On 2024-09-06 10:04, Emanuele Rocca wrote: > The problem seems to be a GCC 14 regression, given that with GCC 13 and > optimization level -O2 the build is fine.
The issue seems related to the new optimization pass to fuse loads and stores to adjacent memory locations into load and store-pair introduced in GCC 14. In both testloadertags_exec and testbuiltins_exec the segfaults happen in a ldp instruction. See eg. in testloadertags_exec: - gdb ./bin/testloadertags_exec (gdb) disassemble Dump of assembler code for function _ZN8QVariantC2ERKS_: 0x0000fffff7ac5040 <+0>: paciasp 0x0000fffff7ac5044 <+4>: stp x29, x30, [sp, #-32]! 0x0000fffff7ac5048 <+8>: mov x29, sp => 0x0000fffff7ac504c <+12>: ldp q31, q30, [x1] 0x0000fffff7ac5050 <+16>: str q30, [sp, #16] I thus tried to build the package with -O2 -mno-late-ldp-fusion, and indeed it builds fine: https://people.debian.org/~ema/kf6-ktexttemplate-gcc-14-no-early-ldp-fusion.log Specifically, I used the following command: sbuild --chroot-setup-commands='printf "APPEND CXXFLAGS -mno-late-ldp-fusion\n" > /etc/dpkg/buildflags.conf Using -O2 -mno-early-ldp-fusion the tests segfault, so the problem seems to be due to the optimizations performed after register allocation.
