; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -passes=loop-vectorize -prefer-predicate-over-epilogue=predicate-else-scalar-epilogue < %s | FileCheck %s
; RUN: opt -S -passes=loop-vectorize < %s | FileCheck %s

; This tests should produce the same result as with default options, and when tail folding
; is preferred, because the vectorizer can't fold the tail by masking (due to an
; outside user of %incdec.ptr in %end) and should fallback to a scalar epilogue.
;
; The first test (@basic_loop) simply relies on the command-line switches.
; The second test (@metadata) specificies its tail-folding preference via metadata.
; Both tests should always generate a scalar epilogue.

target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"

define void @basic_loop(ptr nocapture readonly %ptr, i32 %size, ptr %pos) {
; CHECK-LABEL: @basic_loop(
; CHECK-NEXT:  header:
; CHECK-NEXT:    [[PTR0:%.*]] = load ptr, ptr [[POS:%.*]], align 4
; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i32 [[SIZE:%.*]], 4
; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
; CHECK:       vector.ph:
; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i32 [[SIZE]], 4
; CHECK-NEXT:    [[N_VEC:%.*]] = sub i32 [[SIZE]], [[N_MOD_VF]]
; CHECK-NEXT:    [[IND_END:%.*]] = sub i32 [[SIZE]], [[N_VEC]]
; CHECK-NEXT:    [[IND_END1:%.*]] = getelementptr i8, ptr [[PTR:%.*]], i32 [[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:    [[TMP0:%.*]] = add i32 [[INDEX]], 0
; CHECK-NEXT:    [[NEXT_GEP:%.*]] = getelementptr i8, ptr [[PTR]], i32 [[TMP0]]
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[NEXT_GEP]], i32 1
; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[TMP1]], i32 0
; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP2]], align 1
; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr i8, ptr [[NEXT_GEP]], i32 0
; CHECK-NEXT:    store <4 x i8> [[WIDE_LOAD]], ptr [[TMP3]], align 1
; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 4
; CHECK-NEXT:    [[TMP4:%.*]] = icmp eq i32 [[INDEX_NEXT]], [[N_VEC]]
; CHECK-NEXT:    br i1 [[TMP4]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
; CHECK:       middle.block:
; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i32 [[SIZE]], [[N_VEC]]
; CHECK-NEXT:    br i1 [[CMP_N]], label [[END:%.*]], label [[SCALAR_PH]]
; CHECK:       scalar.ph:
; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i32 [ [[IND_END]], [[MIDDLE_BLOCK]] ], [ [[SIZE]], [[HEADER:%.*]] ]
; CHECK-NEXT:    [[BC_RESUME_VAL2:%.*]] = phi ptr [ [[IND_END1]], [[MIDDLE_BLOCK]] ], [ [[PTR]], [[HEADER]] ]
; CHECK-NEXT:    br label [[BODY:%.*]]
; CHECK:       body:
; CHECK-NEXT:    [[DEC66:%.*]] = phi i32 [ [[DEC:%.*]], [[BODY]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
; CHECK-NEXT:    [[BUFF:%.*]] = phi ptr [ [[INCDEC_PTR:%.*]], [[BODY]] ], [ [[BC_RESUME_VAL2]], [[SCALAR_PH]] ]
; CHECK-NEXT:    [[INCDEC_PTR]] = getelementptr inbounds i8, ptr [[BUFF]], i32 1
; CHECK-NEXT:    [[DEC]] = add nsw i32 [[DEC66]], -1
; CHECK-NEXT:    [[TMP5:%.*]] = load i8, ptr [[INCDEC_PTR]], align 1
; CHECK-NEXT:    store i8 [[TMP5]], ptr [[BUFF]], align 1
; CHECK-NEXT:    [[TOBOOL11:%.*]] = icmp eq i32 [[DEC]], 0
; CHECK-NEXT:    br i1 [[TOBOOL11]], label [[END]], label [[BODY]], !llvm.loop [[LOOP2:![0-9]+]]
; CHECK:       end:
; CHECK-NEXT:    [[INCDEC_PTR_LCSSA:%.*]] = phi ptr [ [[INCDEC_PTR]], [[BODY]] ], [ [[IND_END1]], [[MIDDLE_BLOCK]] ]
; CHECK-NEXT:    store ptr [[INCDEC_PTR_LCSSA]], ptr [[POS]], align 4
; CHECK-NEXT:    ret void
;
header:
  %ptr0 = load ptr, ptr %pos, align 4
  br label %body

body:
  %dec66 = phi i32 [ %dec, %body ], [ %size, %header ]
  %buff = phi ptr [ %incdec.ptr, %body ], [ %ptr, %header ]
  %incdec.ptr = getelementptr inbounds i8, ptr %buff, i32 1
  %dec = add nsw i32 %dec66, -1
  %0 = load i8, ptr %incdec.ptr, align 1
  store i8 %0, ptr %buff, align 1
  %tobool11 = icmp eq i32 %dec, 0
  br i1 %tobool11, label %end, label %body

end:
  store ptr %incdec.ptr, ptr %pos, align 4
  ret void
}

define void @metadata(ptr nocapture readonly %ptr, i32 %size, ptr %pos) {
; CHECK-LABEL: @metadata(
; CHECK-NEXT:  header:
; CHECK-NEXT:    [[PTR0:%.*]] = load ptr, ptr [[POS:%.*]], align 4
; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i32 [[SIZE:%.*]], 4
; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
; CHECK:       vector.ph:
; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i32 [[SIZE]], 4
; CHECK-NEXT:    [[N_VEC:%.*]] = sub i32 [[SIZE]], [[N_MOD_VF]]
; CHECK-NEXT:    [[IND_END:%.*]] = sub i32 [[SIZE]], [[N_VEC]]
; CHECK-NEXT:    [[IND_END1:%.*]] = getelementptr i8, ptr [[PTR:%.*]], i32 [[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:    [[TMP0:%.*]] = add i32 [[INDEX]], 0
; CHECK-NEXT:    [[NEXT_GEP:%.*]] = getelementptr i8, ptr [[PTR]], i32 [[TMP0]]
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[NEXT_GEP]], i32 1
; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[TMP1]], i32 0
; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP2]], align 1
; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr i8, ptr [[NEXT_GEP]], i32 0
; CHECK-NEXT:    store <4 x i8> [[WIDE_LOAD]], ptr [[TMP3]], align 1
; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 4
; CHECK-NEXT:    [[TMP4:%.*]] = icmp eq i32 [[INDEX_NEXT]], [[N_VEC]]
; CHECK-NEXT:    br i1 [[TMP4]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
; CHECK:       middle.block:
; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i32 [[SIZE]], [[N_VEC]]
; CHECK-NEXT:    br i1 [[CMP_N]], label [[END:%.*]], label [[SCALAR_PH]]
; CHECK:       scalar.ph:
; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i32 [ [[IND_END]], [[MIDDLE_BLOCK]] ], [ [[SIZE]], [[HEADER:%.*]] ]
; CHECK-NEXT:    [[BC_RESUME_VAL2:%.*]] = phi ptr [ [[IND_END1]], [[MIDDLE_BLOCK]] ], [ [[PTR]], [[HEADER]] ]
; CHECK-NEXT:    br label [[BODY:%.*]]
; CHECK:       body:
; CHECK-NEXT:    [[DEC66:%.*]] = phi i32 [ [[DEC:%.*]], [[BODY]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
; CHECK-NEXT:    [[BUFF:%.*]] = phi ptr [ [[INCDEC_PTR:%.*]], [[BODY]] ], [ [[BC_RESUME_VAL2]], [[SCALAR_PH]] ]
; CHECK-NEXT:    [[INCDEC_PTR]] = getelementptr inbounds i8, ptr [[BUFF]], i32 1
; CHECK-NEXT:    [[DEC]] = add nsw i32 [[DEC66]], -1
; CHECK-NEXT:    [[TMP5:%.*]] = load i8, ptr [[INCDEC_PTR]], align 1
; CHECK-NEXT:    store i8 [[TMP5]], ptr [[BUFF]], align 1
; CHECK-NEXT:    [[TOBOOL11:%.*]] = icmp eq i32 [[DEC]], 0
; CHECK-NEXT:    br i1 [[TOBOOL11]], label [[END]], label [[BODY]], !llvm.loop [[LOOP5:![0-9]+]]
; CHECK:       end:
; CHECK-NEXT:    [[INCDEC_PTR_LCSSA:%.*]] = phi ptr [ [[INCDEC_PTR]], [[BODY]] ], [ [[IND_END1]], [[MIDDLE_BLOCK]] ]
; CHECK-NEXT:    store ptr [[INCDEC_PTR_LCSSA]], ptr [[POS]], align 4
; CHECK-NEXT:    ret void
;
header:
  %ptr0 = load ptr, ptr %pos, align 4
  br label %body

body:
  %dec66 = phi i32 [ %dec, %body ], [ %size, %header ]
  %buff = phi ptr [ %incdec.ptr, %body ], [ %ptr, %header ]
  %incdec.ptr = getelementptr inbounds i8, ptr %buff, i32 1
  %dec = add nsw i32 %dec66, -1
  %0 = load i8, ptr %incdec.ptr, align 1
  store i8 %0, ptr %buff, align 1
  %tobool11 = icmp eq i32 %dec, 0
  br i1 %tobool11, label %end, label %body, !llvm.loop !1

end:
  store ptr %incdec.ptr, ptr %pos, align 4
  ret void
}

!1 = distinct !{!1, !2, !3}
!2 = !{!"llvm.loop.vectorize.predicate.enable", i1 true}
!3 = !{!"llvm.loop.vectorize.enable", i1 true}