; LLVM IR from BrunoLevy/learn-fpga :: LiteX/software/Doom (sbrk)

; 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"

@sbrk.heap_end = external hidden global i64, align 8
@_end = external global [0 x i8], align 1

; Function Attrs: nounwind uwtable
define dso_local ptr @sbrk(i64 noundef %0) #0 {
  %2 = alloca i64, align 8
  store i64 %0, ptr %2, align 8, !tbaa !5
  %3 = load i64, ptr @sbrk.heap_end, align 8, !tbaa !5
  %4 = icmp eq i64 %3, 0
  br i1 %4, label %5, label %6

5:                                                ; preds = %1
  store i64 ptrtoint (ptr @_end to i64), ptr @sbrk.heap_end, align 8, !tbaa !5
  br label %6

6:                                                ; preds = %5, %1
  %7 = load i64, ptr %2, align 8, !tbaa !5
  %8 = load i64, ptr @sbrk.heap_end, align 8, !tbaa !5
  %9 = add i64 %8, %7
  store i64 %9, ptr @sbrk.heap_end, align 8, !tbaa !5
  %10 = load i64, ptr @sbrk.heap_end, align 8, !tbaa !5
  %11 = load i64, ptr %2, align 8, !tbaa !5
  %12 = sub i64 %10, %11
  %13 = inttoptr i64 %12 to ptr
  ret ptr %13
}

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" }

!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 = !{!"long", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}


; 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"

@sbrk.heap_end = external hidden local_unnamed_addr global i64, align 8
@_end = external global [0 x i8], align 1

; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(readwrite, argmem: none, inaccessiblemem: none) uwtable
define dso_local nonnull ptr @sbrk(i64 noundef %0) local_unnamed_addr #0 {
  %2 = load i64, ptr @sbrk.heap_end, align 8, !tbaa !5
  %3 = icmp eq i64 %2, 0
  %spec.select = select i1 %3, i64 ptrtoint (ptr @_end to i64), i64 %2
  %4 = add i64 %spec.select, %0
  store i64 %4, ptr @sbrk.heap_end, align 8, !tbaa !5
  %5 = inttoptr i64 %spec.select to ptr
  ret ptr %5
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(readwrite, argmem: none, 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 = !{!"long", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}


; Effective O3 passes: DSEPass,EarlyCSEPass,GVNPass,GlobalOptPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass