https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107498
Bug ID: 107498
Summary: Wrong optimization leads to unaligned access when
compiling OpenLDAP
Product: gcc
Version: 12.2.0
URL: https://bugs.openldap.org/show_bug.cgi?id=9916
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: glaubitz at physik dot fu-berlin.de
CC: ebotcazou at gcc dot gnu.org, jrtc27 at jrtc27 dot com,
matorola at gmail dot com, slyfox at gcc dot gnu.org
Target Milestone: ---
Target: sparc64-*-*
Building OpenLDAP on sparc64-linux-gnu using gcc-12 results in a slapd binary
that crashes with unaligned access ("Bus error").
After investigation, it turned out that this is not a bug in the OpenLDAP code
but gcc-12 which tries to optimize a access to two 2-byte fields in a struct
using a 4-byte store instruction. This fails because the 2-byte fields have
only 2-byte alignment.
More details on the issue can be obtained from the corresponding OpenLDAP bug
report, in particular comment #10 [1].
> [1] https://bugs.openldap.org/show_bug.cgi?id=9916#c10
