; LLVM IR from xing1357/SimpleOS :: src (kheap)

; 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._kheap_block = type { %struct.anon, ptr, ptr }
%struct.anon = type { i32, i8 }

@g_head = external dso_local 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: nounwind uwtable
define dso_local void @kfree(ptr noundef %0) #1 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #2
  %5 = load ptr, ptr @g_head, align 8, !tbaa !5
  store ptr %5, ptr %3, align 8, !tbaa !5
  br label %6

6:                                                ; preds = %19, %1
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  %8 = icmp ne ptr %7, null
  br i1 %8, label %9, label %23

9:                                                ; preds = %6
  %10 = load ptr, ptr %3, align 8, !tbaa !5
  %11 = getelementptr inbounds %struct._kheap_block, ptr %10, i32 0, i32 2
  %12 = load ptr, ptr %11, align 1, !tbaa !9
  %13 = load ptr, ptr %2, align 8, !tbaa !5
  %14 = icmp eq ptr %12, %13
  br i1 %14, label %15, label %19

15:                                               ; preds = %9
  %16 = load ptr, ptr %3, align 8, !tbaa !5
  %17 = getelementptr inbounds %struct._kheap_block, ptr %16, i32 0, i32 0
  %18 = getelementptr inbounds %struct.anon, ptr %17, i32 0, i32 1
  store i8 1, ptr %18, align 1, !tbaa !13
  store i32 1, ptr %4, align 4
  br label %24

19:                                               ; preds = %9
  %20 = load ptr, ptr %3, align 8, !tbaa !5
  %21 = getelementptr inbounds %struct._kheap_block, ptr %20, i32 0, i32 1
  %22 = load ptr, ptr %21, align 1, !tbaa !14
  store ptr %22, ptr %3, align 8, !tbaa !5
  br label %6, !llvm.loop !15

23:                                               ; preds = %6
  store i32 0, ptr %4, align 4
  br label %24

24:                                               ; preds = %23, %15
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #2
  %25 = load i32, ptr %4, align 4
  switch i32 %25, label %27 [
    i32 0, label %26
    i32 1, label %26
  ]

26:                                               ; preds = %24, %24
  ret void

27:                                               ; preds = %24
  unreachable
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !6, i64 16}
!10 = !{!"_kheap_block", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"", !12, i64 0, !7, i64 4}
!12 = !{!"int", !7, i64 0}
!13 = !{!10, !7, i64 4}
!14 = !{!10, !6, i64 8}
!15 = distinct !{!15, !16}
!16 = !{!"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"

@g_head = external dso_local local_unnamed_addr global ptr, align 8

; Function Attrs: nofree norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local void @kfree(ptr noundef readnone %0) local_unnamed_addr #0 {
  %.06 = load ptr, ptr @g_head, align 8, !tbaa !5
  %.not7 = icmp eq ptr %.06, null
  br i1 %.not7, label %.loopexit, label %.lr.ph

.lr.ph:                                           ; preds = %1, %7
  %.08 = phi ptr [ %.0, %7 ], [ %.06, %1 ]
  %2 = getelementptr inbounds i8, ptr %.08, i64 16
  %3 = load ptr, ptr %2, align 1, !tbaa !9
  %4 = icmp eq ptr %3, %0
  br i1 %4, label %5, label %7

5:                                                ; preds = %.lr.ph
  %6 = getelementptr inbounds i8, ptr %.08, i64 4
  store i8 1, ptr %6, align 1, !tbaa !13
  br label %.loopexit

7:                                                ; preds = %.lr.ph
  %8 = getelementptr inbounds i8, ptr %.08, i64 8
  %.0 = load ptr, ptr %8, align 1, !tbaa !5
  %.not = icmp eq ptr %.0, null
  br i1 %.not, label %.loopexit, label %.lr.ph, !llvm.loop !14

.loopexit:                                        ; preds = %7, %1, %5
  ret void
}

attributes #0 = { nofree norecurse nosync nounwind memory(readwrite, 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" }

!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/C++ TBAA"}
!9 = !{!10, !6, i64 16}
!10 = !{!"_kheap_block", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"", !12, i64 0, !7, i64 4}
!12 = !{!"int", !7, i64 0}
!13 = !{!10, !7, i64 4}
!14 = distinct !{!14, !15}
!15 = !{!"llvm.loop.mustprogress"}


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