; LLVM IR from devparthgarg/Data-Structures-and-Algorithms :: 01. Time and Space Analysis/01 Need of Asymptotic Analysis/code.ll (Z4sum2i)

; 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: 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 @_Z4sum2i(i32 noundef %0) #1 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #2
  store i32 0, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  store i32 1, ptr %4, align 4, !tbaa !5
  br label %5

5:                                                ; preds = %14, %1
  %6 = load i32, ptr %4, align 4, !tbaa !5
  %7 = load i32, ptr %2, align 4, !tbaa !5
  %8 = icmp sle i32 %6, %7
  br i1 %8, label %10, label %9

9:                                                ; preds = %5
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  br label %17

10:                                               ; preds = %5
  %11 = load i32, ptr %4, align 4, !tbaa !5
  %12 = load i32, ptr %3, align 4, !tbaa !5
  %13 = add nsw i32 %12, %11
  store i32 %13, ptr %3, align 4, !tbaa !5
  br label %14

14:                                               ; preds = %10
  %15 = load i32, ptr %4, align 4, !tbaa !5
  %16 = add nsw i32 %15, 1
  store i32 %16, ptr %4, align 4, !tbaa !5
  br label %5, !llvm.loop !9

17:                                               ; preds = %9
  %18 = load i32, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #2
  ret i32 %18
}

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 = distinct !{!9, !10}
!10 = !{!"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(none) uwtable
define dso_local noundef i32 @_Z4sum2i(i32 noundef %0) local_unnamed_addr #0 {
  %.not7 = icmp slt i32 %0, 1
  br i1 %.not7, label %._crit_edge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %1
  %2 = shl nuw i32 %0, 1
  %3 = add nsw i32 %0, -1
  %4 = zext nneg i32 %3 to i33
  %5 = add nsw i32 %0, -2
  %6 = zext i32 %5 to i33
  %7 = mul i33 %4, %6
  %8 = lshr i33 %7, 1
  %9 = trunc nuw i33 %8 to i32
  %10 = add i32 %2, %9
  %11 = add i32 %10, -1
  br label %._crit_edge

._crit_edge:                                      ; preds = %.lr.ph.preheader, %1
  %.06.lcssa = phi i32 [ 0, %1 ], [ %11, %.lr.ph.preheader ]
  ret i32 %.06.lcssa
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(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)"}


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