; LLVM IR from devparthgarg/Data-Structures-and-Algorithms :: 04. Recursion/08 Sum of N Natural Numbers/08 Sum of N Natural Numbers.ll (Z3sumi)

; 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 uwtable
define dso_local noundef i32 @_Z3sumi(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  %4 = load i32, ptr %3, align 4, !tbaa !5
  %5 = icmp eq i32 %4, 1
  br i1 %5, label %6, label %8

6:                                                ; preds = %1
  %7 = load i32, ptr %3, align 4, !tbaa !5
  store i32 %7, ptr %2, align 4
  br label %14

8:                                                ; preds = %1
  %9 = load i32, ptr %3, align 4, !tbaa !5
  %10 = load i32, ptr %3, align 4, !tbaa !5
  %11 = sub nsw i32 %10, 1
  %12 = call noundef i32 @_Z3sumi(i32 noundef %11)
  %13 = add nsw i32 %9, %12
  store i32 %13, ptr %2, align 4
  br label %14

14:                                               ; preds = %8, %6
  %15 = load i32, ptr %2, align 4
  ret i32 %15
}

attributes #0 = { mustprogress 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"}


; 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 @_Z3sumi(i32 noundef %0) local_unnamed_addr #0 {
  %2 = icmp eq i32 %0, 1
  br i1 %2, label %tailrecurse._crit_edge, label %tailrecurse.preheader

tailrecurse.preheader:                            ; preds = %1
  %3 = add i32 %0, -1
  %4 = add i32 %0, -2
  %5 = mul i32 %3, %4
  %6 = zext i32 %4 to i33
  %7 = add i32 %0, -3
  %8 = zext i32 %7 to i33
  %9 = mul i33 %6, %8
  %10 = lshr i33 %9, 1
  %11 = trunc nuw i33 %10 to i32
  %12 = add i32 %5, %0
  %13 = sub i32 %12, %11
  %14 = add nsw i32 %13, 1
  br label %tailrecurse._crit_edge

tailrecurse._crit_edge:                           ; preds = %tailrecurse.preheader, %1
  %accumulator.tr.lcssa = phi i32 [ 1, %1 ], [ %14, %tailrecurse.preheader ]
  ret i32 %accumulator.tr.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: GVNPass,GlobalOptPass,IPSCCPPass,IndVarSimplifyPass,InstCombinePass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,PostOrderFunctionAttrsPass,ReassociatePass,SCCPPass,SROAPass,SimplifyCFGPass,TailCallElimPass