; LLVM IR from Lakhankumawat/LearnCPP :: R-Recursion/Types of Recursion/DirectRecursion.ll (Z6squarei)

; 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 @_Z6squarei(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, 0
  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 %16

8:                                                ; preds = %1
  %9 = load i32, ptr %3, align 4, !tbaa !5
  %10 = sub nsw i32 %9, 1
  %11 = call noundef i32 @_Z6squarei(i32 noundef %10)
  %12 = load i32, ptr %3, align 4, !tbaa !5
  %13 = mul nsw i32 2, %12
  %14 = add nsw i32 %11, %13
  %15 = sub nsw i32 %14, 1
  store i32 %15, ptr %2, align 4
  br label %16

16:                                               ; preds = %8, %6
  %17 = load i32, ptr %2, align 4
  ret i32 %17
}

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 nosync nounwind willreturn memory(none) uwtable
define dso_local noundef range(i32 -2147483648, 2147483647) i32 @_Z6squarei(i32 noundef %0) local_unnamed_addr #0 {
  br label %tailrecurse

tailrecurse:                                      ; preds = %3, %1
  %accumulator.tr = phi i32 [ 0, %1 ], [ %7, %3 ]
  %.tr = phi i32 [ %0, %1 ], [ %4, %3 ]
  %2 = icmp eq i32 %.tr, 0
  br i1 %2, label %common.ret, label %3

common.ret:                                       ; preds = %tailrecurse
  %accumulator.ret.tr = add i32 0, %accumulator.tr
  ret i32 %accumulator.ret.tr

3:                                                ; preds = %tailrecurse
  %4 = add nsw i32 %.tr, -1
  %5 = shl nsw i32 %.tr, 1
  %6 = add i32 %5, -1
  %7 = add i32 %6, %accumulator.tr
  br label %tailrecurse
}

attributes #0 = { mustprogress nofree 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: GlobalOptPass,IPSCCPPass,InstCombinePass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass