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bug#21513: (now an infinite loop in grep/tests/triple-backref?)
From: |
Paul Eggert |
Subject: |
bug#21513: (now an infinite loop in grep/tests/triple-backref?) |
Date: |
Sat, 18 Jan 2020 14:16:45 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 |
On 1/18/20 6:44 AM, Martin Liška wrote:
I can confirm that it never finishes on i586.
I can't reproduce the problem, either on Ubuntu 18.04.3 x86-64 (GCC Ubuntu
7.4.0-1ubuntu1~18.04.1) or on Fedora 31 (GCC 9.2.1 20190827 x86-64 (Red Hat
9.2.1-1)). I did what should have been the equivalent of:
git clone https://git.savannah.gnu.org/git/grep.git
# This is commit 23bf27015e0cc45d0012f54b8e24ac19fdca89f7.
cd grep
./bootstrap
./configure --with-included-regex CC='gcc -m32'
make
make check
and it worked for me; the triple-backref test had an XFAIL and did not loop. Can
you send me more-detailed instructions for how to reproduce the bug?
I would recommend to replace DEBUG_ASSERT (num >= 0);
which expands to:
((num >= 0) ? (void) 0 : __builtin_unreachable ());
into:
if (num < 0)
__builtin_abort ();
The regexec.c code doesn't abort, I guess under the theory that one is supposed
to fix the code than insert runtime assertions that slow things down. You can
compile with -DDEBUG if you want it to abort, but be prepared for other grep
tests to fail if you do so. Admittedly this is a messy area.