llvm/test/Transforms/LoopVectorize/miniters.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --filter-out-after "vector.ph:" --version 5
; RUN: opt %s -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S | FileCheck %s
; RUN: opt %s -passes=loop-vectorize -force-vector-interleave=2 -force-vector-width=4 -S | FileCheck %s -check-prefix=UNROLL

target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"

@b = common global [1000 x i32] zeroinitializer, align 16
@c = common global [1000 x i32] zeroinitializer, align 16
@a = common global [1000 x i32] zeroinitializer, align 16

; Generate min.iters.check to skip the vector loop and jump to scalar.ph directly when loop iteration number is less than VF * UF.
define void @foo(i64 %N) {
; CHECK-LABEL: define void @foo(
; CHECK-SAME: i64 [[N:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    [[C:%.*]] = icmp sgt i64 [[N]], 0
; CHECK-NEXT:    br i1 [[C]], label %[[LOOP_PREHEADER:.*]], [[EXIT:label %.*]]
; CHECK:       [[LOOP_PREHEADER]]:
; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], [[SCALAR_PH:label %.*]], label %[[VECTOR_PH:.*]]
; CHECK:       [[VECTOR_PH]]:
;
; UNROLL-LABEL: define void @foo(
; UNROLL-SAME: i64 [[N:%.*]]) {
; UNROLL-NEXT:  [[ENTRY:.*:]]
; UNROLL-NEXT:    [[C:%.*]] = icmp sgt i64 [[N]], 0
; UNROLL-NEXT:    br i1 [[C]], label %[[LOOP_PREHEADER:.*]], [[EXIT:label %.*]]
; UNROLL:       [[LOOP_PREHEADER]]:
; UNROLL-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 8
; UNROLL-NEXT:    br i1 [[MIN_ITERS_CHECK]], [[SCALAR_PH:label %.*]], label %[[VECTOR_PH:.*]]
; UNROLL:       [[VECTOR_PH]]:
;
entry:
  %c = icmp sgt i64 %N, 0
  br i1 %c, label %loop, label %exit

loop:
  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
  %arrayidx = getelementptr inbounds [1000 x i32], ptr @b, i64 0, i64 %iv
  %tmp = load i32, ptr %arrayidx, align 4
  %arrayidx1 = getelementptr inbounds [1000 x i32], ptr @c, i64 0, i64 %iv
  %tmp1 = load i32, ptr %arrayidx1, align 4
  %add = add nsw i32 %tmp1, %tmp
  %arrayidx2 = getelementptr inbounds [1000 x i32], ptr @a, i64 0, i64 %iv
  store i32 %add, ptr %arrayidx2, 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
}

define void @min_iters_known_via_loop_guards_add(i32 %start, i32 %end, ptr %src) {
; CHECK-LABEL: define void @min_iters_known_via_loop_guards_add(
; CHECK-SAME: i32 [[START:%.*]], i32 [[END:%.*]], ptr [[SRC:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    [[SUB:%.*]] = sub i32 [[END]], [[START]]
; CHECK-NEXT:    [[PRE:%.*]] = icmp sgt i32 [[SUB]], 100
; CHECK-NEXT:    call void @llvm.assume(i1 [[PRE]])
; CHECK-NEXT:    [[ADD_1:%.*]] = add i32 [[SUB]], 1
; CHECK-NEXT:    [[IV_START:%.*]] = zext i32 [[ADD_1]] to i64
; CHECK-NEXT:    [[TMP0:%.*]] = sub i64 101, [[IV_START]]
; CHECK-NEXT:    br i1 false, [[SCALAR_PH:label %.*]], label %[[VECTOR_PH:.*]]
; CHECK:       [[VECTOR_PH]]:
;
; UNROLL-LABEL: define void @min_iters_known_via_loop_guards_add(
; UNROLL-SAME: i32 [[START:%.*]], i32 [[END:%.*]], ptr [[SRC:%.*]]) {
; UNROLL-NEXT:  [[ENTRY:.*:]]
; UNROLL-NEXT:    [[SUB:%.*]] = sub i32 [[END]], [[START]]
; UNROLL-NEXT:    [[PRE:%.*]] = icmp sgt i32 [[SUB]], 100
; UNROLL-NEXT:    call void @llvm.assume(i1 [[PRE]])
; UNROLL-NEXT:    [[ADD_1:%.*]] = add i32 [[SUB]], 1
; UNROLL-NEXT:    [[IV_START:%.*]] = zext i32 [[ADD_1]] to i64
; UNROLL-NEXT:    [[TMP0:%.*]] = sub i64 101, [[IV_START]]
; UNROLL-NEXT:    br i1 false, [[SCALAR_PH:label %.*]], label %[[VECTOR_PH:.*]]
; UNROLL:       [[VECTOR_PH]]:
;
entry:
  %sub = sub i32 %end, %start
  %pre = icmp sgt i32 %sub, 100
  call void @llvm.assume(i1 %pre)
  %add.1 = add i32 %sub, 1
  %iv.start = zext i32 %add.1 to i64
  br label %loop

loop:
  %iv = phi i64 [ %iv.start, %entry ], [ %iv.next, %loop ]
  %gep = getelementptr inbounds i64, ptr %src, i64 %iv
  store i64 %iv, ptr %gep
  %iv.next = add i64 %iv, 1
  %ec = icmp eq i64 %iv, 100
  br i1 %ec, label %exit, label %loop

exit:
  ret void
}