Valgrind is not happy

gistfile1.txt

dogbert@dogbert-VirtualBox ~/repos/rakudo $ ./perl6-valgrind-m t/spec/S24-testing/3-output.t
================================================================================================
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.
Valgrind options can be added with MVM_VALGRIND_OPTS environment variable.

This Rakudo version is 2018.06.173.g.9.f.524.d.0 built on MoarVM version 2018.06.203.g.1.b.1.edfe,
running on linuxmint (18.3.Sylvia) / linux (4.10.0.38.generic)
------------------------------------------------------------------------------------------------
==6149== Memcheck, a memory error detector
==6149== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==6149== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==6149== Command: /home/dogbert/repos/rakudo/nqp/MoarVM/../../install/bin/moar --execname=./perl6-valgrind-m --libpath=. --libpath=blib --libpath=/home/dogbert/repos/rakudo/install/share/nqp/lib --libpath=/home/dogbert/repos/rakudo/install/share/nqp/lib /home/dogbert/repos/rakudo/perl6.moarvm --nqp-lib=blib t/spec/S24-testing/3-output.t
==6149== 
==6149== Thread 2:
==6149== Conditional jump or move depends on uninitialised value(s)
==6149==    at 0x50B5E60: lessen_deopt_requires_for_bb (optimize.c:2744)
==6149==    by 0x50B5E60: lessen_deopt_requires (optimize.c:2765)
==6149==    by 0x50B5E60: MVM_spesh_optimize (optimize.c:2787)
==6149==    by 0x50B8667: MVM_spesh_inline_try_get_graph_from_unspecialized (inline.c:233)
==6149==    by 0x50B32C2: optimize_call (optimize.c:1809)
==6149==    by 0x50B4915: optimize_bb_switch (optimize.c:2206)
==6149==    by 0x50B5B57: optimize_bb (optimize.c:2401)
==6149==    by 0x50B5B57: optimize_bb (optimize.c:2413)
==6149==    by 0x50B5B57: optimize_bb (optimize.c:2413)
==6149==    by 0x50B5B57: optimize_bb (optimize.c:2413)
==6149==    by 0x50B5B57: optimize_bb (optimize.c:2413)
==6149==    by 0x50B5B57: optimize_bb (optimize.c:2413)
==6149==    by 0x50B5B57: optimize_bb (optimize.c:2413)
==6149==    by 0x50B5B57: optimize_bb (optimize.c:2413)
==6149==    by 0x50B5D59: optimize_bb (optimize.c:2413)
==6149==    by 0x50B5D59: MVM_spesh_optimize (optimize.c:2776)
==6149==    by 0x50ABD0E: MVM_spesh_candidate_add (candidate.c:62)
==6149==    by 0x50BAFC4: worker (worker.c:16)
==6149==    by 0x502DCC0: thread_initial_invoke (threads.c:59)
==6149==    by 0x500946D: MVM_interp_run (interp.c:92)
==6149==    by 0x502DD45: start_thread (threads.c:87)
==6149==    by 0x5E8B6B9: start_thread (pthread_create.c:333)
==6149== 
==6149== Conditional jump or move depends on uninitialised value(s)
==6149==    at 0x50B5E60: lessen_deopt_requires_for_bb (optimize.c:2744)
==6149==    by 0x50B5E60: lessen_deopt_requires (optimize.c:2765)
==6149==    by 0x50B5E60: MVM_spesh_optimize (optimize.c:2787)
==6149==    by 0x50ABD0E: MVM_spesh_candidate_add (candidate.c:62)
==6149==    by 0x50BAFC4: worker (worker.c:16)
==6149==    by 0x502DCC0: thread_initial_invoke (threads.c:59)
==6149==    by 0x500946D: MVM_interp_run (interp.c:92)
==6149==    by 0x502DD45: start_thread (threads.c:87)
==6149==    by 0x5E8B6B9: start_thread (pthread_create.c:333)