Segmentation fault

gistfile1.txt

    dogbert@dogbert-VirtualBox:~$ perl6-valgrind-m -e 'my $n := 1; ($n + 1 for ^17000) xx 20'
    ================================================================================================
    This is Rakudo Perl 6 running in valgrind, a tool for debugging and profiling programs.
    Running a program in valgrind usually takes *a lot* more time than running it directly,
    so please be patient.
    This Rakudo version is 2017.07.145.g.76.af.17.a.8.b built on MoarVM version 2017.07.371.gc.663342.b.4,
    running on linuxmint (20.Ulyana) / linux (5.4.0.62.generic)
    ------------------------------------------------------------------------------------------------
    ==627145== Memcheck, a memory error detector
    ==627145== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
    ==627145== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
    ==627145== Command: /home/dogbert/.rakudobrew/versions/moar-76af17a/install/bin/moar --full-cleanup --execname=/home/dogbert/.rakudobrew/versions/moar-76af17a/install/bin/perl6-valgrind-m --libpath=/home/dogbert/.rakudobrew/versions/moar-76af17a/install/share/nqp/lib --libpath=/home/dogbert/.rakudobrew/versions/moar-76af17a/install/share/perl6/lib --libpath=/home/dogbert/.rakudobrew/versions/moar-76af17a/install/share/perl6/runtime /home/dogbert/.rakudobrew/versions/moar-76af17a/install/share/perl6/runtime/perl6.moarvm -e my\ $n\ :=\ 1;\ ($n\ +\ 1\ for\ ^17000)\ xx\ 20
    ==627145== 
    WARNINGS for -e:
    Useless use of "+" in expression "$n + 1" in sink context (line 1)
    ==627145== Thread 2:
    ==627145== Conditional jump or move depends on uninitialised value(s)
    ==627145==    at 0x4A9E76B: find_invokee_static_frame (optimize.c:1272)
    ==627145==    by 0x4A9EB08: optimize_call (optimize.c:1361)
    ==627145==    by 0x4AA0487: optimize_bb (optimize.c:1895)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA1009: MVM_spesh_optimize (optimize.c:2199)
    ==627145==    by 0x4A93DC5: MVM_spesh_candidate_add (candidate.c:62)
    ==627145== 
    ==627145== Conditional jump or move depends on uninitialised value(s)
    ==627145==    at 0x4A9E778: find_invokee_static_frame (optimize.c:1272)
    ==627145==    by 0x4A9EB08: optimize_call (optimize.c:1361)
    ==627145==    by 0x4AA0487: optimize_bb (optimize.c:1895)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA093C: optimize_bb (optimize.c:2064)
    ==627145==    by 0x4AA1009: MVM_spesh_optimize (optimize.c:2199)
    ==627145==    by 0x4A93DC5: MVM_spesh_candidate_add (candidate.c:62)