; LLVM IR from eyangch/competitive-programming :: Codeforces/981/a.ll (Z13is_palindromexx)

; 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"

%"class.std::__cxx11::basic_string" = type { %"struct.std::__cxx11::basic_string<char>::_Alloc_hider", i64, %union.anon }
%"struct.std::__cxx11::basic_string<char>::_Alloc_hider" = type { ptr }
%union.anon = type { i64, [8 x i8] }

@_Z1SB5cxx11 = external dso_local global %"class.std::__cxx11::basic_string", align 8

; Function Attrs: mustprogress uwtable
define dso_local noundef zeroext i1 @_Z13is_palindromexx(i64 noundef %0, i64 noundef %1) #0 {
  %3 = alloca i1, align 1
  %4 = alloca i64, align 8
  %5 = alloca i64, align 8
  store i64 %0, ptr %4, align 8, !tbaa !5
  store i64 %1, ptr %5, align 8, !tbaa !5
  %6 = load i64, ptr %5, align 8, !tbaa !5
  %7 = load i64, ptr %4, align 8, !tbaa !5
  %8 = icmp slt i64 %6, %7
  br i1 %8, label %9, label %10

9:                                                ; preds = %2
  store i1 true, ptr %3, align 1
  br label %27

10:                                               ; preds = %2
  %11 = load i64, ptr %4, align 8, !tbaa !5
  %12 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) @_Z1SB5cxx11, i64 noundef %11)
  %13 = load i8, ptr %12, align 1, !tbaa !9
  %14 = sext i8 %13 to i32
  %15 = load i64, ptr %5, align 8, !tbaa !5
  %16 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) @_Z1SB5cxx11, i64 noundef %15)
  %17 = load i8, ptr %16, align 1, !tbaa !9
  %18 = sext i8 %17 to i32
  %19 = icmp ne i32 %14, %18
  br i1 %19, label %20, label %21

20:                                               ; preds = %10
  store i1 false, ptr %3, align 1
  br label %27

21:                                               ; preds = %10
  %22 = load i64, ptr %4, align 8, !tbaa !5
  %23 = add nsw i64 %22, 1
  %24 = load i64, ptr %5, align 8, !tbaa !5
  %25 = sub nsw i64 %24, 1
  %26 = call noundef zeroext i1 @_Z13is_palindromexx(i64 noundef %23, i64 noundef %25)
  store i1 %26, ptr %3, align 1
  br label %27

27:                                               ; preds = %21, %20, %9
  %28 = load i1, ptr %3, align 1
  ret i1 %28
}

; Function Attrs: mustprogress nounwind uwtable
declare noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32), i64 noundef) #1 align 2

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" }
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" }

!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 = !{!"long long", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!7, !7, i64 0}


; 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"

%"class.std::__cxx11::basic_string" = type { %"struct.std::__cxx11::basic_string<char>::_Alloc_hider", i64, %union.anon }
%"struct.std::__cxx11::basic_string<char>::_Alloc_hider" = type { ptr }
%union.anon = type { i64, [8 x i8] }

@_Z1SB5cxx11 = external dso_local global %"class.std::__cxx11::basic_string", align 8

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef zeroext i1 @_Z13is_palindromexx(i64 noundef %0, i64 noundef %1) local_unnamed_addr #0 {
  %3 = icmp slt i64 %1, %0
  br i1 %3, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %2, %tailrecurse
  %.tr810 = phi i64 [ %9, %tailrecurse ], [ %1, %2 ]
  %.tr9 = phi i64 [ %8, %tailrecurse ], [ %0, %2 ]
  %4 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) @_Z1SB5cxx11, i64 noundef %.tr9)
  %5 = load i8, ptr %4, align 1, !tbaa !5
  %6 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) @_Z1SB5cxx11, i64 noundef %.tr810)
  %7 = load i8, ptr %6, align 1, !tbaa !5
  %.not = icmp eq i8 %5, %7
  br i1 %.not, label %tailrecurse, label %._crit_edge

tailrecurse:                                      ; preds = %.lr.ph
  %8 = add nsw i64 %.tr9, 1
  %9 = add nsw i64 %.tr810, -1
  %.not12 = icmp sgt i64 %.tr810, %8
  br i1 %.not12, label %.lr.ph, label %._crit_edge

._crit_edge:                                      ; preds = %tailrecurse, %.lr.ph, %2
  %.0 = phi i1 [ true, %2 ], [ %.not, %.lr.ph ], [ %.not, %tailrecurse ]
  ret i1 %.0
}

; Function Attrs: mustprogress nounwind uwtable
declare noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32), i64 noundef) local_unnamed_addr #0 align 2

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" }

!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 = !{!"omnipotent char", !7, i64 0}
!7 = !{!"Simple C++ TBAA"}


; Effective O3 passes: CorrelatedValuePropagationPass,GlobalOptPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass