git-bisect-libiberty.sh

#!/bin/bash

#
# Git bisect script to find the source of demangle issues
# 
# $ git bisect start binutils-2_25 binutils-2_24 libiberty
# $ git bisect run ./git-bisect-libiberty.sh
#

ret=0

set -ex

cd libiberty

./configure 

make clean && make

cd testsuite
make test-demangle

cat <<EOF >> demangle-expected
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65732
--format=gnu-v3 --no-params
_ZNK7VectorTIfEmlIfvEES_IDTmlcvf_EcvT__EEERKS2_
VectorT<decltype (((float)())*((float)()))> VectorT<float>::operator*<float, void>(float const&) const
VectorT<float>::operator*<float, void>
EOF

./test-demangle < demangle-expected || ret=1

git checkout demangle-expected

exit $ret

result.txt

492e19d098f4bf4f22bac22815e9cb117be55b33 is the first bad commit
commit 492e19d098f4bf4f22bac22815e9cb117be55b33
Author: ccoutant <ccoutant@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Fri Nov 22 22:25:49 2013 +0000

    Fix demangler to handle conversion operators correctly.
    
    libiberty/
        PR other/59195
        * cp-demangle.c (struct d_info_checkpoint): New struct.
        (struct d_print_info): Add current_template field.
        (d_operator_name): Set flag when processing a conversion
        operator.
        (cplus_demangle_type): When processing <template-args> for
        a conversion operator, backtrack if necessary.
        (d_expression_1): Renamed from d_expression.
        (d_expression): New wrapper around d_expression_1.
        (d_checkpoint): New function.
        (d_backtrack): New function.
        (d_print_init): Initialize current_template.
        (d_print_comp): Set current_template.
        (d_print_cast): Put current_template in scope for
        printing conversion operator name.
        (cplus_demangle_init_info): Initialize is_expression and
        is_conversion.
        * cp-demangle.h (struct d_info): Add is_expression and
        is_conversion fields.
        * testsuite/demangle-expected: New test cases.
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@205292 138bc75d-0d04-0410-961f-82ee72b054a4

:040000 040000 89c323af64e1397e1d3ccc5e815ade220a39724d 232438ed91649e8add143213b5922edb7000e423 M      libiberty
bisect run success

Seems related to https://sourceware.org/bugzilla/show_bug.cgi?id=17066