; LLVM IR from evanxg852000/rockstartdev :: modern-cpp/chap1/core.ll (Z13largest_primej)

; Unoptimized IR (clang -disable-llvm-passes):
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef zeroext i1 @_Z8is_primei(i32 noundef) #1

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z13largest_primej(i32 noundef %0) #1 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  %6 = load i32, ptr %3, align 4, !tbaa !5
  store i32 %6, ptr %4, align 4, !tbaa !5
  br label %7

7:                                                ; preds = %17, %1
  %8 = load i32, ptr %4, align 4, !tbaa !5
  %9 = icmp ugt i32 %8, 1
  br i1 %9, label %11, label %10

10:                                               ; preds = %7
  store i32 2, ptr %5, align 4
  br label %20

11:                                               ; preds = %7
  %12 = load i32, ptr %4, align 4, !tbaa !5
  %13 = call noundef zeroext i1 @_Z8is_primei(i32 noundef %12)
  br i1 %13, label %14, label %16

14:                                               ; preds = %11
  %15 = load i32, ptr %4, align 4, !tbaa !5
  store i32 %15, ptr %2, align 4
  store i32 1, ptr %5, align 4
  br label %20

16:                                               ; preds = %11
  br label %17

17:                                               ; preds = %16
  %18 = load i32, ptr %4, align 4, !tbaa !5
  %19 = add i32 %18, -1
  store i32 %19, ptr %4, align 4, !tbaa !5
  br label %7, !llvm.loop !9

20:                                               ; preds = %14, %10
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  %21 = load i32, ptr %5, align 4
  switch i32 %21, label %25 [
    i32 2, label %22
    i32 1, label %23
  ]

22:                                               ; preds = %20
  store i32 2, ptr %2, align 4
  br label %23

23:                                               ; preds = %22, %20
  %24 = load i32, ptr %2, align 4
  ret i32 %24

25:                                               ; preds = %20
  unreachable
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #2 = { nounwind }

!llvm.module.flags = !{!0, !1, !2, !3}
!llvm.ident = !{!4}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{i32 7, !"uwtable", i32 2}
!4 = !{!"clang version 19.1.0 (git@github.com:llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4)"}
!5 = !{!6, !6, i64 0}
!6 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}


; Optimized IR (opt -passes='default<O3>'):
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef zeroext i1 @_Z8is_primei(i32 noundef) local_unnamed_addr #0

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z13largest_primej(i32 noundef %0) local_unnamed_addr #0 {
  %2 = icmp ult i32 %0, 2
  br i1 %2, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %1, %4
  %.079 = phi i32 [ %5, %4 ], [ %0, %1 ]
  %3 = tail call noundef zeroext i1 @_Z8is_primei(i32 noundef %.079)
  br i1 %3, label %._crit_edge, label %4

4:                                                ; preds = %.lr.ph
  %5 = add i32 %.079, -1
  %6 = icmp ult i32 %.079, 3
  br i1 %6, label %._crit_edge, label %.lr.ph, !llvm.loop !5

._crit_edge:                                      ; preds = %4, %.lr.ph, %1
  %.07.lcssa = phi i32 [ %0, %1 ], [ %.079, %.lr.ph ], [ 1, %4 ]
  %spec.select = tail call i32 @llvm.umax.i32(i32 %.07.lcssa, i32 2)
  ret i32 %spec.select
}

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i32 @llvm.umax.i32(i32, i32) #1

attributes #0 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #1 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }

!llvm.module.flags = !{!0, !1, !2, !3}
!llvm.ident = !{!4}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{i32 7, !"uwtable", i32 2}
!4 = !{!"clang version 19.1.0 (git@github.com:llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4)"}
!5 = distinct !{!5, !6}
!6 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: CorrelatedValuePropagationPass,GlobalOptPass,IPSCCPPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,SROAPass,SimplifyCFGPass,TailCallElimPass