llvm/test/Transforms/LoopVectorize/find-last.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -passes=loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -S %s | FileCheck %s
; RUN: opt -passes=loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -prefer-inloop-reductions -S %s | FileCheck %s

; Test vectorization of a "find last" pattern where a scalar value is
; conditionally updated based on comparing elements from two arrays.
define i32 @find_last_with_select(ptr noalias %a, ptr noalias %b) {
; CHECK-LABEL: @find_last_with_select(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[VECTOR_PH:%.*]]
; CHECK:       vector.ph:
; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
; CHECK:       vector.body:
; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 1), [[VECTOR_PH]] ], [ [[TMP7:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[TMP0:%.*]] = phi <4 x i1> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP6:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i64 [[INDEX]]
; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP1]], align 4
; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[B:%.*]], i64 [[INDEX]]
; CHECK-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i32>, ptr [[TMP2]], align 4
; CHECK-NEXT:    [[TMP3:%.*]] = icmp sge <4 x i32> [[WIDE_LOAD]], [[WIDE_LOAD1]]
; CHECK-NEXT:    [[TMP4:%.*]] = freeze <4 x i1> [[TMP3]]
; CHECK-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
; CHECK-NEXT:    [[TMP6]] = select i1 [[TMP5]], <4 x i1> [[TMP3]], <4 x i1> [[TMP0]]
; CHECK-NEXT:    [[TMP7]] = select i1 [[TMP5]], <4 x i32> [[WIDE_LOAD]], <4 x i32> [[VEC_PHI]]
; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
; CHECK-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], 500
; CHECK-NEXT:    br i1 [[TMP8]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
; CHECK:       middle.block:
; CHECK-NEXT:    [[TMP9:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP7]], <4 x i1> [[TMP6]], i32 1)
; CHECK-NEXT:    br label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    ret i32 [[TMP9]]
;
entry:
  br label %loop

loop:
  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
  %rdx = phi i32 [ 1, %entry ], [ %sel, %loop ]
  %gep.a = getelementptr inbounds i32, ptr %a, i64 %iv
  %load.a = load i32, ptr %gep.a, align 4
  %gep.b = getelementptr inbounds i32, ptr %b, i64 %iv
  %load.b = load i32, ptr %gep.b, align 4
  %cmp = icmp slt i32 %load.a, %load.b
  %sel = select i1 %cmp, i32 %rdx, i32 %load.a
  %iv.next = add nuw nsw i64 %iv, 1
  %exitcond = icmp eq i64 %iv.next, 500
  br i1 %exitcond, label %exit, label %loop

exit:
  ret i32 %sel
}

; Keep when a[i] > b[i] (signed), i.e., update when a[i] <= b[i].
define i32 @find_last_sgt_inverted(ptr noalias %a, ptr noalias %b) {
; CHECK-LABEL: @find_last_sgt_inverted(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[VECTOR_PH:%.*]]
; CHECK:       vector.ph:
; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
; CHECK:       vector.body:
; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 1), [[VECTOR_PH]] ], [ [[TMP7:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[TMP0:%.*]] = phi <4 x i1> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP6:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i64 [[INDEX]]
; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP1]], align 4
; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[B:%.*]], i64 [[INDEX]]
; CHECK-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i32>, ptr [[TMP2]], align 4
; CHECK-NEXT:    [[TMP3:%.*]] = icmp sle <4 x i32> [[WIDE_LOAD]], [[WIDE_LOAD1]]
; CHECK-NEXT:    [[TMP4:%.*]] = freeze <4 x i1> [[TMP3]]
; CHECK-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
; CHECK-NEXT:    [[TMP6]] = select i1 [[TMP5]], <4 x i1> [[TMP3]], <4 x i1> [[TMP0]]
; CHECK-NEXT:    [[TMP7]] = select i1 [[TMP5]], <4 x i32> [[WIDE_LOAD]], <4 x i32> [[VEC_PHI]]
; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
; CHECK-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], 500
; CHECK-NEXT:    br i1 [[TMP8]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
; CHECK:       middle.block:
; CHECK-NEXT:    [[TMP9:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP7]], <4 x i1> [[TMP6]], i32 1)
; CHECK-NEXT:    br label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    ret i32 [[TMP9]]
;
entry:
  br label %loop

loop:
  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
  %rdx = phi i32 [ 1, %entry ], [ %sel, %loop ]
  %gep.a = getelementptr inbounds i32, ptr %a, i64 %iv
  %load.a = load i32, ptr %gep.a, align 4
  %gep.b = getelementptr inbounds i32, ptr %b, i64 %iv
  %load.b = load i32, ptr %gep.b, align 4
  %cmp = icmp sgt i32 %load.a, %load.b
  %sel = select i1 %cmp, i32 %rdx, i32 %load.a
  %iv.next = add nuw nsw i64 %iv, 1
  %exitcond = icmp eq i64 %iv.next, 500
  br i1 %exitcond, label %exit, label %loop

exit:
  ret i32 %sel
}

; Keep when a[i] < b[i] (unsigned), i.e., update when a[i] >= b[i].
define i32 @find_last_ult_inverted(ptr noalias %a, ptr noalias %b) {
; CHECK-LABEL: @find_last_ult_inverted(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[VECTOR_PH:%.*]]
; CHECK:       vector.ph:
; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
; CHECK:       vector.body:
; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 1), [[VECTOR_PH]] ], [ [[TMP7:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[TMP0:%.*]] = phi <4 x i1> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP6:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i64 [[INDEX]]
; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP1]], align 4
; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[B:%.*]], i64 [[INDEX]]
; CHECK-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i32>, ptr [[TMP2]], align 4
; CHECK-NEXT:    [[TMP3:%.*]] = icmp uge <4 x i32> [[WIDE_LOAD]], [[WIDE_LOAD1]]
; CHECK-NEXT:    [[TMP4:%.*]] = freeze <4 x i1> [[TMP3]]
; CHECK-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
; CHECK-NEXT:    [[TMP6]] = select i1 [[TMP5]], <4 x i1> [[TMP3]], <4 x i1> [[TMP0]]
; CHECK-NEXT:    [[TMP7]] = select i1 [[TMP5]], <4 x i32> [[WIDE_LOAD]], <4 x i32> [[VEC_PHI]]
; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
; CHECK-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], 500
; CHECK-NEXT:    br i1 [[TMP8]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
; CHECK:       middle.block:
; CHECK-NEXT:    [[TMP9:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP7]], <4 x i1> [[TMP6]], i32 1)
; CHECK-NEXT:    br label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    ret i32 [[TMP9]]
;
entry:
  br label %loop

loop:
  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
  %rdx = phi i32 [ 1, %entry ], [ %sel, %loop ]
  %gep.a = getelementptr inbounds i32, ptr %a, i64 %iv
  %load.a = load i32, ptr %gep.a, align 4
  %gep.b = getelementptr inbounds i32, ptr %b, i64 %iv
  %load.b = load i32, ptr %gep.b, align 4
  %cmp = icmp ult i32 %load.a, %load.b
  %sel = select i1 %cmp, i32 %rdx, i32 %load.a
  %iv.next = add nuw nsw i64 %iv, 1
  %exitcond = icmp eq i64 %iv.next, 500
  br i1 %exitcond, label %exit, label %loop

exit:
  ret i32 %sel
}

; Keep when a[i] != b[i], i.e., update when a[i] == b[i].
define i32 @find_last_ne_inverted(ptr noalias %a, ptr noalias %b) {
; CHECK-LABEL: @find_last_ne_inverted(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[VECTOR_PH:%.*]]
; CHECK:       vector.ph:
; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
; CHECK:       vector.body:
; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 1), [[VECTOR_PH]] ], [ [[TMP7:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[TMP0:%.*]] = phi <4 x i1> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP6:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i64 [[INDEX]]
; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP1]], align 4
; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[B:%.*]], i64 [[INDEX]]
; CHECK-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i32>, ptr [[TMP2]], align 4
; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq <4 x i32> [[WIDE_LOAD]], [[WIDE_LOAD1]]
; CHECK-NEXT:    [[TMP4:%.*]] = freeze <4 x i1> [[TMP3]]
; CHECK-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
; CHECK-NEXT:    [[TMP6]] = select i1 [[TMP5]], <4 x i1> [[TMP3]], <4 x i1> [[TMP0]]
; CHECK-NEXT:    [[TMP7]] = select i1 [[TMP5]], <4 x i32> [[WIDE_LOAD]], <4 x i32> [[VEC_PHI]]
; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
; CHECK-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], 500
; CHECK-NEXT:    br i1 [[TMP8]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
; CHECK:       middle.block:
; CHECK-NEXT:    [[TMP9:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP7]], <4 x i1> [[TMP6]], i32 1)
; CHECK-NEXT:    br label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    ret i32 [[TMP9]]
;
entry:
  br label %loop

loop:
  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
  %rdx = phi i32 [ 1, %entry ], [ %sel, %loop ]
  %gep.a = getelementptr inbounds i32, ptr %a, i64 %iv
  %load.a = load i32, ptr %gep.a, align 4
  %gep.b = getelementptr inbounds i32, ptr %b, i64 %iv
  %load.b = load i32, ptr %gep.b, align 4
  %cmp = icmp ne i32 %load.a, %load.b
  %sel = select i1 %cmp, i32 %rdx, i32 %load.a
  %iv.next = add nuw nsw i64 %iv, 1
  %exitcond = icmp eq i64 %iv.next, 500
  br i1 %exitcond, label %exit, label %loop

exit:
  ret i32 %sel
}

define i32 @loop_inv_select_condition_issue_182152(i32 %iv.start, i32 %a, i32 %b) {
; CHECK-LABEL: @loop_inv_select_condition_issue_182152(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[INV_COND:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT:    [[SMAX:%.*]] = call i32 @llvm.smax.i32(i32 [[IV_START:%.*]], i32 1)
; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[SMAX]], 1
; CHECK-NEXT:    [[TMP1:%.*]] = sub i32 [[TMP0]], [[IV_START]]
; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i32 [[TMP1]], 4
; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
; CHECK:       vector.ph:
; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i32 [[TMP1]], 4
; CHECK-NEXT:    [[N_VEC:%.*]] = sub i32 [[TMP1]], [[N_MOD_VF]]
; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i1> poison, i1 [[INV_COND]], i64 0
; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i1> [[BROADCAST_SPLATINSERT]], <4 x i1> poison, <4 x i32> zeroinitializer
; CHECK-NEXT:    [[TMP2:%.*]] = add i32 [[IV_START]], [[N_VEC]]
; CHECK-NEXT:    [[TMP3:%.*]] = xor <4 x i1> [[BROADCAST_SPLAT]], splat (i1 true)
; CHECK-NEXT:    [[TMP4:%.*]] = freeze <4 x i1> [[TMP3]]
; CHECK-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
; CHECK-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <4 x i32> poison, i32 [[IV_START]], i64 0
; CHECK-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT1]], <4 x i32> poison, <4 x i32> zeroinitializer
; CHECK-NEXT:    [[INDUCTION:%.*]] = add <4 x i32> [[BROADCAST_SPLAT2]], <i32 0, i32 1, i32 2, i32 3>
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       vector.body:
; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[LOOP]] ]
; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ [[INDUCTION]], [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[LOOP]] ]
; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP8:%.*]], [[LOOP]] ]
; CHECK-NEXT:    [[TMP6:%.*]] = phi <4 x i1> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP7:%.*]], [[LOOP]] ]
; CHECK-NEXT:    [[TMP7]] = select i1 [[TMP5]], <4 x i1> [[TMP3]], <4 x i1> [[TMP6]]
; CHECK-NEXT:    [[TMP8]] = select i1 [[TMP5]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 4
; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
; CHECK-NEXT:    [[TMP9:%.*]] = icmp eq i32 [[INDEX_NEXT]], [[N_VEC]]
; CHECK-NEXT:    br i1 [[TMP9]], label [[MIDDLE_BLOCK:%.*]], label [[LOOP]], !llvm.loop [[LOOP6:![0-9]+]]
; CHECK:       middle.block:
; CHECK-NEXT:    [[TMP10:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP8]], <4 x i1> [[TMP7]], i32 0)
; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i32 [[TMP1]], [[N_VEC]]
; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[SCALAR_PH]]
; CHECK:       scalar.ph:
; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i32 [ [[TMP2]], [[MIDDLE_BLOCK]] ], [ [[IV_START]], [[ENTRY:%.*]] ]
; CHECK-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP10]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ]
; CHECK-NEXT:    br label [[LOOP1:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[LOOP1]] ]
; CHECK-NEXT:    [[RDX:%.*]] = phi i32 [ [[BC_MERGE_RDX]], [[SCALAR_PH]] ], [ [[SELECT:%.*]], [[LOOP1]] ]
; CHECK-NEXT:    [[SELECT]] = select i1 [[INV_COND]], i32 [[RDX]], i32 [[IV]]
; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], 1
; CHECK-NEXT:    [[EXIT_COND:%.*]] = icmp sgt i32 [[IV]], 0
; CHECK-NEXT:    br i1 [[EXIT_COND]], label [[EXIT]], label [[LOOP1]], !llvm.loop [[LOOP7:![0-9]+]]
; CHECK:       exit:
; CHECK-NEXT:    [[SELECT_LCSSA:%.*]] = phi i32 [ [[SELECT]], [[LOOP1]] ], [ [[TMP10]], [[MIDDLE_BLOCK]] ]
; CHECK-NEXT:    ret i32 [[SELECT_LCSSA]]
;
entry:
  %inv_cond = icmp eq i32 %a, %b
  br label %loop

loop:
  %iv = phi i32 [ %iv.start, %entry ], [ %iv.next, %loop ]
  %rdx = phi i32 [ 0, %entry ], [ %select, %loop ]
  %select = select i1 %inv_cond, i32 %rdx, i32 %iv
  %iv.next = add i32 %iv, 1
  %exit.cond = icmp sgt i32 %iv, 0
  br i1 %exit.cond, label %exit, label %loop

exit:
  ret i32 %select
}

define ptr @loop_inv_select_condition_issue_185682(i32 %a, i32 %b) {
; CHECK-LABEL: @loop_inv_select_condition_issue_185682(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[INV_COND:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT:    br label [[VECTOR_PH:%.*]]
; CHECK:       vector.ph:
; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i1> poison, i1 [[INV_COND]], i64 0
; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i1> [[BROADCAST_SPLATINSERT]], <4 x i1> poison, <4 x i32> zeroinitializer
; CHECK-NEXT:    [[TMP0:%.*]] = xor <4 x i1> [[BROADCAST_SPLAT]], splat (i1 true)
; CHECK-NEXT:    [[TMP1:%.*]] = freeze <4 x i1> [[TMP0]]
; CHECK-NEXT:    [[TMP2:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP1]])
; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
; CHECK:       vector.body:
; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[TMP2]], <4 x i1> [[TMP0]], <4 x i1> zeroinitializer
; CHECK-NEXT:    br label [[MIDDLE_BLOCK:%.*]]
; CHECK:       middle.block:
; CHECK-NEXT:    [[TMP6:%.*]] = call ptr @llvm.experimental.vector.extract.last.active.v4p0(<4 x ptr> zeroinitializer, <4 x i1> [[TMP3]], ptr null)
; CHECK-NEXT:    br label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    ret ptr [[TMP6]]
;
entry:
  %inv.cond = icmp eq i32 %a, %b
  br label %loop

loop:
  %rdx = phi ptr [ null, %entry ], [ %select, %loop ]
  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
  %select = select i1 %inv.cond, ptr %rdx, ptr null
  %iv.next = add i64 %iv, 1
  %exit.cond = icmp eq i64 %iv.next, 4
  br i1 %exit.cond, label %exit, label %loop

exit:
  ret ptr %select
}