06e421c559c63975f29c35ba3588a0e6b0c75eca is the first bad commitcommit 06e421c559c63975f29c35ba3588a0e6b0c75ecaAuthor: Richard Leach <richardleach@users.noreply.github.com>Date:   Fri Dec 9 23:42:32 2022 +0000    S_fold_constants: remove early SvREADONLY(sv) to allow SvIsCOW(sv)    Standard CONST PVs have the IsCOW flag set, meaning that COW can    be used when assigning the CONST to a variable, rather than making    a copy of the buffer. CONST PVs arising from constant folding have    been lacking this flag, leading to unnecessary copying of PV buffers.    This seems to have occurred because a common branch in S_fold_constants    marks SVs as READONLY before the new CONST OP is created. When the OP    is created, the Perl_ck_svconst() check function is called - this is    the same as when a standard CONST OP is created. If the SV is not    already marked as READONLY, the check function will try to set IsCOW    if it is safe to do so, then in either case will make sure that the    READONLY flag is set.    This commit therefore removes the SvREADONLY(sv) statement from    S_fold_constants(), allowing Perl_ck_svconst() to set the IsCOW    and READONLY flags itself. Minor test updates are also included.  ext/Devel-Peek/t/Peek.t | 4 ++-- op.c                    | 4 +++- t/op/undef.t            | 4 +++- 3 files changed, 8 insertions(+), 4 deletions(-)bisect found first bad commit

# perl -V output goes hereSummary of my perl5 (revision 5 version 41 subversion 1) configuration:  Commit id: e9f8aee2bc0fcdce0a13746848aad38c23073ef7  Platform:    osname=linux    osvers=6.5.0-35-generic    archname=x86_64-linux-thread-multi-ld    uname='linux k93jammy 6.5.0-35-generic #35~22.04.1-ubuntu smp preempt_dynamic tue may 7 09:00:52 utc 2 x86_64 x86_64 x86_64 gnulinux '    config_args='-Dprefix=/home/sand/src/perl/repoperls/installed-perls/host/k93jammy/v5.41.1/322f -Dmyhostname=k93jammy -Dinstallusrbinperl=n -Uversiononly -Dusedevel -des -Ui_db -Dlibswanted=cl pthread socket inet nsl gdbm dbm malloc dl ld sun m crypt sec util c cposix posix ucb BSD gdbm_compat -Duseithreads -Duselongdouble -DEBUGGING=-g'    hint=recommended    useposix=true    d_sigaction=define    useithreads=define    usemultiplicity=define    use64bitint=define    use64bitall=define    uselongdouble=define    usemymalloc=n    default_inc_excludes_dot=define  Compiler:    cc='cc'    ccflags ='-D_REENTRANT -D_GNU_SOURCE -fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'    optimize='-O2 -g'    cppflags='-D_REENTRANT -D_GNU_SOURCE -fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'    ccversion=''    gccversion='11.4.0'    gccosandvers=''    intsize=4    longsize=8    ptrsize=8    doublesize=8    byteorder=12345678    doublekind=3    d_longlong=define    longlongsize=8    d_longdbl=define    longdblsize=16    longdblkind=3    ivtype='long'    ivsize=8    nvtype='long double'    nvsize=16    Off_t='off_t'    lseeksize=8    alignbytes=16    prototype=define  Linker and Libraries:    ld='cc'    ldflags =' -fstack-protector-strong -L/usr/local/lib'    libpth=/usr/local/lib /usr/lib/x86_64-linux-gnu /usr/lib /usr/lib64    libs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc    perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc    libc=/lib/x86_64-linux-gnu/libc.so.6    so=so    useshrplib=false    libperl=libperl.a    gnulibc_version='2.35'  Dynamic Linking:    dlsrc=dl_dlopen.xs    dlext=so    d_dlsymun=undef    ccdlflags='-Wl,-E'    cccdlflags='-fPIC'    lddlflags='-shared -O2 -g -L/usr/local/lib -fstack-protector-strong'Characteristics of this binary (from libperl):   Compile-time options:    HAS_LONG_DOUBLE    HAS_STRTOLD    HAS_TIMES    MULTIPLICITY    PERLIO_LAYERS    PERL_COPY_ON_WRITE    PERL_DONT_CREATE_GVSV    PERL_HASH_FUNC_SIPHASH13    PERL_HASH_USE_SBOX32    PERL_MALLOC_WRAP    PERL_OP_PARENT    PERL_PRESERVE_IVUV    PERL_USE_DEVEL    PERL_USE_SAFE_PUTENV    USE_64_BIT_ALL    USE_64_BIT_INT    USE_ITHREADS    USE_LARGE_FILES    USE_LOCALE    USE_LOCALE_COLLATE    USE_LOCALE_CTYPE    USE_LOCALE_NUMERIC    USE_LOCALE_TIME    USE_LONG_DOUBLE    USE_PERLIO    USE_PERL_ATOF    USE_REENTRANT_API    USE_THREAD_SAFE_LOCALE  Built under linux  Compiled at Jul  2 2024 19:27:33  %ENV:    PERL="/tmp/basesmoker-reloperl-Fbf2/bin/perl"    PERL5LIB="/tmp/loop_over_bdir-2248-KZJRDI/Sysync-0.38-0/blib/arch:/tmp/loop_over_bdir-2248-KZJRDI/Sysync-0.38-0/blib/lib"    PERL5OPT=""    PERL5_CPANPLUS_IS_RUNNING="2256"    PERL5_CPAN_IS_RUNNING="2256"    PERL_CANARY_STABILITY_NOPROMPT="1"    PERL_MM_USE_DEFAULT="1"    PERL_USE_UNSAFE_INC="1"  @INC:    /tmp/loop_over_bdir-2248-KZJRDI/Sysync-0.38-0/blib/arch    /tmp/loop_over_bdir-2248-KZJRDI/Sysync-0.38-0/blib/lib    /home/sand/src/perl/repoperls/installed-perls/host/k93jammy/v5.41.1/322f/lib/site_perl/5.41.1/x86_64-linux-thread-multi-ld    /home/sand/src/perl/repoperls/installed-perls/host/k93jammy/v5.41.1/322f/lib/site_perl/5.41.1    /home/sand/src/perl/repoperls/installed-perls/host/k93jammy/v5.41.1/322f/lib/5.41.1/x86_64-linux-thread-multi-ld    /home/sand/src/perl/repoperls/installed-perls/host/k93jammy/v5.41.1/322f/lib/5.41.1    .