test/Transforms/LoopVectorize/early_exit_legality.ll - llvm-project/llvm - Git at Google

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
 ; REQUIRES: asserts
 ; RUN: opt -S < %s -p loop-vectorize -debug-only=loop-vectorize -force-vector-width=4 -disable-output 2>&1 | FileCheck %s

 declare void @init_mem(ptr, i64);

 ; == SOME LEGAL EXAMPLES ==

 ; The form of the induction variables requires SCEV predicates.
 define i32 @diff_exit_block_needs_scev_check(i32 %end) {
 ; CHECK-LABEL: LV: Checking a loop in 'diff_exit_block_needs_scev_check'
 ; CHECK:       Found an early exit loop with symbolic max backedge taken count: (-1 + (1 umax (zext i10 (trunc i32 %end to i10) to i32)))<nsw>
 ; CHECK-NEXT:  LV: We can vectorize this loop!
 ; CHECK-NOT:   LV: Not vectorizing:
 entry:
   %p1 = alloca [1024 x i32]
   %p2 = alloca [1024 x i32]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   %end.clamped = and i32 %end, 1023
   br label %for.body

 for.body:
   %ind = phi i8 [ %ind.next, %for.inc ], [ 0, %entry ]
   %gep.ind = phi i64 [ %gep.ind.next, %for.inc ], [ 0, %entry ]
   %arrayidx1 = getelementptr inbounds i32, ptr %p1, i64 %gep.ind
   %0 = load i32, ptr %arrayidx1, align 4
   %arrayidx2 = getelementptr inbounds i32, ptr %p2, i64 %gep.ind
   %1 = load i32, ptr %arrayidx2, align 4
   %cmp.early = icmp eq i32 %0, %1
   br i1 %cmp.early, label %found, label %for.inc

 for.inc:
   %ind.next = add i8 %ind, 1
   %conv = zext i8 %ind.next to i32
   %gep.ind.next = add i64 %gep.ind, 1
   %cmp = icmp ult i32 %conv, %end.clamped
   br i1 %cmp, label %for.body, label %exit

 found:
   ret i32 1

 exit:
   ret i32 0
 }


 define i64 @same_exit_block_pre_inc_use1() {
 ; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_pre_inc_use1'
 ; CHECK:       LV: Found an early exit loop with symbolic max backedge taken count: 63
 ; CHECK-NEXT:  LV: We can vectorize this loop!
 ; CHECK-NOT:   LV: Not vectorizing
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i8, ptr %arrayidx, align 1
   %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
   %ld2 = load i8, ptr %arrayidx1, align 1
   %cmp3 = icmp eq i8 %ld1, %ld2
   br i1 %cmp3, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
   ret i64 %retval
 }


 define i64 @loop_contains_safe_call() {
 ; CHECK-LABEL: LV: Checking a loop in 'loop_contains_safe_call'
 ; CHECK:       LV: Found an early exit loop with symbolic max backedge taken count: 63
 ; CHECK-NEXT:  LV: We can vectorize this loop!
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds float, ptr %p1, i64 %index
   %ld1 = load float, ptr %arrayidx, align 1
   %sqrt = tail call fast float @llvm.sqrt.f32(float %ld1)
   %cmp = fcmp fast ult float %sqrt, 3.0e+00
   br i1 %cmp, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
   ret i64 %retval
 }


 define i64 @loop_contains_safe_div() {
 ; CHECK-LABEL: LV: Checking a loop in 'loop_contains_safe_div'
 ; CHECK:       LV: Found an early exit loop with symbolic max backedge taken count: 63
 ; CHECK-NEXT:  LV: We can vectorize this loop!
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i32, ptr %p1, i64 %index
   %ld1 = load i32, ptr %arrayidx, align 1
   %div = udiv i32 %ld1, 20000
   %cmp = icmp eq i32 %div, 1
   br i1 %cmp, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
   ret i64 %retval
 }


 define i64 @loop_contains_load_after_early_exit(ptr dereferenceable(1024) align(8) %p2) {
 ; CHECK-LABEL: LV: Checking a loop in 'loop_contains_load_after_early_exit'
 ; CHECK:       LV: Found an early exit loop with symbolic max backedge taken count: 63
 ; CHECK-NEXT:  LV: We can vectorize this loop!
 ; CHECK-NOT:   LV: Not vectorizing
 entry:
   %p1 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i32, ptr %p1, i64 %index
   %ld1 = load i32, ptr %arrayidx, align 1
   %cmp = icmp eq i32 %ld1, 1
   br i1 %cmp, label %loop.inc, label %loop.end

 loop.inc:
   %arrayidx2 = getelementptr inbounds i64, ptr %p2, i64 %index
   %ld2 = load i64, ptr %arrayidx2, align 8
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %loop ], [ %ld2, %loop.inc ]
   ret i64 %retval
 }


 define i64 @one_uncountable_two_countable_same_exit_phi_of_consts() {
 ; CHECK-LABEL: LV: Checking a loop in 'one_uncountable_two_countable_same_exit_phi_of_consts'
 ; CHECK:       LV: Found an early exit loop with symbolic max backedge taken count: 61
 ; CHECK-NEXT:  LV: We can vectorize this loop!
 ; CHECK-NEXT:  LV: Not vectorizing: Auto-vectorization of early exit loops requiring a scalar epilogue is unsupported.
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %cmp1 = icmp ne i64 %index, 64
   br i1 %cmp1, label %search, label %loop.end

 search:
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i8, ptr %arrayidx, align 1
   %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
   %ld2 = load i8, ptr %arrayidx1, align 1
   %cmp3 = icmp eq i8 %ld1, %ld2
   br i1 %cmp3, label %loop.end, label %loop.inc

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 128
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ 0, %loop ], [ 1, %search ], [ 0, %loop.inc ]
   ret i64 %retval
 }


 ; == SOME ILLEGAL EXAMPLES ==


 define i64 @same_exit_block_pre_inc_use1_too_small_allocas() {
 ; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_pre_inc_use1_too_small_allocas'
 ; CHECK:       LV: Not vectorizing: Auto-vectorization of loops with potentially faulting load is not supported.
 entry:
   %p1 = alloca [42 x i8]
   %p2 = alloca [42 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i8, ptr %arrayidx, align 1
   %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
   %ld2 = load i8, ptr %arrayidx1, align 1
   %cmp3 = icmp eq i8 %ld1, %ld2
   br i1 %cmp3, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
   ret i64 %retval
 }


 define i64 @same_exit_block_pre_inc_use1_too_small_deref_ptrs(ptr dereferenceable(42) %p1, ptr dereferenceable(42) %p2) {
 ; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_pre_inc_use1_too_small_deref_ptrs'
 ; CHECK:       LV: Not vectorizing: Auto-vectorization of loops with potentially faulting load is not supported.
 entry:
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i8, ptr %arrayidx, align 1
   %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
   %ld2 = load i8, ptr %arrayidx1, align 1
   %cmp3 = icmp eq i8 %ld1, %ld2
   br i1 %cmp3, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
   ret i64 %retval
 }


 define i64 @same_exit_block_pre_inc_use1_unknown_ptrs(ptr %p1, ptr %p2) {
 ; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_pre_inc_use1_unknown_ptrs'
 ; CHECK:       LV: Not vectorizing: Auto-vectorization of loops with potentially faulting load is not supported.
 entry:
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i8, ptr %arrayidx, align 1
   %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
   %ld2 = load i8, ptr %arrayidx1, align 1
   %cmp3 = icmp eq i8 %ld1, %ld2
   br i1 %cmp3, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
   ret i64 %retval
 }

 define ptr @same_exit_block_strided_unknown_ptr(ptr %first, ptr %last, i32 %value) {
 ; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_strided_unknown_ptr'
 ; CHECK:       LV: Not vectorizing: Loop contains potentially faulting strided load.
 entry:
   %cond = icmp eq ptr %first, %last
   br i1 %cond, label %return, label %for.body

 for.body:
   %first.addr = phi ptr [ %first, %entry ], [ %first.next, %for.inc ]
   %1 = load i32, ptr %first.addr, align 4
   %cond2 = icmp eq i32 %1, %value
   br i1 %cond2, label %for.end, label %for.inc

 for.inc:
   %first.next = getelementptr inbounds i32, ptr %first.addr, i64 2
   %cond3 = icmp eq ptr %first.next, %last
   br i1 %cond3, label %for.end, label %for.body

 for.end:
   %retval.ph = phi ptr [ %first.addr, %for.body ], [ %last, %for.inc ]
   br label %return

 return:
   %retval = phi ptr [ %first, %entry ], [ %retval.ph, %for.end ]
   ret ptr %retval
 }

 ; The early exit (i.e. unknown exit-not-taken count) is the latch - we don't
 ; support this yet.
 define i64 @uncountable_exit_on_last_block() {
 ; CHECK-LABEL: LV: Checking a loop in 'uncountable_exit_on_last_block'
 ; CHECK:       LV: Not vectorizing: Early exit is not the latch predecessor.
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %search ], [ 3, %entry ]
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %search, label %loop.end

 search:
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i8, ptr %arrayidx, align 1
   %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
   %ld2 = load i8, ptr %arrayidx1, align 1
   %cmp3 = icmp eq i8 %ld1, %ld2
   br i1 %cmp3, label %loop.end, label %loop

 loop.end:
   %retval = phi i64 [ 64, %loop ], [ %index, %search ]
   ret i64 %retval
 }


 ; We don't currently support multiple uncountable early exits.
 define i64 @multiple_uncountable_exits() {
 ; CHECK-LABEL: LV: Checking a loop in 'multiple_uncountable_exits'
 ; CHECK:       LV: Not vectorizing: Loop has too many uncountable exits.
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %search1

 search1:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i8, ptr %arrayidx, align 1
   %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
   %ld2 = load i8, ptr %arrayidx1, align 1
   %cmp1 = icmp eq i8 %ld1, %ld2
   br i1 %cmp1, label %loop.end, label %search2

 search2:
   %cmp2 = icmp ult i8 %ld1, 34
   br i1 %cmp2, label %loop.end, label %loop.inc

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %search1, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %search1 ], [ 100, %search2 ], [ 43, %loop.inc ]
   ret i64 %retval
 }


 define i64 @uncountable_exit_infinite_loop() {
 ; CHECK-LABEL: LV: Checking a loop in 'uncountable_exit_infinite_loop'
 ; CHECK:       LV: Not vectorizing: Cannot vectorize uncountable loop.
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i8, ptr %arrayidx, align 1
   %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
   %ld2 = load i8, ptr %arrayidx1, align 1
   %cmp3 = icmp eq i8 %ld1, %ld2
   br i1 %cmp3, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br label %loop

 loop.end:
   %retval = phi i64 [ %index, %loop ]
   ret i64 %retval
 }


 define i64 @loop_contains_unsafe_call() {
 ; CHECK-LABEL: LV: Checking a loop in 'loop_contains_unsafe_call'
 ; CHECK:       LV: Not vectorizing: Early exit loop contains operations that cannot be speculatively executed.
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i32, ptr %p1, i64 %index
   %ld1 = load i32, ptr %arrayidx, align 1
   %bad_call = call i32 @foo(i32 %ld1) #0
   %cmp = icmp eq i32 %bad_call, 34
   br i1 %cmp, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
   ret i64 %retval
 }


 define i64 @loop_contains_unsafe_div() {
 ; CHECK-LABEL: LV: Checking a loop in 'loop_contains_unsafe_div'
 ; CHECK:       LV: Not vectorizing: Early exit loop contains operations that cannot be speculatively executed.
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i32, ptr %arrayidx, align 1
   %div = udiv i32 20000, %ld1
   %cmp = icmp eq i32 %div, 1
   br i1 %cmp, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
   ret i64 %retval
 }

 define void @exit_conditions_combined_in_single_branch(ptr noalias dereferenceable(40) %array, ptr readonly align 2 dereferenceable(40) %pred) {
 ; CHECK-LABEL: LV: Checking a loop in 'exit_conditions_combined_in_single_branch'
 ; CHECK:       LV: Not vectorizing: Cannot vectorize uncountable loop.
 entry:
   br label %for.body

 for.body:                                         ; preds = %for.body, %entry
   %iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
   %st.addr = getelementptr inbounds nuw i16, ptr %array, i64 %iv
   %data = load i16, ptr %st.addr, align 2
   %inc = add nsw i16 %data, 1
   store i16 %inc, ptr %st.addr, align 2
   %ee.addr = getelementptr inbounds nuw i16, ptr %pred, i64 %iv
   %ee.val = load i16, ptr %ee.addr, align 2
   %ee.cond = icmp sgt i16 %ee.val, 500
   %iv.next = add nuw nsw i64 %iv, 1
   %counted.cond = icmp eq i64 %iv.next, 20
   %or.cond = select i1 %ee.cond, i1 true, i1 %counted.cond
   br i1 %or.cond, label %exit, label %for.body

 exit:                                             ; preds = %for.body
   ret void
 }

 define i64 @uncountable_exit_in_conditional_block(ptr %mask) {
 ; CHECK-LABEL: LV: Checking a loop in 'uncountable_exit_in_conditional_block'
 ; CHECK:       LV: Not vectorizing: Early exit is not the latch predecessor.
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx1 = getelementptr inbounds i8, ptr %mask, i64 %index
   %ld1 = load i8, ptr %arrayidx1, align 1
   %cmp1 = icmp ne i8 %ld1, 0
   br i1 %cmp1, label %loop.search, label %loop.inc

 loop.search:
   %arrayidx2 = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld2 = load i8, ptr %arrayidx2, align 1
   %arrayidx3 = getelementptr inbounds i8, ptr %p2, i64 %index
   %ld3 = load i8, ptr %arrayidx3, align 1
   %cmp2 = icmp eq i8 %ld2, %ld3
   br i1 %cmp2, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %retval = phi i64 [ %index, %loop.search ], [ 67, %loop.inc ]
   ret i64 %retval
 }


 define i64 @same_exit_block_pre_inc_use1_with_reduction() {
 ; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_pre_inc_use1_with_reduction'
 ; CHECK:       LV: Not vectorizing: Found reductions or recurrences in early-exit loop.
 entry:
   %p1 = alloca [1024 x i8]
   %p2 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   call void @init_mem(ptr %p2, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %red = phi i64 [ %red.next, %loop.inc ], [ 0, %entry ]
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i8, ptr %arrayidx, align 1
   %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
   %ld2 = load i8, ptr %arrayidx1, align 1
   %ld2.zext = zext i8 %ld2 to i64
   %red.next = add i64 %red, %ld2.zext
   %cmp3 = icmp eq i8 %ld1, %ld2
   br i1 %cmp3, label %loop.inc, label %loop.end

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.end:
   %final.ind = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
   %retval = add i64 %red.next, %final.ind
   ret i64 %retval
 }


 define i64 @uncountable_exit_has_multiple_outside_successors() {
 ; CHECK-LABEL: LV: Checking a loop in 'uncountable_exit_has_multiple_outside_successors'
 ; CHECK:       LV: Not vectorizing: Loop contains an unsupported switch
 entry:
   %p1 = alloca [1024 x i8]
   call void @init_mem(ptr %p1, i64 1024)
   br label %loop

 loop:
   %index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
   %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
   %ld1 = load i8, ptr %arrayidx, align 1
   switch i8 %ld1, label %loop.inc [
   i8 2, label %loop.end
   i8 3, label %loop.surprise
   ]

 loop.inc:
   %index.next = add i64 %index, 1
   %exitcond = icmp ne i64 %index.next, 67
   br i1 %exitcond, label %loop, label %loop.end

 loop.surprise:
   ret i64 3

 loop.end:
   %retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
   ret i64 %retval
 }


 declare i32 @foo(i32) readonly
 declare <vscale x 4 x i32> @foo_vec(<vscale x 4 x i32>)

 attributes #0 = { "vector-function-abi-variant"="_ZGVsNxv_foo(foo_vec)" }
	; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
	; REQUIRES: asserts
	; RUN: opt -S < %s -p loop-vectorize -debug-only=loop-vectorize -force-vector-width=4 -disable-output 2>&1 \| FileCheck %s

	declare void @init_mem(ptr, i64);

	; == SOME LEGAL EXAMPLES ==

	; The form of the induction variables requires SCEV predicates.
	define i32 @diff_exit_block_needs_scev_check(i32 %end) {
	; CHECK-LABEL: LV: Checking a loop in 'diff_exit_block_needs_scev_check'
	; CHECK: Found an early exit loop with symbolic max backedge taken count: (-1 + (1 umax (zext i10 (trunc i32 %end to i10) to i32)))<nsw>
	; CHECK-NEXT: LV: We can vectorize this loop!
	; CHECK-NOT: LV: Not vectorizing:
	entry:
	%p1 = alloca [1024 x i32]
	%p2 = alloca [1024 x i32]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	%end.clamped = and i32 %end, 1023
	br label %for.body

	for.body:
	%ind = phi i8 [ %ind.next, %for.inc ], [ 0, %entry ]
	%gep.ind = phi i64 [ %gep.ind.next, %for.inc ], [ 0, %entry ]
	%arrayidx1 = getelementptr inbounds i32, ptr %p1, i64 %gep.ind
	%0 = load i32, ptr %arrayidx1, align 4
	%arrayidx2 = getelementptr inbounds i32, ptr %p2, i64 %gep.ind
	%1 = load i32, ptr %arrayidx2, align 4
	%cmp.early = icmp eq i32 %0, %1
	br i1 %cmp.early, label %found, label %for.inc

	for.inc:
	%ind.next = add i8 %ind, 1
	%conv = zext i8 %ind.next to i32
	%gep.ind.next = add i64 %gep.ind, 1
	%cmp = icmp ult i32 %conv, %end.clamped
	br i1 %cmp, label %for.body, label %exit

	found:
	ret i32 1

	exit:
	ret i32 0
	}


	define i64 @same_exit_block_pre_inc_use1() {
	; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_pre_inc_use1'
	; CHECK: LV: Found an early exit loop with symbolic max backedge taken count: 63
	; CHECK-NEXT: LV: We can vectorize this loop!
	; CHECK-NOT: LV: Not vectorizing
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i8, ptr %arrayidx, align 1
	%arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
	%ld2 = load i8, ptr %arrayidx1, align 1
	%cmp3 = icmp eq i8 %ld1, %ld2
	br i1 %cmp3, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
	ret i64 %retval
	}


	define i64 @loop_contains_safe_call() {
	; CHECK-LABEL: LV: Checking a loop in 'loop_contains_safe_call'
	; CHECK: LV: Found an early exit loop with symbolic max backedge taken count: 63
	; CHECK-NEXT: LV: We can vectorize this loop!
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds float, ptr %p1, i64 %index
	%ld1 = load float, ptr %arrayidx, align 1
	%sqrt = tail call fast float @llvm.sqrt.f32(float %ld1)
	%cmp = fcmp fast ult float %sqrt, 3.0e+00
	br i1 %cmp, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
	ret i64 %retval
	}


	define i64 @loop_contains_safe_div() {
	; CHECK-LABEL: LV: Checking a loop in 'loop_contains_safe_div'
	; CHECK: LV: Found an early exit loop with symbolic max backedge taken count: 63
	; CHECK-NEXT: LV: We can vectorize this loop!
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i32, ptr %p1, i64 %index
	%ld1 = load i32, ptr %arrayidx, align 1
	%div = udiv i32 %ld1, 20000
	%cmp = icmp eq i32 %div, 1
	br i1 %cmp, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
	ret i64 %retval
	}


	define i64 @loop_contains_load_after_early_exit(ptr dereferenceable(1024) align(8) %p2) {
	; CHECK-LABEL: LV: Checking a loop in 'loop_contains_load_after_early_exit'
	; CHECK: LV: Found an early exit loop with symbolic max backedge taken count: 63
	; CHECK-NEXT: LV: We can vectorize this loop!
	; CHECK-NOT: LV: Not vectorizing
	entry:
	%p1 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i32, ptr %p1, i64 %index
	%ld1 = load i32, ptr %arrayidx, align 1
	%cmp = icmp eq i32 %ld1, 1
	br i1 %cmp, label %loop.inc, label %loop.end

	loop.inc:
	%arrayidx2 = getelementptr inbounds i64, ptr %p2, i64 %index
	%ld2 = load i64, ptr %arrayidx2, align 8
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %loop ], [ %ld2, %loop.inc ]
	ret i64 %retval
	}


	define i64 @one_uncountable_two_countable_same_exit_phi_of_consts() {
	; CHECK-LABEL: LV: Checking a loop in 'one_uncountable_two_countable_same_exit_phi_of_consts'
	; CHECK: LV: Found an early exit loop with symbolic max backedge taken count: 61
	; CHECK-NEXT: LV: We can vectorize this loop!
	; CHECK-NEXT: LV: Not vectorizing: Auto-vectorization of early exit loops requiring a scalar epilogue is unsupported.
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%cmp1 = icmp ne i64 %index, 64
	br i1 %cmp1, label %search, label %loop.end

	search:
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i8, ptr %arrayidx, align 1
	%arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
	%ld2 = load i8, ptr %arrayidx1, align 1
	%cmp3 = icmp eq i8 %ld1, %ld2
	br i1 %cmp3, label %loop.end, label %loop.inc

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 128
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ 0, %loop ], [ 1, %search ], [ 0, %loop.inc ]
	ret i64 %retval
	}


	; == SOME ILLEGAL EXAMPLES ==


	define i64 @same_exit_block_pre_inc_use1_too_small_allocas() {
	; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_pre_inc_use1_too_small_allocas'
	; CHECK: LV: Not vectorizing: Auto-vectorization of loops with potentially faulting load is not supported.
	entry:
	%p1 = alloca [42 x i8]
	%p2 = alloca [42 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i8, ptr %arrayidx, align 1
	%arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
	%ld2 = load i8, ptr %arrayidx1, align 1
	%cmp3 = icmp eq i8 %ld1, %ld2
	br i1 %cmp3, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
	ret i64 %retval
	}


	define i64 @same_exit_block_pre_inc_use1_too_small_deref_ptrs(ptr dereferenceable(42) %p1, ptr dereferenceable(42) %p2) {
	; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_pre_inc_use1_too_small_deref_ptrs'
	; CHECK: LV: Not vectorizing: Auto-vectorization of loops with potentially faulting load is not supported.
	entry:
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i8, ptr %arrayidx, align 1
	%arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
	%ld2 = load i8, ptr %arrayidx1, align 1
	%cmp3 = icmp eq i8 %ld1, %ld2
	br i1 %cmp3, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
	ret i64 %retval
	}


	define i64 @same_exit_block_pre_inc_use1_unknown_ptrs(ptr %p1, ptr %p2) {
	; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_pre_inc_use1_unknown_ptrs'
	; CHECK: LV: Not vectorizing: Auto-vectorization of loops with potentially faulting load is not supported.
	entry:
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i8, ptr %arrayidx, align 1
	%arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
	%ld2 = load i8, ptr %arrayidx1, align 1
	%cmp3 = icmp eq i8 %ld1, %ld2
	br i1 %cmp3, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
	ret i64 %retval
	}

	define ptr @same_exit_block_strided_unknown_ptr(ptr %first, ptr %last, i32 %value) {
	; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_strided_unknown_ptr'
	; CHECK: LV: Not vectorizing: Loop contains potentially faulting strided load.
	entry:
	%cond = icmp eq ptr %first, %last
	br i1 %cond, label %return, label %for.body

	for.body:
	%first.addr = phi ptr [ %first, %entry ], [ %first.next, %for.inc ]
	%1 = load i32, ptr %first.addr, align 4
	%cond2 = icmp eq i32 %1, %value
	br i1 %cond2, label %for.end, label %for.inc

	for.inc:
	%first.next = getelementptr inbounds i32, ptr %first.addr, i64 2
	%cond3 = icmp eq ptr %first.next, %last
	br i1 %cond3, label %for.end, label %for.body

	for.end:
	%retval.ph = phi ptr [ %first.addr, %for.body ], [ %last, %for.inc ]
	br label %return

	return:
	%retval = phi ptr [ %first, %entry ], [ %retval.ph, %for.end ]
	ret ptr %retval
	}

	; The early exit (i.e. unknown exit-not-taken count) is the latch - we don't
	; support this yet.
	define i64 @uncountable_exit_on_last_block() {
	; CHECK-LABEL: LV: Checking a loop in 'uncountable_exit_on_last_block'
	; CHECK: LV: Not vectorizing: Early exit is not the latch predecessor.
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %search ], [ 3, %entry ]
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %search, label %loop.end

	search:
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i8, ptr %arrayidx, align 1
	%arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
	%ld2 = load i8, ptr %arrayidx1, align 1
	%cmp3 = icmp eq i8 %ld1, %ld2
	br i1 %cmp3, label %loop.end, label %loop

	loop.end:
	%retval = phi i64 [ 64, %loop ], [ %index, %search ]
	ret i64 %retval
	}


	; We don't currently support multiple uncountable early exits.
	define i64 @multiple_uncountable_exits() {
	; CHECK-LABEL: LV: Checking a loop in 'multiple_uncountable_exits'
	; CHECK: LV: Not vectorizing: Loop has too many uncountable exits.
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %search1

	search1:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i8, ptr %arrayidx, align 1
	%arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
	%ld2 = load i8, ptr %arrayidx1, align 1
	%cmp1 = icmp eq i8 %ld1, %ld2
	br i1 %cmp1, label %loop.end, label %search2

	search2:
	%cmp2 = icmp ult i8 %ld1, 34
	br i1 %cmp2, label %loop.end, label %loop.inc

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %search1, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %search1 ], [ 100, %search2 ], [ 43, %loop.inc ]
	ret i64 %retval
	}


	define i64 @uncountable_exit_infinite_loop() {
	; CHECK-LABEL: LV: Checking a loop in 'uncountable_exit_infinite_loop'
	; CHECK: LV: Not vectorizing: Cannot vectorize uncountable loop.
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i8, ptr %arrayidx, align 1
	%arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
	%ld2 = load i8, ptr %arrayidx1, align 1
	%cmp3 = icmp eq i8 %ld1, %ld2
	br i1 %cmp3, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br label %loop

	loop.end:
	%retval = phi i64 [ %index, %loop ]
	ret i64 %retval
	}


	define i64 @loop_contains_unsafe_call() {
	; CHECK-LABEL: LV: Checking a loop in 'loop_contains_unsafe_call'
	; CHECK: LV: Not vectorizing: Early exit loop contains operations that cannot be speculatively executed.
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i32, ptr %p1, i64 %index
	%ld1 = load i32, ptr %arrayidx, align 1
	%bad_call = call i32 @foo(i32 %ld1) #0
	%cmp = icmp eq i32 %bad_call, 34
	br i1 %cmp, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
	ret i64 %retval
	}


	define i64 @loop_contains_unsafe_div() {
	; CHECK-LABEL: LV: Checking a loop in 'loop_contains_unsafe_div'
	; CHECK: LV: Not vectorizing: Early exit loop contains operations that cannot be speculatively executed.
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i32, ptr %arrayidx, align 1
	%div = udiv i32 20000, %ld1
	%cmp = icmp eq i32 %div, 1
	br i1 %cmp, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
	ret i64 %retval
	}

	define void @exit_conditions_combined_in_single_branch(ptr noalias dereferenceable(40) %array, ptr readonly align 2 dereferenceable(40) %pred) {
	; CHECK-LABEL: LV: Checking a loop in 'exit_conditions_combined_in_single_branch'
	; CHECK: LV: Not vectorizing: Cannot vectorize uncountable loop.
	entry:
	br label %for.body

	for.body: ; preds = %for.body, %entry
	%iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
	%st.addr = getelementptr inbounds nuw i16, ptr %array, i64 %iv
	%data = load i16, ptr %st.addr, align 2
	%inc = add nsw i16 %data, 1
	store i16 %inc, ptr %st.addr, align 2
	%ee.addr = getelementptr inbounds nuw i16, ptr %pred, i64 %iv
	%ee.val = load i16, ptr %ee.addr, align 2
	%ee.cond = icmp sgt i16 %ee.val, 500
	%iv.next = add nuw nsw i64 %iv, 1
	%counted.cond = icmp eq i64 %iv.next, 20
	%or.cond = select i1 %ee.cond, i1 true, i1 %counted.cond
	br i1 %or.cond, label %exit, label %for.body

	exit: ; preds = %for.body
	ret void
	}

	define i64 @uncountable_exit_in_conditional_block(ptr %mask) {
	; CHECK-LABEL: LV: Checking a loop in 'uncountable_exit_in_conditional_block'
	; CHECK: LV: Not vectorizing: Early exit is not the latch predecessor.
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx1 = getelementptr inbounds i8, ptr %mask, i64 %index
	%ld1 = load i8, ptr %arrayidx1, align 1
	%cmp1 = icmp ne i8 %ld1, 0
	br i1 %cmp1, label %loop.search, label %loop.inc

	loop.search:
	%arrayidx2 = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld2 = load i8, ptr %arrayidx2, align 1
	%arrayidx3 = getelementptr inbounds i8, ptr %p2, i64 %index
	%ld3 = load i8, ptr %arrayidx3, align 1
	%cmp2 = icmp eq i8 %ld2, %ld3
	br i1 %cmp2, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%retval = phi i64 [ %index, %loop.search ], [ 67, %loop.inc ]
	ret i64 %retval
	}


	define i64 @same_exit_block_pre_inc_use1_with_reduction() {
	; CHECK-LABEL: LV: Checking a loop in 'same_exit_block_pre_inc_use1_with_reduction'
	; CHECK: LV: Not vectorizing: Found reductions or recurrences in early-exit loop.
	entry:
	%p1 = alloca [1024 x i8]
	%p2 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	call void @init_mem(ptr %p2, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%red = phi i64 [ %red.next, %loop.inc ], [ 0, %entry ]
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i8, ptr %arrayidx, align 1
	%arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
	%ld2 = load i8, ptr %arrayidx1, align 1
	%ld2.zext = zext i8 %ld2 to i64
	%red.next = add i64 %red, %ld2.zext
	%cmp3 = icmp eq i8 %ld1, %ld2
	br i1 %cmp3, label %loop.inc, label %loop.end

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.end:
	%final.ind = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
	%retval = add i64 %red.next, %final.ind
	ret i64 %retval
	}


	define i64 @uncountable_exit_has_multiple_outside_successors() {
	; CHECK-LABEL: LV: Checking a loop in 'uncountable_exit_has_multiple_outside_successors'
	; CHECK: LV: Not vectorizing: Loop contains an unsupported switch
	entry:
	%p1 = alloca [1024 x i8]
	call void @init_mem(ptr %p1, i64 1024)
	br label %loop

	loop:
	%index = phi i64 [ %index.next, %loop.inc ], [ 3, %entry ]
	%arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
	%ld1 = load i8, ptr %arrayidx, align 1
	switch i8 %ld1, label %loop.inc [
	i8 2, label %loop.end
	i8 3, label %loop.surprise
	]

	loop.inc:
	%index.next = add i64 %index, 1
	%exitcond = icmp ne i64 %index.next, 67
	br i1 %exitcond, label %loop, label %loop.end

	loop.surprise:
	ret i64 3

	loop.end:
	%retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
	ret i64 %retval
	}


	declare i32 @foo(i32) readonly
	declare <vscale x 4 x i32> @foo_vec(<vscale x 4 x i32>)

	attributes #0 = { "vector-function-abi-variant"="_ZGVsNxv_foo(foo_vec)" }