https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81897
--- Comment #17 from Arnd Bergmann <arnd at linaro dot org> --- Created attachment 43057 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43057&action=edit linux/drivers/scsi/lpfc/lpfc_bsg.c, preprocessed and compressed A possibly related warning I just saw this week, with and without the gcc patch, and back to gcc-4.5+: x86_64-linux-gcc-8.0.0 -fno-strict-aliasing -Wall -O2 -Wno-pointer-sign -m32 -c -xc lpfc_bsg.i /git/arm-soc/drivers/scsi/lpfc/lpfc_bsg.c: In function 'lpfc_bsg_rport_els_cmp': /git/arm-soc/drivers/scsi/lpfc/lpfc_bsg.c:632:22: warning: 'bsg_reply' may be used uninitialized in this function [-Wmaybe-uninitialized] reduced to 8<---- long current_stack_pointer, lpfc_bsg_rport_els_cmp_rsp_0; long pv_irq_ops_1_0, pv_irq_ops_0_0; struct bsg_job { void *reply; }; struct fc_bsg_reply { int reply_payload_rcv_len; struct bsg_job set_job; } * lpfc_bsg_rport_els_cmp_dd_data; static void check(long v) { if (v) { asm(""); __builtin_unreachable(); } } void lpfc_bsg_rport_els_cmp(void) { struct bsg_job *job; struct fc_bsg_reply *bsg_reply; job = &lpfc_bsg_rport_els_cmp_dd_data->set_job; if (job) bsg_reply = job->reply; check(pv_irq_ops_0_0); check(pv_irq_ops_1_0); asm("" : "+r"(current_stack_pointer)); check(pv_irq_ops_0_0); check(pv_irq_ops_1_0); if (job) { if (lpfc_bsg_rport_els_cmp_rsp_0 == 0) bsg_reply->reply_payload_rcv_len = 0; else if (lpfc_bsg_rport_els_cmp_rsp_0 == 1) bsg_reply->reply_payload_rcv_len = 0; } } ---->8 This looked similar to the originally reported symptom in the source code. The reduced version looks quite a bit different, so no idea if this is something else entirely or not.
