; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 17. Graph (Breadth First Search)

; 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"

@rear = external dso_local global i32, align 4
@front = external dso_local global i32, align 4
@queue = external dso_local global [6 x i32], align 16

; Function Attrs: nounwind uwtable
define dso_local void @insert_q(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  %3 = load i32, ptr @front, align 4, !tbaa !5
  %4 = icmp eq i32 %3, -1
  br i1 %4, label %5, label %13

5:                                                ; preds = %1
  %6 = load i32, ptr @rear, align 4, !tbaa !5
  %7 = icmp eq i32 %6, -1
  br i1 %7, label %8, label %13

8:                                                ; preds = %5
  store i32 0, ptr @rear, align 4, !tbaa !5
  store i32 0, ptr @front, align 4, !tbaa !5
  %9 = load i32, ptr %2, align 4, !tbaa !5
  %10 = load i32, ptr @rear, align 4, !tbaa !5
  %11 = sext i32 %10 to i64
  %12 = getelementptr inbounds [6 x i32], ptr @queue, i64 0, i64 %11
  store i32 %9, ptr %12, align 4, !tbaa !5
  br label %20

13:                                               ; preds = %5, %1
  %14 = load i32, ptr @rear, align 4, !tbaa !5
  %15 = add nsw i32 %14, 1
  store i32 %15, ptr @rear, align 4, !tbaa !5
  %16 = load i32, ptr %2, align 4, !tbaa !5
  %17 = load i32, ptr @rear, align 4, !tbaa !5
  %18 = sext i32 %17 to i64
  %19 = getelementptr inbounds [6 x i32], ptr @queue, i64 0, i64 %18
  store i32 %16, ptr %19, align 4, !tbaa !5
  br label %20

20:                                               ; preds = %13, %8
  ret void
}

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 = !{!"int", !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"

@rear = external dso_local local_unnamed_addr global i32, align 4
@front = external dso_local local_unnamed_addr global i32, align 4
@queue = external dso_local local_unnamed_addr global [6 x i32], align 16

; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(readwrite, argmem: write, inaccessiblemem: none) uwtable
define dso_local void @insert_q(i32 noundef %0) local_unnamed_addr #0 {
  %2 = load i32, ptr @front, align 4, !tbaa !5
  %3 = icmp eq i32 %2, -1
  %4 = load i32, ptr @rear, align 4
  %5 = icmp eq i32 %4, -1
  %or.cond = select i1 %3, i1 %5, i1 false
  br i1 %or.cond, label %6, label %7

6:                                                ; preds = %1
  store i32 0, ptr @front, align 4, !tbaa !5
  br label %11

7:                                                ; preds = %1
  %8 = add nsw i32 %4, 1
  %9 = sext i32 %8 to i64
  %10 = getelementptr inbounds [6 x i32], ptr @queue, i64 0, i64 %9
  br label %11

11:                                               ; preds = %7, %6
  %.sink3 = phi ptr [ %10, %7 ], [ @queue, %6 ]
  %.sink = phi i32 [ %8, %7 ], [ 0, %6 ]
  store i32 %0, ptr %.sink3, align 4, !tbaa !5
  store i32 %.sink, ptr @rear, align 4
  ret void
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(readwrite, argmem: write, 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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,InstCombinePass,MergedLoadStoreMotionPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass