; LLVM IR from upupming/algorithm :: CCCC-GPLT/L1-013. 计算阶乘和 (main)

; 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::basic_istream" = type { ptr, i64, %"class.std::basic_ios" }
%"class.std::basic_ios" = type { %"class.std::ios_base", ptr, i8, i8, ptr, ptr, ptr, ptr }
%"class.std::ios_base" = type { ptr, i64, i64, i32, i32, i32, ptr, %"struct.std::ios_base::_Words", [8 x %"struct.std::ios_base::_Words"], i32, ptr, %"class.std::locale" }
%"struct.std::ios_base::_Words" = type { ptr, i64 }
%"class.std::locale" = type { ptr }
%"class.std::basic_ostream" = type { ptr, %"class.std::basic_ios" }

@_ZSt3cin = external global %"class.std::basic_istream", align 8
@_ZSt4cout = external global %"class.std::basic_ostream", align 8

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() #0 {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  store i32 0, ptr %1, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr %2) #3
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #3
  store i32 0, ptr %3, align 4, !tbaa !5
  %8 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %2)
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #3
  store i32 1, ptr %4, align 4, !tbaa !5
  br label %9

9:                                                ; preds = %31, %0
  %10 = load i32, ptr %4, align 4, !tbaa !5
  %11 = load i32, ptr %2, align 4, !tbaa !5
  %12 = icmp sle i32 %10, %11
  br i1 %12, label %14, label %13

13:                                               ; preds = %9
  store i32 2, ptr %5, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #3
  br label %34

14:                                               ; preds = %9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #3
  store i32 1, ptr %6, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #3
  store i32 1, ptr %7, align 4, !tbaa !5
  br label %15

15:                                               ; preds = %24, %14
  %16 = load i32, ptr %7, align 4, !tbaa !5
  %17 = load i32, ptr %4, align 4, !tbaa !5
  %18 = icmp sle i32 %16, %17
  br i1 %18, label %20, label %19

19:                                               ; preds = %15
  store i32 5, ptr %5, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #3
  br label %27

20:                                               ; preds = %15
  %21 = load i32, ptr %7, align 4, !tbaa !5
  %22 = load i32, ptr %6, align 4, !tbaa !5
  %23 = mul nsw i32 %22, %21
  store i32 %23, ptr %6, align 4, !tbaa !5
  br label %24

24:                                               ; preds = %20
  %25 = load i32, ptr %7, align 4, !tbaa !5
  %26 = add nsw i32 %25, 1
  store i32 %26, ptr %7, align 4, !tbaa !5
  br label %15, !llvm.loop !9

27:                                               ; preds = %19
  %28 = load i32, ptr %6, align 4, !tbaa !5
  %29 = load i32, ptr %3, align 4, !tbaa !5
  %30 = add nsw i32 %29, %28
  store i32 %30, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #3
  br label %31

31:                                               ; preds = %27
  %32 = load i32, ptr %4, align 4, !tbaa !5
  %33 = add nsw i32 %32, 1
  store i32 %33, ptr %4, align 4, !tbaa !5
  br label %9, !llvm.loop !11

34:                                               ; preds = %13
  %35 = load i32, ptr %3, align 4, !tbaa !5
  %36 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, i32 noundef %35)
  store i32 0, ptr %1, align 4
  store i32 1, ptr %5, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %2) #3
  %37 = load i32, ptr %1, align 4
  ret i32 %37
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

declare noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16), ptr noundef nonnull align 4 dereferenceable(4)) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #1

declare noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8), i32 noundef) #2

attributes #0 = { mustprogress norecurse 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 = { "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 #3 = { 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"}
!11 = distinct !{!11, !10}


; 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::basic_istream" = type { ptr, i64, %"class.std::basic_ios" }
%"class.std::basic_ios" = type { %"class.std::ios_base", ptr, i8, i8, ptr, ptr, ptr, ptr }
%"class.std::ios_base" = type { ptr, i64, i64, i32, i32, i32, ptr, %"struct.std::ios_base::_Words", [8 x %"struct.std::ios_base::_Words"], i32, ptr, %"class.std::locale" }
%"struct.std::ios_base::_Words" = type { ptr, i64 }
%"class.std::locale" = type { ptr }
%"class.std::basic_ostream" = type { ptr, %"class.std::basic_ios" }

@_ZSt3cin = external global %"class.std::basic_istream", align 8
@_ZSt4cout = external global %"class.std::basic_ostream", align 8

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() local_unnamed_addr #0 {
  %1 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %1) #4
  %2 = call noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16) @_ZSt3cin, ptr noundef nonnull align 4 dereferenceable(4) %1)
  %3 = load i32, ptr %1, align 4, !tbaa !5
  %.not17 = icmp slt i32 %3, 1
  br i1 %.not17, label %._crit_edge, label %.preheader.preheader

.preheader.preheader:                             ; preds = %0
  %4 = add nuw i32 %3, 1
  br label %.preheader

.preheader:                                       ; preds = %.preheader.preheader, %.loopexit
  %indvar = phi i32 [ 0, %.preheader.preheader ], [ %indvar.next, %.loopexit ]
  %indvars.iv = phi i32 [ 2, %.preheader.preheader ], [ %indvars.iv.next, %.loopexit ]
  %.01318 = phi i32 [ 0, %.preheader.preheader ], [ %11, %.loopexit ]
  %5 = add i32 %indvar, 1
  %min.iters.check = icmp ult i32 %5, 8
  br i1 %min.iters.check, label %scalar.ph.preheader, label %vector.ph

scalar.ph.preheader:                              ; preds = %middle.block, %.preheader
  %.016.ph = phi i32 [ 1, %.preheader ], [ %ind.end, %middle.block ]
  %.01115.ph = phi i32 [ 1, %.preheader ], [ %9, %middle.block ]
  br label %scalar.ph

vector.ph:                                        ; preds = %.preheader
  %n.vec = and i32 %5, -8
  %ind.end = or disjoint i32 %n.vec, 1
  br label %vector.body

vector.body:                                      ; preds = %vector.body, %vector.ph
  %index = phi i32 [ 0, %vector.ph ], [ %index.next, %vector.body ]
  %vec.ind = phi <4 x i32> [ <i32 1, i32 2, i32 3, i32 4>, %vector.ph ], [ %vec.ind.next, %vector.body ]
  %vec.phi = phi <4 x i32> [ <i32 1, i32 1, i32 1, i32 1>, %vector.ph ], [ %6, %vector.body ]
  %vec.phi25 = phi <4 x i32> [ <i32 1, i32 1, i32 1, i32 1>, %vector.ph ], [ %7, %vector.body ]
  %step.add = add <4 x i32> %vec.ind, <i32 4, i32 4, i32 4, i32 4>
  %6 = mul <4 x i32> %vec.ind, %vec.phi
  %7 = mul <4 x i32> %step.add, %vec.phi25
  %index.next = add nuw i32 %index, 8
  %vec.ind.next = add <4 x i32> %vec.ind, <i32 8, i32 8, i32 8, i32 8>
  %8 = icmp eq i32 %index.next, %n.vec
  br i1 %8, label %middle.block, label %vector.body, !llvm.loop !9

middle.block:                                     ; preds = %vector.body
  %bin.rdx = mul <4 x i32> %7, %6
  %9 = call i32 @llvm.vector.reduce.mul.v4i32(<4 x i32> %bin.rdx)
  %cmp.n = icmp eq i32 %5, %n.vec
  br i1 %cmp.n, label %.loopexit, label %scalar.ph.preheader

._crit_edge:                                      ; preds = %.loopexit, %0
  %.013.lcssa = phi i32 [ 0, %0 ], [ %11, %.loopexit ]
  %10 = call noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8) @_ZSt4cout, i32 noundef %.013.lcssa)
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %1) #4
  ret i32 0

.loopexit:                                        ; preds = %scalar.ph, %middle.block
  %.lcssa = phi i32 [ %9, %middle.block ], [ %12, %scalar.ph ]
  %11 = add nuw nsw i32 %.lcssa, %.01318
  %indvars.iv.next = add nuw i32 %indvars.iv, 1
  %exitcond21.not = icmp eq i32 %indvars.iv, %4
  %indvar.next = add i32 %indvar, 1
  br i1 %exitcond21.not, label %._crit_edge, label %.preheader, !llvm.loop !13

scalar.ph:                                        ; preds = %scalar.ph.preheader, %scalar.ph
  %.016 = phi i32 [ %13, %scalar.ph ], [ %.016.ph, %scalar.ph.preheader ]
  %.01115 = phi i32 [ %12, %scalar.ph ], [ %.01115.ph, %scalar.ph.preheader ]
  %12 = mul nuw nsw i32 %.016, %.01115
  %13 = add nuw i32 %.016, 1
  %exitcond.not = icmp eq i32 %13, %indvars.iv
  br i1 %exitcond.not, label %.loopexit, label %scalar.ph, !llvm.loop !14
}

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

declare noundef nonnull align 8 dereferenceable(16) ptr @_ZNSirsERi(ptr noundef nonnull align 8 dereferenceable(16), ptr noundef nonnull align 4 dereferenceable(4)) local_unnamed_addr #2

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #1

declare noundef nonnull align 8 dereferenceable(8) ptr @_ZNSolsEi(ptr noundef nonnull align 8 dereferenceable(8), i32 noundef) local_unnamed_addr #2

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i32 @llvm.vector.reduce.mul.v4i32(<4 x i32>) #3

attributes #0 = { mustprogress norecurse 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 nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { "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 #3 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
attributes #4 = { 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, !11, !12}
!10 = !{!"llvm.loop.mustprogress"}
!11 = !{!"llvm.loop.isvectorized", i32 1}
!12 = !{!"llvm.loop.unroll.runtime.disable"}
!13 = distinct !{!13, !10}
!14 = distinct !{!14, !10, !12, !11}


; Effective O3 passes: GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LICMPass,LoopLoadEliminationPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,LoopVectorizePass,ReassociatePass,SROAPass,SimplifyCFGPass