https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84281
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jason at gcc dot gnu.org,
| |nathan at gcc dot gnu.org
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
The following makes it finish instantanously. I'm a bit worried about the
assert in cxx_eval_store_expression which for ARRAY constructors asserts
if (code == ARRAY_TYPE)
{
HOST_WIDE_INT i
= find_array_ctor_elt (*valp, index, /*insert*/true);
gcc_assert (i >= 0);
cep = CONSTRUCTOR_ELT (*valp, i);
gcc_assert (TREE_CODE (cep->index) != RANGE_EXPR);
not sure if we need to handle RANGE_EXPR here (simply split the thing!).
Jason/Nathan, can any of you pick this up please? This is an opportunity
to save a lot of memory/compile-time for I guess quite common cases
(no need to unshare all the elements nor allocate the index INTEGER_CSTs
which is what gobbles up all the memory in this case...). I'll throw the
patch to testing just in case - but double checking the above assert
by you would be nice (not sure how we could ever end up storing into
sth generated by cxx_eval_vec_init_1, but ...). Not sure how good
testing coverage is in this area either.
Index: gcc/cp/constexpr.c
===================================================================
--- gcc/cp/constexpr.c (revision 257491)
+++ gcc/cp/constexpr.c (working copy)
@@ -2885,7 +2885,6 @@ cxx_eval_vec_init_1 (const constexpr_ctx
unsigned HOST_WIDE_INT max = tree_to_uhwi (array_type_nelts_top (atype));
verify_ctor_sanity (ctx, atype);
vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor);
- vec_alloc (*p, max + 1);
bool pre_init = false;
unsigned HOST_WIDE_INT i;
@@ -2978,13 +2977,14 @@ cxx_eval_vec_init_1 (const constexpr_ctx
{
if (new_ctx.ctor != ctx->ctor)
eltinit = new_ctx.ctor;
- for (i = 1; i < max; ++i)
- {
- idx = build_int_cst (size_type_node, i);
- CONSTRUCTOR_APPEND_ELT (*p, idx, unshare_constructor (eltinit));
- }
+ tree range = build2 (RANGE_EXPR, size_type_node,
+ build_int_cst (size_type_node, 1),
+ build_int_cst (size_type_node, max - 1));
+ CONSTRUCTOR_APPEND_ELT (*p, range, unshare_constructor (eltinit));
break;
}
+ else
+ vec_safe_reserve (*p, max + 1);
}
if (!*non_constant_p)
