; LLVM IR from CodersForLife/Data-Structures-Algorithms :: Structures/LinkedList.ll (Z3maxv)

; 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"

%struct.Node = type { i32, ptr }

@_ZL4head = external hidden global ptr, align 8

; 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
define dso_local noundef i32 @_Z3maxv() #1 {
  %1 = alloca i32, align 4
  %2 = alloca ptr, align 8
  call void @llvm.lifetime.start.p0(i64 4, ptr %1) #2
  store i32 0, ptr %1, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %2) #2
  %3 = load ptr, ptr @_ZL4head, align 8, !tbaa !9
  store ptr %3, ptr %2, align 8, !tbaa !9
  br label %4

4:                                                ; preds = %19, %0
  %5 = load ptr, ptr %2, align 8, !tbaa !9
  %6 = icmp ne ptr %5, null
  br i1 %6, label %8, label %7

7:                                                ; preds = %4
  call void @llvm.lifetime.end.p0(i64 8, ptr %2) #2
  br label %23

8:                                                ; preds = %4
  %9 = load ptr, ptr %2, align 8, !tbaa !9
  %10 = getelementptr inbounds %struct.Node, ptr %9, i32 0, i32 0
  %11 = load i32, ptr %10, align 8, !tbaa !11
  %12 = load i32, ptr %1, align 4, !tbaa !5
  %13 = icmp sgt i32 %11, %12
  br i1 %13, label %14, label %18

14:                                               ; preds = %8
  %15 = load ptr, ptr %2, align 8, !tbaa !9
  %16 = getelementptr inbounds %struct.Node, ptr %15, i32 0, i32 0
  %17 = load i32, ptr %16, align 8, !tbaa !11
  store i32 %17, ptr %1, align 4, !tbaa !5
  br label %18

18:                                               ; preds = %14, %8
  br label %19

19:                                               ; preds = %18
  %20 = load ptr, ptr %2, align 8, !tbaa !9
  %21 = getelementptr inbounds %struct.Node, ptr %20, i32 0, i32 1
  %22 = load ptr, ptr %21, align 8, !tbaa !13
  store ptr %22, ptr %2, align 8, !tbaa !9
  br label %4, !llvm.loop !14

23:                                               ; preds = %7
  %24 = load i32, ptr %1, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %1) #2
  ret i32 %24
}

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 = !{!10, !10, i64 0}
!10 = !{!"any pointer", !7, i64 0}
!11 = !{!12, !6, i64 0}
!12 = !{!"_ZTS4Node", !6, i64 0, !10, i64 8}
!13 = !{!12, !10, i64 8}
!14 = distinct !{!14, !15}
!15 = !{!"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"

@_ZL4head = external hidden local_unnamed_addr global ptr, align 8

; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(read, inaccessiblemem: none) uwtable
define dso_local noundef range(i32 0, -2147483648) i32 @_Z3maxv() local_unnamed_addr #0 {
  %.07 = load ptr, ptr @_ZL4head, align 8, !tbaa !5
  %.not8 = icmp eq ptr %.07, null
  br i1 %.not8, label %._crit_edge, label %.lr.ph

._crit_edge:                                      ; preds = %.lr.ph, %0
  %.05.lcssa = phi i32 [ 0, %0 ], [ %spec.select, %.lr.ph ]
  ret i32 %.05.lcssa

.lr.ph:                                           ; preds = %0, %.lr.ph
  %.010 = phi ptr [ %.0, %.lr.ph ], [ %.07, %0 ]
  %.059 = phi i32 [ %spec.select, %.lr.ph ], [ 0, %0 ]
  %1 = load i32, ptr %.010, align 8, !tbaa !9
  %spec.select = tail call i32 @llvm.smax.i32(i32 %1, i32 %.059)
  %2 = getelementptr inbounds i8, ptr %.010, i64 8
  %.0 = load ptr, ptr %2, align 8, !tbaa !5
  %.not = icmp eq ptr %.0, null
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !12
}

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

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(read, inaccessiblemem: 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" }
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 = !{!6, !6, i64 0}
!6 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !11, i64 0}
!10 = !{!"_ZTS4Node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}


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