[perl #132750] Uninitialized variable usage

# New Ticket Created by  Sergey Aleynikov 
# Please include the string:  [perl #132750]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=132750 >


This is a bug report for perl from sergey.aleynikov@gmail.com,
generated with the help of perlbug 1.41 running under perl 5.27.7.


-----------------------------------------------------------------
[Please describe your issue here]

Recent commit ba52ce15fe5ca68de1be69e394f41ccb48a731cc (HEAD)
Author: Karl Williamson <khw@cpan.org>
Date:   Tue Dec 19 16:03:39 2017 -0700

    Deprecate above \xFF in bitwise string ops

introduced the following build warning which hints at an uninitialized
variable usage:

doop.c:1105:18: warning: variable 'len' is used uninitialized whenever
'if' condition is false [-Wsometimes-uninitialized]
        else if (right_utf8) {
                 ^~~~~~~~~~
doop.c:1119:15: note: uninitialized use occurs here
    lensave = len;
              ^~~
doop.c:1105:14: note: remove the 'if' if its condition is always true
        else if (right_utf8) {
             ^~~~~~~~~~~~~~~~
doop.c:1021:15: note: initialize the variable 'len' to silence this warning
    STRLEN len;
              ^
               = 0

[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
    category=core
    severity=high
---
Site configuration information for perl 5.27.7:

Configured by dur-randir at Fri Dec  1 17:01:46 MSK 2017.

Summary of my perl5 (revision 5 version 27 subversion 7) configuration:
  Commit id: 3c67ad9b9e6d659feb76f3acfc9f81cfe59e3660
  Platform:
    osname=darwin
    osvers=13.4.0
    archname=darwin-2level
    uname='darwin isengard.local 13.4.0 darwin kernel version 13.4.0:
mon jan 11 18:17:34 pst 2016; root:xnu-2422.115.15~1release_x86_64
x86_64 '
    config_args='-de -Dusedevel -DDEBUGGING'
    hint=recommended
    useposix=true
    d_sigaction=define
    useithreads=undef
    usemultiplicity=undef
    use64bitint=define
    use64bitall=define
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=define
    bincompat5005=undef
  Compiler:
    cc='cc'
    ccflags ='-fno-common -DPERL_DARWIN -mmacosx-version-min=10.9
-DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector
-I/usr/local/include -DPERL_USE_SAFE_PUTENV'
    optimize='-O3 -g'
    cppflags='-fno-common -DPERL_DARWIN -mmacosx-version-min=10.9
-DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector
-I/usr/local/include'
    ccversion=''
    gccversion='4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.56)'
    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='double'
    nvsize=8
    Off_t='off_t'
    lseeksize=8
    alignbytes=8
    prototype=define
  Linker and Libraries:
    ld='cc'
    ldflags =' -mmacosx-version-min=10.9 -fstack-protector -L/usr/local/lib'
    libpth=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/6.0/lib
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/usr/lib
/usr/local/lib /usr/lib
    libs=-lpthread -lgdbm -ldbm -ldl -lm -lutil -lc
    perllibs=-lpthread -ldl -lm -lutil -lc
    libc=
    so=dylib
    useshrplib=false
    libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs
    dlext=bundle
    d_dlsymun=undef
    ccdlflags=' '
    cccdlflags=' '
    lddlflags=' -mmacosx-version-min=10.9 -bundle -undefined
dynamic_lookup -L/usr/local/lib -fstack-protector'


---
@INC for perl 5.27.7:
    lib
    /usr/local/lib/perl5/site_perl/5.27.7/darwin-2level
    /usr/local/lib/perl5/site_perl/5.27.7
    /usr/local/lib/perl5/5.27.7/darwin-2level
    /usr/local/lib/perl5/5.27.7

---
Environment for perl 5.27.7:
    DYLD_LIBRARY_PATH (unset)
    HOME=/Users/dur-randir
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/Users/dur-randir/perlbrew/bin:/Users/dur-randir/perlbrew/perls/perl-5.22.1/bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/texbin
    PERLBREW_BASHRC_VERSION=0.78
    PERLBREW_HOME=/Users/dur-randir/.perlbrew
    PERLBREW_MANPATH=/Users/dur-randir/perlbrew/perls/perl-5.22.1/man
    PERLBREW_PATH=/Users/dur-randir/perlbrew/bin:/Users/dur-randir/perlbrew/perls/perl-5.22.1/bin
    PERLBREW_PERL=perl-5.22.1
    PERLBREW_ROOT=/Users/dur-randir/perlbrew
    PERLBREW_VERSION=0.78
    PERL_BADLANG (unset)
    SHELL=/usr/local/bin/zsh

• [perl #132750] Uninitialized variable usage by Karl Williamson via RT
• [perl #132750] Uninitialized variable usage by Sergey Aleynikov