; LLVM IR from gzc/CLRS :: C32-String-Matching (KMP)

; 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: nounwind uwtable
define dso_local ptr @compute_prefix_function(ptr noundef %0) #0 {
  %2 = alloca ptr, align 8
  %3 = alloca i32, align 4
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #4
  %7 = load ptr, ptr %2, align 8, !tbaa !5
  %8 = call i64 @strlen(ptr noundef %7) #5
  %9 = trunc i64 %8 to i32
  store i32 %9, ptr %3, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #4
  %10 = load i32, ptr %3, align 4, !tbaa !9
  %11 = sext i32 %10 to i64
  %12 = mul i64 %11, 4
  %13 = call noalias ptr @malloc(i64 noundef %12) #6
  store ptr %13, ptr %4, align 8, !tbaa !5
  %14 = load ptr, ptr %4, align 8, !tbaa !5
  %15 = getelementptr inbounds i32, ptr %14, i64 0
  store i32 0, ptr %15, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #4
  store i32 0, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #4
  store i32 1, ptr %6, align 4, !tbaa !9
  br label %16

16:                                               ; preds = %70, %1
  %17 = load i32, ptr %6, align 4, !tbaa !9
  %18 = load i32, ptr %3, align 4, !tbaa !9
  %19 = icmp slt i32 %17, %18
  br i1 %19, label %20, label %73

20:                                               ; preds = %16
  br label %21

21:                                               ; preds = %40, %20
  %22 = load i32, ptr %5, align 4, !tbaa !9
  %23 = icmp sgt i32 %22, 0
  br i1 %23, label %24, label %38

24:                                               ; preds = %21
  %25 = load ptr, ptr %2, align 8, !tbaa !5
  %26 = load i32, ptr %5, align 4, !tbaa !9
  %27 = sext i32 %26 to i64
  %28 = getelementptr inbounds i8, ptr %25, i64 %27
  %29 = load i8, ptr %28, align 1, !tbaa !11
  %30 = sext i8 %29 to i32
  %31 = load ptr, ptr %2, align 8, !tbaa !5
  %32 = load i32, ptr %6, align 4, !tbaa !9
  %33 = sext i32 %32 to i64
  %34 = getelementptr inbounds i8, ptr %31, i64 %33
  %35 = load i8, ptr %34, align 1, !tbaa !11
  %36 = sext i8 %35 to i32
  %37 = icmp ne i32 %30, %36
  br label %38

38:                                               ; preds = %24, %21
  %39 = phi i1 [ false, %21 ], [ %37, %24 ]
  br i1 %39, label %40, label %47

40:                                               ; preds = %38
  %41 = load ptr, ptr %4, align 8, !tbaa !5
  %42 = load i32, ptr %5, align 4, !tbaa !9
  %43 = sub nsw i32 %42, 1
  %44 = sext i32 %43 to i64
  %45 = getelementptr inbounds i32, ptr %41, i64 %44
  %46 = load i32, ptr %45, align 4, !tbaa !9
  store i32 %46, ptr %5, align 4, !tbaa !9
  br label %21, !llvm.loop !12

47:                                               ; preds = %38
  %48 = load ptr, ptr %2, align 8, !tbaa !5
  %49 = load i32, ptr %5, align 4, !tbaa !9
  %50 = sext i32 %49 to i64
  %51 = getelementptr inbounds i8, ptr %48, i64 %50
  %52 = load i8, ptr %51, align 1, !tbaa !11
  %53 = sext i8 %52 to i32
  %54 = load ptr, ptr %2, align 8, !tbaa !5
  %55 = load i32, ptr %6, align 4, !tbaa !9
  %56 = sext i32 %55 to i64
  %57 = getelementptr inbounds i8, ptr %54, i64 %56
  %58 = load i8, ptr %57, align 1, !tbaa !11
  %59 = sext i8 %58 to i32
  %60 = icmp eq i32 %53, %59
  br i1 %60, label %61, label %64

61:                                               ; preds = %47
  %62 = load i32, ptr %5, align 4, !tbaa !9
  %63 = add nsw i32 %62, 1
  store i32 %63, ptr %5, align 4, !tbaa !9
  br label %64

64:                                               ; preds = %61, %47
  %65 = load i32, ptr %5, align 4, !tbaa !9
  %66 = load ptr, ptr %4, align 8, !tbaa !5
  %67 = load i32, ptr %6, align 4, !tbaa !9
  %68 = sext i32 %67 to i64
  %69 = getelementptr inbounds i32, ptr %66, i64 %68
  store i32 %65, ptr %69, align 4, !tbaa !9
  br label %70

70:                                               ; preds = %64
  %71 = load i32, ptr %6, align 4, !tbaa !9
  %72 = add nsw i32 %71, 1
  store i32 %72, ptr %6, align 4, !tbaa !9
  br label %16, !llvm.loop !14

73:                                               ; preds = %16
  %74 = load ptr, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #4
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #4
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #4
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #4
  ret ptr %74
}

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

; Function Attrs: nounwind willreturn memory(read)
declare i64 @strlen(ptr noundef) #2

; Function Attrs: nounwind allocsize(0)
declare noalias ptr @malloc(i64 noundef) #3

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

attributes #0 = { 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 willreturn memory(read) "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 allocsize(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 #4 = { nounwind }
attributes #5 = { nounwind willreturn memory(read) }
attributes #6 = { nounwind allocsize(0) }

!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"}
!14 = distinct !{!14, !13}


; 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 nounwind memory(readwrite, argmem: read) uwtable
define dso_local noalias noundef ptr @compute_prefix_function(ptr nocapture noundef readonly %0) local_unnamed_addr #0 {
  %2 = tail call i64 @strlen(ptr noundef nonnull dereferenceable(1) %0) #3
  %3 = trunc i64 %2 to i32
  %sext = shl i64 %2, 32
  %4 = ashr exact i64 %sext, 30
  %5 = tail call noalias ptr @malloc(i64 noundef %4) #4
  store i32 0, ptr %5, align 4, !tbaa !5
  %6 = icmp sgt i32 %3, 1
  br i1 %6, label %.preheader.lr.ph, label %._crit_edge

.preheader.lr.ph:                                 ; preds = %1
  %invariant.gep = getelementptr i8, ptr %5, i64 -4
  %wide.trip.count = and i64 %2, 2147483647
  br label %.preheader

.preheader:                                       ; preds = %.preheader.lr.ph, %.critedge
  %indvars.iv = phi i64 [ 1, %.preheader.lr.ph ], [ %indvars.iv.next, %.critedge ]
  %.02125 = phi i32 [ 0, %.preheader.lr.ph ], [ %spec.select, %.critedge ]
  %7 = icmp sgt i32 %.02125, 0
  %8 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv
  %9 = load i8, ptr %8, align 1, !tbaa !9
  br i1 %7, label %.lr.ph, label %.critedge

.lr.ph:                                           ; preds = %.preheader, %13
  %.122 = phi i32 [ %14, %13 ], [ %.02125, %.preheader ]
  %10 = zext nneg i32 %.122 to i64
  %11 = getelementptr inbounds i8, ptr %0, i64 %10
  %12 = load i8, ptr %11, align 1, !tbaa !9
  %.not = icmp eq i8 %12, %9
  br i1 %.not, label %.critedge, label %13

13:                                               ; preds = %.lr.ph
  %gep = getelementptr i32, ptr %invariant.gep, i64 %10
  %14 = load i32, ptr %gep, align 4, !tbaa !5
  %15 = icmp sgt i32 %14, 0
  br i1 %15, label %.lr.ph, label %.critedge, !llvm.loop !10

.critedge:                                        ; preds = %.lr.ph, %13, %.preheader
  %.1.lcssa = phi i32 [ %.02125, %.preheader ], [ %14, %13 ], [ %.122, %.lr.ph ]
  %16 = sext i32 %.1.lcssa to i64
  %17 = getelementptr inbounds i8, ptr %0, i64 %16
  %18 = load i8, ptr %17, align 1, !tbaa !9
  %19 = icmp eq i8 %18, %9
  %20 = zext i1 %19 to i32
  %spec.select = add nsw i32 %.1.lcssa, %20
  %21 = getelementptr inbounds i32, ptr %5, i64 %indvars.iv
  store i32 %spec.select, ptr %21, align 4, !tbaa !5
  %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 %._crit_edge, label %.preheader, !llvm.loop !12

._crit_edge:                                      ; preds = %.critedge, %1
  ret ptr %5
}

; Function Attrs: mustprogress nofree nounwind willreturn memory(argmem: read)
declare i64 @strlen(ptr nocapture noundef) local_unnamed_addr #1

; Function Attrs: mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(inaccessiblemem: readwrite)
declare noalias noundef ptr @malloc(i64 noundef) local_unnamed_addr #2

attributes #0 = { nofree nounwind memory(readwrite, 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 = { mustprogress nofree nounwind willreturn memory(argmem: read) "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 = { mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(inaccessiblemem: readwrite) "alloc-family"="malloc" "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 willreturn memory(read) }
attributes #4 = { nounwind allocsize(0) }

!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/C++ TBAA"}
!9 = !{!7, !7, i64 0}
!10 = distinct !{!10, !11}
!11 = !{!"llvm.loop.mustprogress"}
!12 = distinct !{!12, !11}


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