; LLVM IR from kenjin/Awesome-LC-C-Cracker :: leetcode-c-sol/1137_n-th-tribonacci-number (1137_n-th-tribonacci-number)

; 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: nounwind uwtable
define dso_local i32 @tribonacci(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  %9 = load i32, ptr %3, align 4, !tbaa !5
  %10 = icmp slt i32 %9, 3
  br i1 %10, label %11, label %16

11:                                               ; preds = %1
  %12 = load i32, ptr %3, align 4, !tbaa !5
  %13 = icmp eq i32 %12, 0
  %14 = zext i1 %13 to i64
  %15 = select i1 %13, i32 0, i32 1
  store i32 %15, ptr %2, align 4
  br label %36

16:                                               ; preds = %1
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  store i32 0, ptr %4, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #2
  store i32 1, ptr %5, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #2
  store i32 1, ptr %6, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #2
  store i32 3, ptr %7, align 4, !tbaa !5
  br label %17

17:                                               ; preds = %31, %16
  %18 = load i32, ptr %7, align 4, !tbaa !5
  %19 = load i32, ptr %3, align 4, !tbaa !5
  %20 = icmp sle i32 %18, %19
  br i1 %20, label %22, label %21

21:                                               ; preds = %17
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #2
  br label %34

22:                                               ; preds = %17
  call void @llvm.lifetime.start.p0(i64 4, ptr %8) #2
  %23 = load i32, ptr %4, align 4, !tbaa !5
  %24 = load i32, ptr %5, align 4, !tbaa !5
  %25 = add nsw i32 %23, %24
  %26 = load i32, ptr %6, align 4, !tbaa !5
  %27 = add nsw i32 %25, %26
  store i32 %27, ptr %8, align 4, !tbaa !5
  %28 = load i32, ptr %5, align 4, !tbaa !5
  store i32 %28, ptr %4, align 4, !tbaa !5
  %29 = load i32, ptr %6, align 4, !tbaa !5
  store i32 %29, ptr %5, align 4, !tbaa !5
  %30 = load i32, ptr %8, align 4, !tbaa !5
  store i32 %30, ptr %6, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %8) #2
  br label %31

31:                                               ; preds = %22
  %32 = load i32, ptr %7, align 4, !tbaa !5
  %33 = add nsw i32 %32, 1
  store i32 %33, ptr %7, align 4, !tbaa !5
  br label %17, !llvm.loop !9

34:                                               ; preds = %21
  %35 = load i32, ptr %6, align 4, !tbaa !5
  store i32 %35, ptr %2, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  br label %36

36:                                               ; preds = %34, %11
  %37 = load i32, ptr %2, align 4
  ret i32 %37
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #1

attributes #0 = { 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 willreturn memory(argmem: readwrite) }
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/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: nofree norecurse nosync nounwind memory(none) uwtable
define dso_local i32 @tribonacci(i32 noundef %0) local_unnamed_addr #0 {
  %2 = icmp slt i32 %0, 3
  br i1 %2, label %6, label %.preheader.preheader

.preheader.preheader:                             ; preds = %1
  %3 = add nsw i32 %0, -2
  %4 = add nsw i32 %0, -3
  %xtraiter = and i32 %3, 7
  %5 = icmp ult i32 %4, 7
  br i1 %5, label %.loopexit.loopexit.unr-lcssa, label %.preheader.preheader.new

.preheader.preheader.new:                         ; preds = %.preheader.preheader
  %unroll_iter = and i32 %3, -8
  br label %.preheader

6:                                                ; preds = %1
  %7 = icmp ne i32 %0, 0
  %8 = zext i1 %7 to i32
  br label %.loopexit

.preheader:                                       ; preds = %.preheader, %.preheader.preheader.new
  %.01420 = phi i32 [ 1, %.preheader.preheader.new ], [ %24, %.preheader ]
  %.01519 = phi i32 [ 1, %.preheader.preheader.new ], [ %22, %.preheader ]
  %.01618 = phi i32 [ 0, %.preheader.preheader.new ], [ %20, %.preheader ]
  %niter = phi i32 [ 0, %.preheader.preheader.new ], [ %niter.next.7, %.preheader ]
  %9 = add nsw i32 %.01519, %.01618
  %10 = add nsw i32 %9, %.01420
  %11 = add nsw i32 %.01420, %.01519
  %12 = add nsw i32 %11, %10
  %13 = add nsw i32 %10, %.01420
  %14 = add nsw i32 %13, %12
  %15 = add nsw i32 %12, %10
  %16 = add nsw i32 %15, %14
  %17 = add nsw i32 %14, %12
  %18 = add nsw i32 %17, %16
  %19 = add nsw i32 %16, %14
  %20 = add nsw i32 %19, %18
  %21 = add nsw i32 %18, %16
  %22 = add nsw i32 %21, %20
  %23 = add nsw i32 %20, %18
  %24 = add nsw i32 %23, %22
  %niter.next.7 = add i32 %niter, 8
  %niter.ncmp.7 = icmp eq i32 %niter.next.7, %unroll_iter
  br i1 %niter.ncmp.7, label %.loopexit.loopexit.unr-lcssa, label %.preheader, !llvm.loop !5

.loopexit.loopexit.unr-lcssa:                     ; preds = %.preheader, %.preheader.preheader
  %.lcssa.ph = phi i32 [ poison, %.preheader.preheader ], [ %24, %.preheader ]
  %.01420.unr = phi i32 [ 1, %.preheader.preheader ], [ %24, %.preheader ]
  %.01519.unr = phi i32 [ 1, %.preheader.preheader ], [ %22, %.preheader ]
  %.01618.unr = phi i32 [ 0, %.preheader.preheader ], [ %20, %.preheader ]
  %lcmp.mod.not = icmp eq i32 %xtraiter, 0
  br i1 %lcmp.mod.not, label %.loopexit, label %.preheader.epil

.preheader.epil:                                  ; preds = %.loopexit.loopexit.unr-lcssa, %.preheader.epil
  %.01420.epil = phi i32 [ %26, %.preheader.epil ], [ %.01420.unr, %.loopexit.loopexit.unr-lcssa ]
  %.01519.epil = phi i32 [ %.01420.epil, %.preheader.epil ], [ %.01519.unr, %.loopexit.loopexit.unr-lcssa ]
  %.01618.epil = phi i32 [ %.01519.epil, %.preheader.epil ], [ %.01618.unr, %.loopexit.loopexit.unr-lcssa ]
  %epil.iter = phi i32 [ %epil.iter.next, %.preheader.epil ], [ 0, %.loopexit.loopexit.unr-lcssa ]
  %25 = add nsw i32 %.01519.epil, %.01618.epil
  %26 = add nsw i32 %25, %.01420.epil
  %epil.iter.next = add i32 %epil.iter, 1
  %epil.iter.cmp.not = icmp eq i32 %epil.iter.next, %xtraiter
  br i1 %epil.iter.cmp.not, label %.loopexit, label %.preheader.epil, !llvm.loop !7

.loopexit:                                        ; preds = %.loopexit.loopexit.unr-lcssa, %.preheader.epil, %6
  %.0 = phi i32 [ %8, %6 ], [ %.lcssa.ph, %.loopexit.loopexit.unr-lcssa ], [ %26, %.preheader.epil ]
  ret i32 %.0
}

attributes #0 = { nofree norecurse nosync nounwind memory(none) 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" }

!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"}
!7 = distinct !{!7, !8}
!8 = !{!"llvm.loop.unroll.disable"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass