https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109585
Bug ID: 109585
Summary: Carla/sord miscompiled with -O2 on ARM64 (inlining
issue)
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: hector at marcansoft dot com
Target Milestone: ---
Created attachment 54900
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54900&action=edit
Manually annotated disassembly identifying the problem
GCC 12.1.0 miscompiles sord_free() with -O2 due to bad inlining on ARM64.
Reproducible on Compiler Explorer on 12.2 and also trunk.
https://godbolt.org/z/rvxP1oodh (includes full preprocessed input)
I've attached an annotated disassembly. The problem is that
zix_btree_iter_increment() and zix_btree_iter_is_end() are inlined together
into sord_free(), but the `i->stack[0].node == NULL` check in
zix_btree_iter_is_end() somehow got hoisted before the `f->node = NULL;` in
zix_btree_iter_increment(), so the check fails when it pass (ending the loop),
and then the loop body goes on to deref a NULL pointer.
