https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121020
--- Comment #10 from Pengfei Li <Pengfei.Li2 at arm dot com> --- (In reply to Sam James from comment #9) > (In reply to Sam James from comment #8) > > FWIW, I've checked that this reproduces it in a Debian stable container too > (i.e. there's nothing special that the stage1 gcc-trunk/g++-trunk that > CC/CXX should point to must be configured with). Thank you for the information. I've tried with your approach in the past few days. It works, but the behavior is not stable - some GCC trunk commits reproduce it, others don't. After going through all potentially miscompiled functions, I have created a much smaller reproducer that can stably triggers the SegFault. So far, I've done some analysis and found that the problem seems to be related to misaligned access in over-unrolled loops. In fact, the same SegFault can be observed when compiling my reproducer with GCC 15 release (GCC 14 is ok), so the issue seems to have been introduced between 14 and 15. Given this, I don't think my patch is the root cause. It may just expose the issue more frequently. I feel I'm getting very close to identifying the root cause. I expect to give you another update soon in this week.
