Message ID | 3b8ae8ba-97e7-7363-fecc-bd0e0f85abcf@linaro.org |
---|---|
State | New |
Headers | show |
On Fri, Oct 7, 2016 at 2:53 AM, kugan <kugan.vivekanandarajah@linaro.org> wrote: > Hi Richard, > > Thanks for the review. > > > On 09/08/16 18:58, Richard Biener wrote: >> >> On Tue, Aug 9, 2016 at 12:58 AM, kugan >> <kugan.vivekanandarajah@linaro.org> wrote: >>> >>> Hi Jakub, >>> >>> Thanks for the review. >>> >>> On 08/08/16 16:40, Jakub Jelinek wrote: >>>> >>>> >>>> On Mon, Aug 08, 2016 at 01:36:51PM +1000, kugan wrote: >>>>> >>>>> >>>>> diff --git a/gcc/tree-ssanames.h b/gcc/tree-ssanames.h >>>>> index c81b1a1..6e34433 100644 >>>>> --- a/gcc/tree-ssanames.h >>>>> +++ b/gcc/tree-ssanames.h >>>>> @@ -43,6 +43,9 @@ struct GTY(()) ptr_info_def >>>>> above alignment. Access only through the same helper functions >>>>> as >>>>> align >>>>> above. */ >>>>> unsigned int misalign; >>>>> + /* When this pointer is knonw to be nnonnull this would be true >>>>> otherwise >>>>> + false. */ >>>>> + bool nonnull_p; >>>>> }; >>>> >>>> >>>> >>>> Why do you need this? Doesn't the pt.null bit represent that already? >>> >>> >>> >>> It looks like I can use this. As in gcc/tree-ssa-alias.h: >>> >>> /* Nonzero if the points-to set includes 'nothing', the points-to set >>> includes memory at address NULL. */ >>> unsigned int null : 1; >>> >>> But in gcc/tree-ssa-alias.c, ptrs_compare_unequal has the following >>> comment >>> which says: >>> >>> /* ??? We'd like to handle ptr1 != NULL and ptr1 != ptr2 >>> but those require pt.null to be conservatively correct. */ >>> >>> Does that means it can be wrong at times? I haven't looked it in detail >>> yet >>> but if it is, it would be a problem. >> >> >> Yes, this bit is not correctly computed for all cases (well, it works >> for trivial >> ones but for example misses weaks and maybe some other corner-cases). >> >> Currently there are no consumers of this bit so the incorrectness >> doesn't matter. >> >> I suggest you simply use that bit but set it conservatively from PTA (to >> true) >> for now and adjust it from VRP only. >> >> I do have some patches for fixinig some of the .nonnull_p issues in PTA >> but >> they come at a cost of more constraints. > > > Here is a version of the patch that does this. I have a follow up patch to > use this in ipa-vrp. I will send it for review once this is OK. > > Bootstrapped and regression tested on x86_64-linux-gnu with no new > regressions. Is this OK for trunk? @@ -6359,7 +6361,7 @@ find_what_var_points_to (tree fndecl, varinfo_t orig_vi) if (vi->is_artificial_var) { if (vi->id == nothing_id) - pt->null = 1; + ; please leave this here. pt_solution_singleton_p (struct pt_solution *pt, unsigned *uid) { if (pt->anything || pt->nonlocal || pt->escaped || pt->ipa_escaped - || pt->null || pt->vars == NULL + || pt->vars == NULL || !bitmap_single_bit_set_p (pt->vars)) return false; humm... this is a correctness problem I guess. A latent one currently depending on who relies on it. There is a single use of the above predicate which looks for the points-to solution of a __builtin_alloca call. We should somehow arrange for its solution to not include ->null. Or, simpler, change the predicates name to pt_solution_singleton_or_null_p () as the use does not care for pt->null. +void +set_ptr_nonnull (tree name) +{ + gcc_assert (POINTER_TYPE_P (TREE_TYPE (name))); + struct ptr_info_def *pi = get_ptr_info (name); + pi->pt.null = 0; = false; +} There is the question on how pt.null semantics should be with respect to pt.anything, pt.escaped and pt.nonlocal. I think get_ptr_nonnull needs to return false if any of those are set. Richard. > > Thanks, > Kugan > > gcc/ChangeLog: > > 2016-10-07 Kugan Vivekanandarajah <kuganv@linaro.org> > > * tree-ssa-alias.c (dump_points_to_solution): Dump non null as it > is set to null conservatively. > * tree-ssa-structalias.c (find_what_var_points_to): Set to null > conservatively. > (pt_solution_singleton_p): Dont check null. > * tree-ssanames.c (set_ptr_nonnull): New. > (get_ptr_nonnull): Likewise. > * tree-vrp.c (vrp_finalize): Set ptr that are nonnull. > (evrp_dom_walker::before_dom_children): Likewise. > >> >> Richard. >> >>>> Also, formatting and spelling: >>>> s/knonw/known/ >>>> s/nnon/non/ >>>> s/bool /bool / >>> >>> >>> >>> I will change this. >>> >>> Thanks, >>> Kugan >>>> >>>> >>>> >>>> Jakub >>>> >>> >
From 20ef028b2e38e3d91874ba873be10e5dfdac4d05 Mon Sep 17 00:00:00 2001 From: Kugan Vivekanandarajah <kugan.vivekanandarajah@linaro.org> Date: Fri, 30 Sep 2016 09:00:08 +1000 Subject: [PATCH 3/5] Add nonnull to pointer from VRP --- gcc/tree-ssa-alias.c | 4 ++-- gcc/tree-ssa-structalias.c | 6 ++++-- gcc/tree-ssanames.c | 21 +++++++++++++++++++++ gcc/tree-ssanames.h | 2 ++ gcc/tree-vrp.c | 44 +++++++++++++++++++++++++++++--------------- 5 files changed, 58 insertions(+), 19 deletions(-) diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c index 30de461..ccad68d 100644 --- a/gcc/tree-ssa-alias.c +++ b/gcc/tree-ssa-alias.c @@ -515,8 +515,8 @@ dump_points_to_solution (FILE *file, struct pt_solution *pt) if (pt->ipa_escaped) fprintf (file, ", points-to unit escaped"); - if (pt->null) - fprintf (file, ", points-to NULL"); + if (!pt->null) + fprintf (file, ", points-to non NULL"); if (pt->vars) { diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c index be892fd..99b373f8 100644 --- a/gcc/tree-ssa-structalias.c +++ b/gcc/tree-ssa-structalias.c @@ -6349,6 +6349,8 @@ find_what_var_points_to (tree fndecl, varinfo_t orig_vi) *slot = pt = XOBNEW (&final_solutions_obstack, struct pt_solution); memset (pt, 0, sizeof (struct pt_solution)); + /* Conservatively set to NULL from PTA (to true). */ + pt->null = 1; /* Translate artificial variables into SSA_NAME_PTR_INFO attributes. */ @@ -6359,7 +6361,7 @@ find_what_var_points_to (tree fndecl, varinfo_t orig_vi) if (vi->is_artificial_var) { if (vi->id == nothing_id) - pt->null = 1; + ; else if (vi->id == escaped_id) { if (in_ipa_mode) @@ -6569,7 +6571,7 @@ bool pt_solution_singleton_p (struct pt_solution *pt, unsigned *uid) { if (pt->anything || pt->nonlocal || pt->escaped || pt->ipa_escaped - || pt->null || pt->vars == NULL + || pt->vars == NULL || !bitmap_single_bit_set_p (pt->vars)) return false; diff --git a/gcc/tree-ssanames.c b/gcc/tree-ssanames.c index 91a8f97..6b6619f 100644 --- a/gcc/tree-ssanames.c +++ b/gcc/tree-ssanames.c @@ -374,6 +374,27 @@ get_range_info (const_tree name, wide_int *min, wide_int *max) return SSA_NAME_RANGE_TYPE (name); } +/* Set nonnull attribute to pointer NAME. */ + +void +set_ptr_nonnull (tree name) +{ + gcc_assert (POINTER_TYPE_P (TREE_TYPE (name))); + struct ptr_info_def *pi = get_ptr_info (name); + pi->pt.null = 0; +} + +/* Return nonnull attribute of pointer NAME. */ +bool +get_ptr_nonnull (const_tree name) +{ + gcc_assert (POINTER_TYPE_P (TREE_TYPE (name))); + struct ptr_info_def *pi = SSA_NAME_PTR_INFO (name); + if (pi == NULL) + return false; + return !pi->pt.null; +} + /* Change non-zero bits bitmask of NAME. */ void diff --git a/gcc/tree-ssanames.h b/gcc/tree-ssanames.h index 4496e1d..d39cc9d 100644 --- a/gcc/tree-ssanames.h +++ b/gcc/tree-ssanames.h @@ -88,6 +88,8 @@ extern void set_ptr_info_alignment (struct ptr_info_def *, unsigned int, extern void adjust_ptr_info_misalignment (struct ptr_info_def *, unsigned int); extern struct ptr_info_def *get_ptr_info (tree); +extern void set_ptr_nonnull (tree); +extern bool get_ptr_nonnull (const_tree); extern tree copy_ssa_name_fn (struct function *, tree, gimple *); extern void duplicate_ssa_name_ptr_info (tree, struct ptr_info_def *); diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index 0892709..80b7302 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -10593,18 +10593,24 @@ vrp_finalize (bool warn_array_bounds_p) { tree name = ssa_name (i); - if (!name - || POINTER_TYPE_P (TREE_TYPE (name)) - || (vr_value[i]->type == VR_VARYING) - || (vr_value[i]->type == VR_UNDEFINED)) - continue; + if (!name + || (vr_value[i]->type == VR_VARYING) + || (vr_value[i]->type == VR_UNDEFINED) + || (TREE_CODE (vr_value[i]->min) != INTEGER_CST) + || (TREE_CODE (vr_value[i]->max) != INTEGER_CST)) + continue; - if ((TREE_CODE (vr_value[i]->min) == INTEGER_CST) - && (TREE_CODE (vr_value[i]->max) == INTEGER_CST) - && (vr_value[i]->type == VR_RANGE - || vr_value[i]->type == VR_ANTI_RANGE)) - set_range_info (name, vr_value[i]->type, vr_value[i]->min, - vr_value[i]->max); + if (POINTER_TYPE_P (TREE_TYPE (name)) + && ((vr_value[i]->type == VR_RANGE + && range_includes_zero_p (vr_value[i]->min, + vr_value[i]->max) == 0) + || (vr_value[i]->type == VR_ANTI_RANGE + && range_includes_zero_p (vr_value[i]->min, + vr_value[i]->max) == 1))) + set_ptr_nonnull (name); + else if (!POINTER_TYPE_P (TREE_TYPE (name))) + set_range_info (name, vr_value[i]->type, vr_value[i]->min, + vr_value[i]->max); } substitute_and_fold (op_with_constant_singleton_value_range, @@ -10808,17 +10814,25 @@ evrp_dom_walker::before_dom_children (basic_block bb) def_operand_p def_p = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_DEF); /* Set the SSA with the value range. */ if (def_p - && TREE_CODE (DEF_FROM_PTR (def_p)) == SSA_NAME - && INTEGRAL_TYPE_P (TREE_TYPE (DEF_FROM_PTR (def_p)))) + && TREE_CODE (DEF_FROM_PTR (def_p)) == SSA_NAME) { tree def = DEF_FROM_PTR (def_p); value_range *vr = get_value_range (def); - if ((vr->type == VR_RANGE - || vr->type == VR_ANTI_RANGE) + if (INTEGRAL_TYPE_P (TREE_TYPE (DEF_FROM_PTR (def_p))) + && (vr->type == VR_RANGE + || vr->type == VR_ANTI_RANGE) && (TREE_CODE (vr->min) == INTEGER_CST) && (TREE_CODE (vr->max) == INTEGER_CST)) set_range_info (def, vr->type, vr->min, vr->max); + else if (POINTER_TYPE_P (TREE_TYPE (DEF_FROM_PTR (def_p))) + && ((vr->type == VR_RANGE + && range_includes_zero_p (vr->min, + vr->max) == 0) + || (vr->type == VR_ANTI_RANGE + && range_includes_zero_p (vr->min, + vr->max) == 1))) + set_ptr_nonnull (def); } } else -- 2.7.4