; LLVM IR from 6leetcode/6leetcode :: questions/Algorithms/0089. Gray Code (c1)

; 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 @grayCode(i32 noundef %0, ptr noundef %1) #0 {
  %3 = alloca i32, align 4
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  %6 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  store ptr %1, ptr %4, align 8, !tbaa !9
  %7 = load i32, ptr %3, align 4, !tbaa !5
  %8 = sitofp i32 %7 to double
  %9 = call double @pow(double noundef 2.000000e+00, double noundef %8) #4
  %10 = fptosi double %9 to i32
  %11 = load ptr, ptr %4, align 8, !tbaa !9
  store i32 %10, ptr %11, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #4
  %12 = load ptr, ptr %4, align 8, !tbaa !9
  %13 = load i32, ptr %12, align 4, !tbaa !5
  %14 = sext i32 %13 to i64
  %15 = mul i64 4, %14
  %16 = call noalias ptr @malloc(i64 noundef %15) #5
  store ptr %16, ptr %5, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #4
  store i32 0, ptr %6, align 4, !tbaa !5
  br label %17

17:                                               ; preds = %32, %2
  %18 = load i32, ptr %6, align 4, !tbaa !5
  %19 = load ptr, ptr %4, align 8, !tbaa !9
  %20 = load i32, ptr %19, align 4, !tbaa !5
  %21 = icmp slt i32 %18, %20
  br i1 %21, label %23, label %22

22:                                               ; preds = %17
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #4
  br label %35

23:                                               ; preds = %17
  %24 = load i32, ptr %6, align 4, !tbaa !5
  %25 = ashr i32 %24, 1
  %26 = load i32, ptr %6, align 4, !tbaa !5
  %27 = xor i32 %25, %26
  %28 = load ptr, ptr %5, align 8, !tbaa !9
  %29 = load i32, ptr %6, align 4, !tbaa !5
  %30 = sext i32 %29 to i64
  %31 = getelementptr inbounds i32, ptr %28, i64 %30
  store i32 %27, ptr %31, align 4, !tbaa !5
  br label %32

32:                                               ; preds = %23
  %33 = load i32, ptr %6, align 4, !tbaa !5
  %34 = add nsw i32 %33, 1
  store i32 %34, ptr %6, align 4, !tbaa !5
  br label %17, !llvm.loop !11

35:                                               ; preds = %22
  %36 = load ptr, ptr %5, align 8, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #4
  ret ptr %36
}

; Function Attrs: nounwind
declare double @pow(double noundef, double noundef) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #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) #2

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 = { nounwind "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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 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 = !{!10, !10, i64 0}
!10 = !{!"any pointer", !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: nofree nounwind uwtable
define dso_local noalias noundef ptr @grayCode(i32 noundef %0, ptr nocapture noundef writeonly %1) local_unnamed_addr #0 {
  %ldexp = tail call double @ldexp(double 1.000000e+00, i32 %0) #3
  %3 = fptosi double %ldexp to i32
  store i32 %3, ptr %1, align 4, !tbaa !5
  %4 = sext i32 %3 to i64
  %5 = shl nsw i64 %4, 2
  %6 = tail call noalias ptr @malloc(i64 noundef %5) #4
  %7 = icmp sgt i32 %3, 0
  br i1 %7, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %2
  %wide.trip.count = zext nneg i32 %3 to i64
  %min.iters.check = icmp ult i32 %3, 8
  br i1 %min.iters.check, label %.lr.ph.preheader13, label %vector.ph

.lr.ph.preheader13:                               ; preds = %middle.block, %.lr.ph.preheader
  %indvars.iv.ph = phi i64 [ 0, %.lr.ph.preheader ], [ %n.vec, %middle.block ]
  br label %.lr.ph

vector.ph:                                        ; preds = %.lr.ph.preheader
  %n.vec = and i64 %wide.trip.count, 2147483640
  br label %vector.body

vector.body:                                      ; preds = %vector.body, %vector.ph
  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
  %vec.ind = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, %vector.ph ], [ %vec.ind.next, %vector.body ]
  %step.add = add <4 x i32> %vec.ind, <i32 4, i32 4, i32 4, i32 4>
  %8 = lshr <4 x i32> %vec.ind, <i32 1, i32 1, i32 1, i32 1>
  %9 = lshr <4 x i32> %step.add, <i32 1, i32 1, i32 1, i32 1>
  %10 = xor <4 x i32> %8, %vec.ind
  %11 = xor <4 x i32> %9, %step.add
  %12 = getelementptr inbounds i32, ptr %6, i64 %index
  %13 = getelementptr inbounds i8, ptr %12, i64 16
  store <4 x i32> %10, ptr %12, align 4, !tbaa !5
  store <4 x i32> %11, ptr %13, align 4, !tbaa !5
  %index.next = add nuw i64 %index, 8
  %vec.ind.next = add <4 x i32> %vec.ind, <i32 8, i32 8, i32 8, i32 8>
  %14 = icmp eq i64 %index.next, %n.vec
  br i1 %14, label %middle.block, label %vector.body, !llvm.loop !9

middle.block:                                     ; preds = %vector.body
  %cmp.n = icmp eq i64 %n.vec, %wide.trip.count
  br i1 %cmp.n, label %._crit_edge, label %.lr.ph.preheader13

._crit_edge:                                      ; preds = %.lr.ph, %middle.block, %2
  ret ptr %6

.lr.ph:                                           ; preds = %.lr.ph.preheader13, %.lr.ph
  %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ %indvars.iv.ph, %.lr.ph.preheader13 ]
  %15 = trunc nuw nsw i64 %indvars.iv to i32
  %16 = lshr i32 %15, 1
  %17 = xor i32 %16, %15
  %18 = getelementptr inbounds i32, ptr %6, i64 %indvars.iv
  store i32 %17, ptr %18, 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 %.lr.ph, !llvm.loop !13
}

; Function Attrs: mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(inaccessiblemem: readwrite)
declare noalias noundef ptr @malloc(i64 noundef) local_unnamed_addr #1

; Function Attrs: nofree willreturn
declare double @ldexp(double, i32) local_unnamed_addr #2

attributes #0 = { nofree 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 = { 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 #2 = { nofree willreturn }
attributes #3 = { nounwind }
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 = 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, !12, !11}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,IPSCCPPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LoopLoadEliminationPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,LoopVectorizePass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass