[Bug tree-optimization/94717] [10 Regression] segfault with -O2 -fnon-call-exceptions -ftracer

["jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94717

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Eric Botcazou from comment #3)
> > The compiler is apparently not prepared for new trapping loads.  Fixing...
> 
> No, just a missing check on landing pads:
> 
> index a6687cd9c98..4ab8e0250ab 100644
> --- a/gcc/gimple-ssa-store-merging.c
> +++ b/gcc/gimple-ssa-store-merging.c
> @@ -2680,6 +2680,7 @@ imm_store_chain_info::coalesce_immediate_stores ()
>          p[3] = data;
>          using the bswap framework.  */
>        if (info->bitpos == merged_store->start + merged_store->width
> +         && info->lp_nr == merged_store->lp_nr
>           && merged_store->stores.length () == 1
>           && merged_store->stores[0]->ins_stmt != NULL
>           && info->ins_stmt != NULL)

Shouldn't that be done in try_coalesce_bswap instead?
Because checking lp_nr above will only make sure it is the same between
merged_store and the first store after it, but we are trying to coalesce often
more than that.
By checking it in try_coalesce_bswap, in the first loop in that function, it
will verify all stores.