https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99447
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Richard Biener from comment #6) > More specifically, likely caused by > g:ae99b315ba5b9e1ccc221b3c45de323cbc574400 which did > > diff --git a/gcc/cfg.c b/gcc/cfg.c > index 529b6ed2105..e8bd1456c9f 100644 > --- a/gcc/cfg.c > +++ b/gcc/cfg.c > @@ -102,8 +102,7 @@ free_block (basic_block bb) > bb->succs = NULL; > vec_free (bb->preds); > bb->preds = NULL; > - /* Do not free BB itself yet since we leak pointers to dead statements > - that points to dead basic blocks. */ > + ggc_free (bb); > } > > /* Free the memory associated with the CFG in FN. */ > > and the backtrace of the crash points at some RTX tree (if gtype-desc from > trunk still matches, it's likely SYMBOL_REF_DECL) refers to a GIMPLE stmt > via the callgraph edge ->call_stmt which refers to the CFG BB it is > contained in. > > unfortunately it's not visible what pass/phase this segfault occurs in > (might be WPA function materialization or ltrans compilation). > > That said, the ggc_free above looks like a bad idea until we can sort out > these issue. So - should we simply revert the change again? Note we can't leave cgraph & edge reclaim to GC when we free a function and at the same time forcefully ggc_free things pointed to (but ultimatively dead). That's in principle true for the gimple stmts themselves as well. It looks like release_function_body simply leaves stmts dangling, it doesn't remove them from blocks (clearing ->bb). We've not seen ICEs from that for unknown reasons. I'm not sure it's worth all the trouble?
