; LLVM IR from next-step-for-interview-prep/Coding-Ninjas-DSA-course_code_and_notes_cpp :: Milestone-2=Intro_to_C++/questions and solutions/Lec-8=Arrays (Linear_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"

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z12linearSearchPiii(ptr noundef %0, i32 noundef %1, i32 noundef %2) #0 {
  %4 = alloca i32, align 4
  %5 = alloca ptr, align 8
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  %9 = alloca i32, align 4
  %10 = alloca i32, align 4
  %11 = alloca i32, align 4
  store ptr %0, ptr %5, align 8, !tbaa !5
  store i32 %1, ptr %6, align 4, !tbaa !9
  store i32 %2, ptr %7, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %8) #2
  store i32 0, ptr %8, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %9) #2
  store i32 0, ptr %9, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %10) #2
  %12 = load i32, ptr %6, align 4, !tbaa !9
  %13 = sub nsw i32 %12, 1
  store i32 %13, ptr %10, align 4, !tbaa !9
  br label %14

14:                                               ; preds = %31, %3
  %15 = load i32, ptr %10, align 4, !tbaa !9
  %16 = icmp sge i32 %15, 0
  br i1 %16, label %18, label %17

17:                                               ; preds = %14
  call void @llvm.lifetime.end.p0(i64 4, ptr %10) #2
  br label %34

18:                                               ; preds = %14
  %19 = load ptr, ptr %5, align 8, !tbaa !5
  %20 = load i32, ptr %10, align 4, !tbaa !9
  %21 = sext i32 %20 to i64
  %22 = getelementptr inbounds i32, ptr %19, i64 %21
  %23 = load i32, ptr %22, align 4, !tbaa !9
  %24 = load i32, ptr %7, align 4, !tbaa !9
  %25 = icmp eq i32 %23, %24
  br i1 %25, label %26, label %30

26:                                               ; preds = %18
  %27 = load i32, ptr %8, align 4, !tbaa !9
  %28 = add nsw i32 %27, 1
  store i32 %28, ptr %8, align 4, !tbaa !9
  %29 = load i32, ptr %10, align 4, !tbaa !9
  store i32 %29, ptr %9, align 4, !tbaa !9
  br label %30

30:                                               ; preds = %26, %18
  br label %31

31:                                               ; preds = %30
  %32 = load i32, ptr %10, align 4, !tbaa !9
  %33 = add nsw i32 %32, -1
  store i32 %33, ptr %10, align 4, !tbaa !9
  br label %14, !llvm.loop !11

34:                                               ; preds = %17
  %35 = load i32, ptr %8, align 4, !tbaa !9
  %36 = icmp sgt i32 %35, 0
  br i1 %36, label %37, label %39

37:                                               ; preds = %34
  %38 = load i32, ptr %9, align 4, !tbaa !9
  store i32 %38, ptr %4, align 4
  store i32 1, ptr %11, align 4
  br label %40

39:                                               ; preds = %34
  store i32 -1, ptr %4, align 4
  store i32 1, ptr %11, align 4
  br label %40

40:                                               ; preds = %39, %37
  call void @llvm.lifetime.end.p0(i64 4, ptr %9) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %8) #2
  %41 = load i32, ptr %4, align 4
  ret i32 %41
}

; 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 = { 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 #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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"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: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read) uwtable
define dso_local noundef range(i32 -1, 2147483647) i32 @_Z12linearSearchPiii(ptr nocapture noundef readonly %0, i32 noundef %1, i32 noundef %2) local_unnamed_addr #0 {
  %4 = icmp sgt i32 %1, 0
  br i1 %4, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %3
  %5 = zext nneg i32 %1 to i64
  %xtraiter = and i64 %5, 3
  %6 = icmp ult i32 %1, 4
  br i1 %6, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i64 %5, 2147483644
  br label %.lr.ph

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %spec.select.lcssa.ph = phi i32 [ poison, %.lr.ph.preheader ], [ %spec.select.3, %.lr.ph ]
  %spec.select14.lcssa.ph = phi i32 [ poison, %.lr.ph.preheader ], [ %spec.select14.3, %.lr.ph ]
  %indvars.iv.unr = phi i64 [ %5, %.lr.ph.preheader ], [ %indvars.iv.next.3, %.lr.ph ]
  %.01016.unr = phi i32 [ 0, %.lr.ph.preheader ], [ %spec.select14.3, %.lr.ph ]
  %.01115.unr = phi i32 [ 0, %.lr.ph.preheader ], [ %spec.select.3, %.lr.ph ]
  %lcmp.mod.not = icmp eq i64 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge.loopexit, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil
  %indvars.iv.epil = phi i64 [ %indvars.iv.next.epil, %.lr.ph.epil ], [ %indvars.iv.unr, %._crit_edge.loopexit.unr-lcssa ]
  %.01016.epil = phi i32 [ %spec.select14.epil, %.lr.ph.epil ], [ %.01016.unr, %._crit_edge.loopexit.unr-lcssa ]
  %.01115.epil = phi i32 [ %spec.select.epil, %.lr.ph.epil ], [ %.01115.unr, %._crit_edge.loopexit.unr-lcssa ]
  %epil.iter = phi i64 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.loopexit.unr-lcssa ]
  %indvars.iv.next.epil = add nsw i64 %indvars.iv.epil, -1
  %7 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next.epil
  %8 = load i32, ptr %7, align 4, !tbaa !5
  %9 = icmp eq i32 %8, %2
  %10 = zext i1 %9 to i32
  %spec.select.epil = add nuw nsw i32 %.01115.epil, %10
  %11 = trunc nuw nsw i64 %indvars.iv.next.epil to i32
  %spec.select14.epil = select i1 %9, i32 %11, i32 %.01016.epil
  %epil.iter.next = add i64 %epil.iter, 1
  %epil.iter.cmp.not = icmp eq i64 %epil.iter.next, %xtraiter
  br i1 %epil.iter.cmp.not, label %._crit_edge.loopexit, label %.lr.ph.epil, !llvm.loop !9

._crit_edge.loopexit:                             ; preds = %.lr.ph.epil, %._crit_edge.loopexit.unr-lcssa
  %spec.select.lcssa = phi i32 [ %spec.select.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %spec.select.epil, %.lr.ph.epil ]
  %spec.select14.lcssa = phi i32 [ %spec.select14.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %spec.select14.epil, %.lr.ph.epil ]
  %.not = icmp eq i32 %spec.select.lcssa, 0
  %12 = select i1 %.not, i32 -1, i32 %spec.select14.lcssa
  br label %._crit_edge

._crit_edge:                                      ; preds = %._crit_edge.loopexit, %3
  %.011.lcssa = phi i32 [ -1, %3 ], [ %12, %._crit_edge.loopexit ]
  ret i32 %.011.lcssa

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %indvars.iv = phi i64 [ %5, %.lr.ph.preheader.new ], [ %indvars.iv.next.3, %.lr.ph ]
  %.01016 = phi i32 [ 0, %.lr.ph.preheader.new ], [ %spec.select14.3, %.lr.ph ]
  %.01115 = phi i32 [ 0, %.lr.ph.preheader.new ], [ %spec.select.3, %.lr.ph ]
  %niter = phi i64 [ 0, %.lr.ph.preheader.new ], [ %niter.next.3, %.lr.ph ]
  %indvars.iv.next = add nsw i64 %indvars.iv, -1
  %13 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next
  %14 = load i32, ptr %13, align 4, !tbaa !5
  %15 = icmp eq i32 %14, %2
  %16 = zext i1 %15 to i32
  %spec.select = add nuw nsw i32 %.01115, %16
  %17 = trunc nuw nsw i64 %indvars.iv.next to i32
  %spec.select14 = select i1 %15, i32 %17, i32 %.01016
  %indvars.iv.next.1 = add nsw i64 %indvars.iv, -2
  %18 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next.1
  %19 = load i32, ptr %18, align 4, !tbaa !5
  %20 = icmp eq i32 %19, %2
  %21 = zext i1 %20 to i32
  %spec.select.1 = add nuw nsw i32 %spec.select, %21
  %22 = trunc nuw nsw i64 %indvars.iv.next.1 to i32
  %spec.select14.1 = select i1 %20, i32 %22, i32 %spec.select14
  %indvars.iv.next.2 = add nsw i64 %indvars.iv, -3
  %23 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next.2
  %24 = load i32, ptr %23, align 4, !tbaa !5
  %25 = icmp eq i32 %24, %2
  %26 = zext i1 %25 to i32
  %spec.select.2 = add nuw nsw i32 %spec.select.1, %26
  %27 = trunc nuw nsw i64 %indvars.iv.next.2 to i32
  %spec.select14.2 = select i1 %25, i32 %27, i32 %spec.select14.1
  %indvars.iv.next.3 = add nsw i64 %indvars.iv, -4
  %28 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next.3
  %29 = load i32, ptr %28, align 4, !tbaa !5
  %30 = icmp eq i32 %29, %2
  %31 = zext i1 %30 to i32
  %spec.select.3 = add nuw nsw i32 %spec.select.2, %31
  %32 = trunc nuw nsw i64 %indvars.iv.next.3 to i32
  %spec.select14.3 = select i1 %30, i32 %32, i32 %spec.select14.2
  %niter.next.3 = add i64 %niter, 4
  %niter.ncmp.3.not = icmp eq i64 %niter.next.3, %unroll_iter
  br i1 %niter.ncmp.3.not, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !11
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read) 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++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.unroll.disable"}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


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