https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94734
--- Comment #12 from rguenther at suse dot de <rguenther at suse dot de> --- On Fri, 24 Apr 2020, jakub at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94734 > > --- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> --- > If we don't want to revert the change completely, could we perhaps do: > --- gcc/tree-ssa-phiopt.c.jj 2020-03-19 10:23:50.542872359 +0100 > +++ gcc/tree-ssa-phiopt.c 2020-04-24 10:54:10.341716841 +0200 > @@ -2237,10 +2237,26 @@ cond_store_replacement (basic_block midd > whose value is not available readily, which we want to avoid. */ > if (!nontrap->contains (lhs)) > { > - /* If LHS is a local variable without address-taken, we could > - always safely move down the store. */ > - tree base = get_base_address (lhs); > - if (!auto_var_p (base) || TREE_ADDRESSABLE (base)) > + /* If LHS is an access to a local variable without address-taken > + or its part and the access is provably within the bounds of the > + local variable, we could always safely move down the store. */ > + HOST_WIDE_INT offset, size, decl_size; > + bool reverse; > + tree base = get_ref_base_and_extent_hwi (lhs, &offset, &size, > + &reverse); > + if (base == NULL_TREE || !auto_var_p (base) || TREE_ADDRESSABLE (base)) > + return false; > + if (!DECL_SIZE (base) > + || !tree_fits_shwi_p (DECL_SIZE (base))) > + return false; > + decl_size = tree_to_shwi (DECL_SIZE (base)); > + if (offset < 0 > + || size < 0 > + || decl_size < 0 > + || offset >= decl_size > + || size > decl_size > + || ((unsigned HOST_WIDE_INT) offset + size > + > (unsigned HOST_WIDE_INT) decl_size)) > return false; > } That should be roughly equivalent to if (!nontrap->contains (lhs) || !tree_could_trap_p (lhs)) which for ARRAY_REFs checks in_array_bounds_p.
