; LLVM IR from kaynewbie/algorithm :: algorithm/LeetCode/Easy (longest-common-prefix)

; 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: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nounwind uwtable
define dso_local i32 @commonPrefixLength(ptr noundef %0, i32 noundef %1, ptr noundef %2) #1 {
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  %6 = alloca ptr, align 8
  %7 = alloca i32, align 4
  store ptr %0, ptr %4, align 8, !tbaa !5
  store i32 %1, ptr %5, align 4, !tbaa !9
  store ptr %2, ptr %6, align 8, !tbaa !5
  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 = %33, %3
  %9 = load i32, ptr %7, align 4, !tbaa !9
  %10 = load i32, ptr %5, align 4, !tbaa !9
  %11 = icmp slt i32 %9, %10
  br i1 %11, label %12, label %31

12:                                               ; preds = %8
  %13 = load ptr, ptr %4, align 8, !tbaa !5
  %14 = load i8, ptr %13, align 1, !tbaa !11
  %15 = sext i8 %14 to i32
  %16 = icmp ne i32 %15, 0
  br i1 %16, label %17, label %31

17:                                               ; preds = %12
  %18 = load ptr, ptr %4, align 8, !tbaa !5
  %19 = load i32, ptr %7, align 4, !tbaa !9
  %20 = sext i32 %19 to i64
  %21 = getelementptr inbounds i8, ptr %18, i64 %20
  %22 = load i8, ptr %21, align 1, !tbaa !11
  %23 = sext i8 %22 to i32
  %24 = load ptr, ptr %6, align 8, !tbaa !5
  %25 = load i32, ptr %7, align 4, !tbaa !9
  %26 = sext i32 %25 to i64
  %27 = getelementptr inbounds i8, ptr %24, i64 %26
  %28 = load i8, ptr %27, align 1, !tbaa !11
  %29 = sext i8 %28 to i32
  %30 = icmp eq i32 %23, %29
  br label %31

31:                                               ; preds = %17, %12, %8
  %32 = phi i1 [ false, %12 ], [ false, %8 ], [ %30, %17 ]
  br i1 %32, label %33, label %36

33:                                               ; preds = %31
  %34 = load i32, ptr %7, align 4, !tbaa !9
  %35 = add nsw i32 %34, 1
  store i32 %35, ptr %7, align 4, !tbaa !9
  br label %8, !llvm.loop !12

36:                                               ; preds = %31
  %37 = load i32, ptr %7, align 4, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #2
  ret i32 %37
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #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/C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = !{!7, !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"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: nofree norecurse nosync nounwind memory(argmem: read) uwtable
define dso_local i32 @commonPrefixLength(ptr nocapture noundef readonly %0, i32 noundef %1, ptr nocapture noundef readonly %2) local_unnamed_addr #0 {
  %4 = icmp sgt i32 %1, 0
  br i1 %4, label %.lr.ph, label %.critedge

.lr.ph:                                           ; preds = %3
  %5 = load i8, ptr %0, align 1, !tbaa !5
  %.not = icmp eq i8 %5, 0
  br i1 %.not, label %.critedge, label %.lr.ph.split.preheader

.lr.ph.split.preheader:                           ; preds = %.lr.ph
  %wide.trip.count = zext nneg i32 %1 to i64
  br label %.lr.ph.split

.lr.ph.split:                                     ; preds = %.lr.ph.split.preheader, %11
  %indvars.iv = phi i64 [ 0, %.lr.ph.split.preheader ], [ %indvars.iv.next, %11 ]
  %6 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv
  %7 = load i8, ptr %6, align 1, !tbaa !5
  %8 = getelementptr inbounds i8, ptr %2, i64 %indvars.iv
  %9 = load i8, ptr %8, align 1, !tbaa !5
  %10 = icmp eq i8 %7, %9
  br i1 %10, label %11, label %.critedge.loopexit.split.loop.exit14

11:                                               ; preds = %.lr.ph.split
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %exitcond.not = icmp eq i64 %indvars.iv.next, %wide.trip.count
  br i1 %exitcond.not, label %.critedge, label %.lr.ph.split, !llvm.loop !8

.critedge.loopexit.split.loop.exit14:             ; preds = %.lr.ph.split
  %12 = trunc nuw nsw i64 %indvars.iv to i32
  br label %.critedge

.critedge:                                        ; preds = %11, %.critedge.loopexit.split.loop.exit14, %.lr.ph, %3
  %.0.lcssa = phi i32 [ 0, %3 ], [ 0, %.lr.ph ], [ %12, %.critedge.loopexit.split.loop.exit14 ], [ %1, %11 ]
  ret i32 %.0.lcssa
}

attributes #0 = { nofree norecurse nosync nounwind 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" }

!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/C++ TBAA"}
!8 = distinct !{!8, !9}
!9 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LICMPass,LoopRotatePass,LoopSimplifyCFGPass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass