llvm/test/Transforms/LoopVectorize/vector-loop-backedge-elimination-predicated-early-exit.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt -p loop-vectorize -S %s | FileCheck %s

; Test case for https://github.com/llvm/llvm-project/issues/193164.
define i64 @early_exit_predicated_single_iter(i1 %c) {
; CHECK-LABEL: define i64 @early_exit_predicated_single_iter(
; CHECK-SAME: i1 [[C:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
; CHECK:       [[VECTOR_PH]]:
; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i1> poison, i1 [[C]], i64 0
; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i1> [[BROADCAST_SPLATINSERT]], <2 x i1> poison, <2 x i32> zeroinitializer
; CHECK-NEXT:    [[TMP0:%.*]] = xor <2 x i1> [[BROADCAST_SPLAT]], splat (i1 true)
; CHECK-NEXT:    [[TMP1:%.*]] = freeze <2 x i1> [[TMP0]]
; CHECK-NEXT:    [[TMP2:%.*]] = call i1 @llvm.vector.reduce.or.v2i1(<2 x i1> [[TMP1]])
; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
; CHECK:       [[VECTOR_BODY]]:
; CHECK-NEXT:    br i1 [[TMP2]], label %[[VECTOR_EARLY_EXIT:.*]], label %[[VECTOR_BODY_INTERIM:.*]]
; CHECK:       [[VECTOR_BODY_INTERIM]]:
; CHECK-NEXT:    br label %[[MIDDLE_BLOCK:.*]]
; CHECK:       [[MIDDLE_BLOCK]]:
; CHECK-NEXT:    br label %[[EXIT:.*]]
; CHECK:       [[VECTOR_EARLY_EXIT]]:
; CHECK-NEXT:    [[TMP3:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v2i1(<2 x i1> [[TMP1]], i1 false)
; CHECK-NEXT:    br label %[[EARLY_EXIT:.*]]
; CHECK:       [[EARLY_EXIT]]:
; CHECK-NEXT:    ret i64 [[TMP3]]
; CHECK:       [[EXIT]]:
; CHECK-NEXT:    ret i64 0
;
entry:
  br label %loop

loop:
  %iv = phi i64 [ 0, %entry ], [ %iv.next, %latch ]
  br i1 %c, label %latch, label %early.exit

early.exit:
  %iv.lcssa = phi i64 [ %iv, %loop ]
  ret i64 %iv.lcssa

latch:
  %iv.next = add i64 %iv, 1
  %cmp = icmp eq i64 %iv, 0
  br i1 %cmp, label %loop, label %exit, !llvm.loop !0

exit:
  ret i64 0
}

!0 = distinct !{!0, !1, !2, !3}
!1 = !{!"llvm.loop.mustprogress"}
!2 = !{!"llvm.loop.vectorize.predicate.enable"}
!3 = !{!"llvm.loop.vectorize.enable"}