On 7/1/19 2:52 AM, Aldy Hernandez wrote:
> As discussed before, this enforces types on undefined and varying, which
> makes everything more regular, and removes some special casing
> throughout range handling.
>
> The min/max fields will contain TYPE_MIN_VALUE and TYPE_MAX_VALUE, which
> will make it easy to get at the bounds of a range later on. Since
> pointers don't have TYPE_MIN/MAX_VALUE, we are using build_zero_cst()
> and wide_int_to_tree(wi::max_value(precision)), for consistency.
> UNDEFINED is set similarly, though nobody should ever ask for anything
> except type() from it. That is, no one should be asking for the bounds.
>
> There is one wrinkle, ipa-cp creates VR_VARYING ranges of floats,
> presumably to pass around state?? This causes value_range_base::type()
> and others to fail, even though I haven't actually seen a case of
> someone actually trying to set a VR_RANGE of a float. For now, I've
> built a NOP_EXPR wrapper so type() works correctly. The correct
> approach would probably be to avoid creating these varying/undefined
> ranges in ipa-cp, but I don't have enough ipa-cp-foo to do so.
> Suggestions welcome, if you don't like special casing this for ipa-cp.
> Or perhaps as a follow up.
No idea why we create ranges of floats from ipa-cp. I presume it's
coming from propagate_vr_across_jump_function? Or somewhere else?
>
> In this patch I start introducing a couple small API changes that will
> be needed for range-ops. Since they're needed/useful for this patch, I
> started adding them on a need-to-use basis. They are:
>
> value_range_base (tree type)
>
> This is our constructor for building a varying:
> value_range_base foo (some_type);
>
> value_range_base::supports_type_p(tree type)
>
> We use this instead of having to test everywhere for
> INTEGRAL_TYPE_P and POINTER_TYPE_P which VRP uses throughout.
> I have not ported every use of the INTEGRAL || POINTER in the
> compiler to this function. But that could be a follow up
> cleanup if someone (else) is interested :).
Cleanups of this nature are pre-approved once this patch is ACK'd and
installed.
>
> value_range_base_normalize_symbolics():
>
> This normalizes symbolics into constants. In VRP we usually
> normalize necessary symbolics into [MIN, MAX]. This patch does
> slightly better. Now we transform:
>
> // [SYM, SYM] -> VARYING
> // [SYM, NUM] -> [-MIN, NUM]
> // [NUM, SYM] -> [NUM, +MAX]
> // ~[SYM, NUM] -> [NUM + 1, +MAX]
> // ~[NUM, SYM] -> [-MIN, NUM - 1]
>
> TBH, this bit and its use in *multiplicative_op probably fits
> better with the canonicalization patch, but as I said. They're
> a bit intertwined. Ughh.
I think it does fit better there, but we ought to be able to manage.
>
> Finally, as you mentioned before, we need a way of caching varyings in
> the allocation pool. The type_range_cache class in the attached patch
> is Andrew's doing, but I'll be happy to take the blame and address
> anything that needs doing.
>
> Tested on x86-64 Linux with --enable-languages=all.
>
> Aldy
>
> range-ops-type.patch
>
> commit 24c3a6a2cb7424a9c022930cada3a5f3c84a388a
> Author: Aldy Hernandez <al...@redhat.com>
> Date: Fri Jun 28 11:00:10 2019 +0200
>
> VR_UNDEFINED and VR_VARYING now have a type.
>
> diff --git a/gcc/ChangeLog b/gcc/ChangeLog
> index 01fb97cedb2..a5247735694 100644
> --- a/gcc/ChangeLog
> +++ b/gcc/ChangeLog
> @@ -1,3 +1,72 @@
> +2019-07-01 Aldy Hernandez <al...@redhat.com>
> +
> + * gimple-ssa-evrp-analyze.c (record_ranges_from_phis): Skip PHIs
> + who's result are not valid for a value_range.
> + Set type for varying value_range.
> + * ipa-cp.c (ipcp_vr_lattice::init): Set type for varying/undef
> + value_range.
> + (ipcp_vr_lattice::set_to_bottom): Same.
> + (initialize_node_lattices): Same.
> + * tree-ssa-threadedge.c (record_temporary_equivalences_from_phis):
> + Same.
> + * tree-ssanames.c (get_range_info): Same.
> + * tree-vrp.c (value_range::set_equiv): Do not set equiv on
> + undef/varying.
> + (value_range_base::value_range_base): New constructor.
> + (value_range_base::check): Remove assert for empty min/max.
> + (value_range_base::equal_p): Allow comparison of typeless undefs.
> + (value_range_base::set_undefined): Add type.
> + (value_range::set_undefined): Same.
> + (value_range_base::set_varying): Same.
> + (value_range::set_varying): Same.
> + (value_range_base::type): Remove assert.
> + (value_range_base::dump): Display type for varying/undef.
> + (value_range_base::dump): Add argument-less overload.
> + (value_range::dump): Same.
> + (vrp_val_max): Add handle_pointers argument.
> + (vrp_val_min): Same.
> + (vrp_val_is_max): Same.
> + (vrp_val_is_min): Same.
> + (value_range_base::set_and_canonicalize): Adjust so type is
> + allowed for varying/undef.
> + (ranges_from_anti_range): Same.
> + (extract_range_from_muliplicative_op): Same.
> + (extract_range_from_binary_expr): Same.
> + (extract_range_from_unary_expr): Same.
> + (vrp_prop::vrp_initialize): Same.
> + (vrp_prop::visit_stmt): Same.
> + (value_range_base::union_helper): Same.
> + (value_range_base::normalize_symbolics): Same.
> + (determine_value_range_1): Same.
> + * tree-vrp.h (value_range_base): Add value_range_base(tree type)
> + constructor.
> + Add dump (), supports_type_p,
> + value_range_base_normalize_symbolics, set_varying, and
> + set_undefined.
> + (value_range): Add set_varying, set_undefined, and dump().
> + (vrp_val_is_min): Add argument.
> + (vrp_val_is_max): Same.
> + (vrp_val_min): Same.
> + (vrp_val_max): Same.
> + (range_includes_zero_p): Adjust for varying/undef with types.
> + * vr-values.c (class type_range_cache): New.
> + (set_value_range_to_truthvalue): Adjust for varying/undef with
> + types.
> + (get_value_range): Same.
> + (vr_values::set_defs_to_varying): Same.
> + (vr_values::update_value_range): Same.
> + (extract_range_for_var_from_comparison_expr): Same.
> + (extract_range_from_binary_expr): Same.
> + (extract_range_from_cond_expr): Same.
> + (check_for_binary_op_overflow): Same.
> + (extract_range_basic): Same.
> + (extract_range_from_assignment): Same.
> + (vr_values::vr_values): Initialize type cache.
> + (vr_values::~vr_values): Free type cache.
> + (extract_range_from_phi_node): Adjust for varying/undef with
> + types.
> + * vr-values.h (class vr_values): Add type_cache.
> +
> 2019-06-26 Jeff Law <l...@redhat.com>
>
> +
> +/* Allocate a new range from the obstack and set it to VARYING for TYPE. */
> +inline value_range *
> +type_range_cache::new_varying (tree type)
> +{
> + /* Allocate memory. */
> + void *p = XOBNEW (&m_range_obj, value_range);
> + /* Invoke the constructors on the memory using placement new. */
> + value_range *new_p = new (p) value_range ();
> + /* Initialize it to varying. */
> + new_p->set_varying (type);
> + return new_p;
> +}
So is placement new C++98/C++03 or C++11?
If the former then we can use it, if the latter we probably can't since
we haven't stepped forward to C++11.
jeff
