; LLVM IR from Lodour/ACM-CheatSheet :: src/7_动态规划/1_子序列/1_最大子序列和.ll (Z9MaxSeqSumPii)

; 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 nounwind uwtable
define dso_local noundef i32 @_Z9MaxSeqSumPii(ptr noundef %0, i32 noundef %1) #0 {
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  store i32 %1, ptr %4, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #2
  store i32 0, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #2
  store i32 0, ptr %6, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #2
  store i32 0, ptr %7, align 4, !tbaa !9
  br label %8

8:                                                ; preds = %37, %2
  %9 = load i32, ptr %7, align 4, !tbaa !9
  %10 = load i32, ptr %4, align 4, !tbaa !9
  %11 = icmp slt i32 %9, %10
  br i1 %11, label %13, label %12

12:                                               ; preds = %8
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #2
  br label %40

13:                                               ; preds = %8
  %14 = load ptr, ptr %3, align 8, !tbaa !5
  %15 = load i32, ptr %7, align 4, !tbaa !9
  %16 = sext i32 %15 to i64
  %17 = getelementptr inbounds i32, ptr %14, i64 %16
  %18 = load i32, ptr %17, align 4, !tbaa !9
  %19 = load i32, ptr %6, align 4, !tbaa !9
  %20 = add nsw i32 %19, %18
  store i32 %20, ptr %6, align 4, !tbaa !9
  %21 = load i32, ptr %5, align 4, !tbaa !9
  %22 = load i32, ptr %6, align 4, !tbaa !9
  %23 = icmp slt i32 %21, %22
  br i1 %23, label %24, label %26

24:                                               ; preds = %13
  %25 = load i32, ptr %6, align 4, !tbaa !9
  br label %28

26:                                               ; preds = %13
  %27 = load i32, ptr %5, align 4, !tbaa !9
  br label %28

28:                                               ; preds = %26, %24
  %29 = phi i32 [ %25, %24 ], [ %27, %26 ]
  store i32 %29, ptr %5, align 4, !tbaa !9
  %30 = load i32, ptr %6, align 4, !tbaa !9
  %31 = icmp slt i32 %30, 0
  br i1 %31, label %32, label %33

32:                                               ; preds = %28
  br label %35

33:                                               ; preds = %28
  %34 = load i32, ptr %6, align 4, !tbaa !9
  br label %35

35:                                               ; preds = %33, %32
  %36 = phi i32 [ 0, %32 ], [ %34, %33 ]
  store i32 %36, ptr %6, align 4, !tbaa !9
  br label %37

37:                                               ; preds = %35
  %38 = load i32, ptr %7, align 4, !tbaa !9
  %39 = add nsw i32 %38, 1
  store i32 %39, ptr %7, align 4, !tbaa !9
  br label %8, !llvm.loop !11

40:                                               ; preds = %12
  %41 = load i32, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #2
  ret i32 %41
}

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

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

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" }
attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"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(argmem: read) uwtable
define dso_local noundef i32 @_Z9MaxSeqSumPii(ptr nocapture noundef readonly %0, i32 noundef %1) local_unnamed_addr #0 {
  %3 = icmp sgt i32 %1, 0
  br i1 %3, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %2
  %wide.trip.count = zext nneg i32 %1 to i64
  %xtraiter = and i64 %wide.trip.count, 1
  %4 = icmp eq i32 %1, 1
  br i1 %4, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i64 %wide.trip.count, 2147483646
  br label %.lr.ph

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %.lcssa.ph = phi i32 [ poison, %.lr.ph.preheader ], [ %17, %.lr.ph ]
  %indvars.iv.unr = phi i64 [ 0, %.lr.ph.preheader ], [ %indvars.iv.next.1, %.lr.ph ]
  %.01215.unr = phi i32 [ 0, %.lr.ph.preheader ], [ %18, %.lr.ph ]
  %.01314.unr = phi i32 [ 0, %.lr.ph.preheader ], [ %17, %.lr.ph ]
  %lcmp.mod.not = icmp eq i64 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %._crit_edge.loopexit.unr-lcssa
  %5 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.unr
  %6 = load i32, ptr %5, align 4, !tbaa !5
  %7 = add nsw i32 %6, %.01215.unr
  %8 = tail call i32 @llvm.smax.i32(i32 %.01314.unr, i32 %7)
  br label %._crit_edge

._crit_edge:                                      ; preds = %.lr.ph.epil, %._crit_edge.loopexit.unr-lcssa, %2
  %.013.lcssa = phi i32 [ 0, %2 ], [ %.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %8, %.lr.ph.epil ]
  ret i32 %.013.lcssa

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %indvars.iv = phi i64 [ 0, %.lr.ph.preheader.new ], [ %indvars.iv.next.1, %.lr.ph ]
  %.01215 = phi i32 [ 0, %.lr.ph.preheader.new ], [ %18, %.lr.ph ]
  %.01314 = phi i32 [ 0, %.lr.ph.preheader.new ], [ %17, %.lr.ph ]
  %niter = phi i64 [ 0, %.lr.ph.preheader.new ], [ %niter.next.1, %.lr.ph ]
  %9 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv
  %10 = load i32, ptr %9, align 4, !tbaa !5
  %11 = add nsw i32 %10, %.01215
  %12 = tail call i32 @llvm.smax.i32(i32 %.01314, i32 %11)
  %13 = tail call i32 @llvm.smax.i32(i32 %11, i32 0)
  %indvars.iv.next = or disjoint i64 %indvars.iv, 1
  %14 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next
  %15 = load i32, ptr %14, align 4, !tbaa !5
  %16 = add nsw i32 %15, %13
  %17 = tail call i32 @llvm.smax.i32(i32 %12, i32 %16)
  %18 = tail call i32 @llvm.smax.i32(i32 %16, i32 0)
  %indvars.iv.next.1 = add nuw nsw i64 %indvars.iv, 2
  %niter.next.1 = add i64 %niter, 2
  %niter.ncmp.1 = icmp eq i64 %niter.next.1, %unroll_iter
  br i1 %niter.ncmp.1, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !9
}

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i32 @llvm.smax.i32(i32, i32) #1

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read) 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 speculatable willreturn memory(none) }

!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"}


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