; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --filter-out-after "^scalar.ph" --version 6
; RUN: opt -S -passes=loop-vectorize -force-vector-width=2 < %s | FileCheck %s

target triple = "i386-unknown-linux-gnu"

; Make sure we don't assert when creating GEPs with negative index.

define void @test(ptr %dest, i32 %n) "target-cpu"="pentium4" {
; CHECK-LABEL: define void @test(
; CHECK-SAME: ptr [[DEST:%.*]], i32 [[N:%.*]]) #[[ATTR0:[0-9]+]] {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[N]], 1
; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i32 [[TMP0]], 4
; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
; CHECK:       [[VECTOR_PH]]:
; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i32 [[TMP0]], 4
; CHECK-NEXT:    [[N_VEC:%.*]] = sub i32 [[TMP0]], [[N_MOD_VF]]
; CHECK-NEXT:    [[TMP1:%.*]] = sub i32 [[N]], [[N_VEC]]
; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
; CHECK:       [[VECTOR_BODY]]:
; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = sub i32 [[N]], [[INDEX]]
; CHECK-NEXT:    [[TMP2:%.*]] = add i32 [[OFFSET_IDX]], -1
; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr i8, ptr [[DEST]], i32 [[TMP2]]
; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i8, ptr [[TMP3]], i32 0
; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr i8, ptr [[TMP4]], i32 -1
; CHECK-NEXT:    [[TMP6:%.*]] = getelementptr i8, ptr [[TMP3]], i32 -2
; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr i8, ptr [[TMP6]], i32 -1
; CHECK-NEXT:    store <2 x i8> zeroinitializer, ptr [[TMP5]], align 1
; CHECK-NEXT:    store <2 x i8> zeroinitializer, ptr [[TMP7]], align 1
; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 4
; CHECK-NEXT:    [[TMP8:%.*]] = icmp eq i32 [[INDEX_NEXT]], [[N_VEC]]
; CHECK-NEXT:    br i1 [[TMP8]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
; CHECK:       [[MIDDLE_BLOCK]]:
; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i32 [[TMP0]], [[N_VEC]]
; CHECK-NEXT:    br i1 [[CMP_N]], [[EXIT:label %.*]], label %[[SCALAR_PH]]
; CHECK:       [[SCALAR_PH]]:
;
entry:
  br label %loop

loop:
  %iv = phi i32 [ %iv.next, %loop ], [ %n, %entry ]
  %iv.next = add i32 %iv, -1
  %gep = getelementptr i8, ptr %dest, i32 %iv.next
  store i8 0, ptr %gep, align 1
  %cmp = icmp eq i32 %iv, 0
  br i1 %cmp, label %exit, label %loop

exit:
  ret void
}