i64 %iv
  store i32 %l, ptr %gep.C, align 4
  %iv.next = add nuw nsw i64 %iv, 1
  %ec = icmp eq i64 %iv.next, %N
  br i1 %ec, label %exit, label %loop

exit:
  ret void
}

; It is not safe to vectorize because %indices are loaded in the loop and the
; same indices could be loaded in later iterations.
define void @B_indices_loaded_in_loop_A_not_stored(ptr %A, ptr noalias %B, i64 %N) {
; CHECK-LABEL: 'B_indices_loaded_in_loop_A_not_stored'
; 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:        IndirectUnsafe:
; CHECK-NEXT:            %l = load i32, ptr %gep.B, align 4 ->
; CHECK-NEXT:            store i32 %inc, ptr %gep.B, align 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 [ 0, %entry ], [ %iv.next, %loop ]
  %gep.A = getelementptr inbounds i8, ptr %A, i64 %iv
  %indices = load i8, ptr %gep.A, align 1
  %indices.ext = zext i8 %indices to i64
  %gep.B = getelementptr inbounds i32, ptr %B, i64 %indices.ext
  %l = load i32, ptr %gep.B, align 4
  %inc = add i32 %l, 1
  store i32 %inc, ptr %gep.B, align 4
  %iv.next = add nuw nsw i64 %iv, 1
  %ec = icmp eq i64 %iv.next, %N
  br i1 %ec, label %exit, label %loop

exit:
  ret void
}