Remove array_index inliner hint
Jan Hubicka
hubicka@ucw.cz
Sun Jul 14 17:38:00 GMT 2019
Hi,
array_index hint marks functions contains an array reference that
is indexed by value that will become constant after inlining.
This hint is later used by ipa-inline in rather agressive way updating
inline-insns-auto to inline-insns-single for such functions. While tuning
-finline-functions for -O2 I have noticed that this leads to 30% code size
growth of SPEC versions of GCC. This is because all predicates like
register_operand contains such array references based on mode parameter and
this makes GCC to conclude about agressively inlining them all which bloats
insn-* a lot.
This hint was quite early experiment with propagating additional stuff through
inliner. I think it is better to actualy account the instructions which will
be generated for array indexing rather then handling this specially.
This patch makes us to accound 1 instruction for every non-constant array
access. This is still probably making inliner overly optimistic about inlining
benefits since these accesses will later be CSEed, but it kills bit of magic
and makes things more robust.
This will make inliner notice that function will simplify and give it
higher priority for inlining possibly still bypassing the bounds if big
speedup is achieved. This is however a lot more rare than before.
Bootstrapped/regtested x86_64-linux, comitted.
Honza
* ipa-fnsummary.c (ipa_dump_hints): Do not dump array_index.
(ipa_fn_summary::~ipa_fn_summary): Do not destroy array_index.
(ipa_fn_summary_t::duplicate): Do not duplicate array_index.
(array_index_predicate): Remove.
(analyze_function_body): Account cost for variable ofsetted array
indexing.
(estimate_node_size_and_time): Do not compute array index hint.
(ipa_merge_fn_summary_after_inlining): Do not merge array index hint.
(inline_read_section): Do not read array index hint.
(ipa_fn_summary_write): Do not write array index hint.
* doc/invoke.texi (ipa-cp-array-index-hint-bonus): Remove.
* ipa-cp.c (hint_time_bonus): Remove.
* ipa-fnsummary.h (ipa_hints_vals): Remove array_index.
(ipa_fnsummary): Remove array_index.
* ipa-inline.c (want_inline_small_function_p): Do not use
array_index.
(edge_badness): Likewise.
* params.def (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS): Remove.
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi (revision 273450)
+++ doc/invoke.texi (working copy)
@@ -11895,12 +11895,6 @@ of iterations of a loop known, it adds a
@option{ipa-cp-loop-hint-bonus} to the profitability score of
the candidate.
-@item ipa-cp-array-index-hint-bonus
-When IPA-CP determines that a cloning candidate would make the index of
-an array access known, it adds a bonus of
-@option{ipa-cp-array-index-hint-bonus} to the profitability
-score of the candidate.
-
@item ipa-max-aa-steps
During its analysis of function bodies, IPA-CP employs alias analysis
in order to track values pointed to by function parameters. In order
Index: ipa-cp.c
===================================================================
--- ipa-cp.c (revision 273450)
+++ ipa-cp.c (working copy)
@@ -2607,8 +2607,6 @@ hint_time_bonus (ipa_hints hints)
int result = 0;
if (hints & (INLINE_HINT_loop_iterations | INLINE_HINT_loop_stride))
result += PARAM_VALUE (PARAM_IPA_CP_LOOP_HINT_BONUS);
- if (hints & INLINE_HINT_array_index)
- result += PARAM_VALUE (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS);
return result;
}
Index: ipa-fnsummary.c
===================================================================
--- ipa-fnsummary.c (revision 273450)
+++ ipa-fnsummary.c (working copy)
@@ -134,11 +134,6 @@ ipa_dump_hints (FILE *f, ipa_hints hints
hints &= ~INLINE_HINT_declared_inline;
fprintf (f, " declared_inline");
}
- if (hints & INLINE_HINT_array_index)
- {
- hints &= ~INLINE_HINT_array_index;
- fprintf (f, " array_index");
- }
if (hints & INLINE_HINT_known_hot)
{
hints &= ~INLINE_HINT_known_hot;
@@ -549,8 +544,6 @@ ipa_fn_summary::~ipa_fn_summary ()
edge_predicate_pool.remove (loop_iterations);
if (loop_stride)
edge_predicate_pool.remove (loop_stride);
- if (array_index)
- edge_predicate_pool.remove (array_index);
vec_free (conds);
vec_free (size_time_table);
}
@@ -703,8 +696,6 @@ ipa_fn_summary_t::duplicate (cgraph_node
possible_truths);
remap_hint_predicate_after_duplication (&info->loop_stride,
possible_truths);
- remap_hint_predicate_after_duplication (&info->array_index,
- possible_truths);
/* If inliner or someone after inliner will ever start producing
non-trivial clones, we will get trouble with lack of information
@@ -727,12 +718,6 @@ ipa_fn_summary_t::duplicate (cgraph_node
info->loop_stride = NULL;
set_hint_predicate (&info->loop_stride, p);
}
- if (info->array_index)
- {
- predicate p = *info->array_index;
- info->array_index = NULL;
- set_hint_predicate (&info->array_index, p);
- }
}
if (!dst->global.inlined_to)
ipa_update_overall_fn_summary (dst);
@@ -894,11 +879,6 @@ ipa_dump_fn_summary (FILE *f, struct cgr
fprintf (f, " loop stride:");
s->loop_stride->dump (f, s->conds);
}
- if (s->array_index)
- {
- fprintf (f, " array index:");
- s->array_index->dump (f, s->conds);
- }
fprintf (f, " calls:\n");
dump_ipa_call_summary (f, 4, node, s);
fprintf (f, "\n");
@@ -1824,27 +1804,6 @@ predicate_for_phi_result (class ipa_fn_s
nonconstant_names[SSA_NAME_VERSION (gimple_phi_result (phi))] = *p;
}
-/* Return predicate specifying when array index in access OP becomes non-constant. */
-
-static predicate
-array_index_predicate (ipa_fn_summary *info,
- vec< predicate> nonconstant_names, tree op)
-{
- predicate p = false;
- while (handled_component_p (op))
- {
- if (TREE_CODE (op) == ARRAY_REF || TREE_CODE (op) == ARRAY_RANGE_REF)
- {
- if (TREE_CODE (TREE_OPERAND (op, 1)) == SSA_NAME)
- p = p.or_with (info->conds,
- nonconstant_names[SSA_NAME_VERSION
- (TREE_OPERAND (op, 1))]);
- }
- op = TREE_OPERAND (op, 0);
- }
- return p;
-}
-
/* For a typical usage of __builtin_expect (a<b, 1), we
may introduce an extra relation stmt:
With the builtin, we have
@@ -2001,7 +1960,6 @@ analyze_function_body (struct cgraph_nod
vec<predicate> nonconstant_names = vNULL;
int nblocks, n;
int *order;
- predicate array_index = true;
gimple *fix_builtin_expect_stmt;
gcc_assert (my_function && my_function->cfg);
@@ -2146,26 +2104,6 @@ analyze_function_body (struct cgraph_nod
this_time);
}
- if (gimple_assign_load_p (stmt) && nonconstant_names.exists ())
- {
- predicate this_array_index;
- this_array_index =
- array_index_predicate (info, nonconstant_names,
- gimple_assign_rhs1 (stmt));
- if (this_array_index != false)
- array_index &= this_array_index;
- }
- if (gimple_store_p (stmt) && nonconstant_names.exists ())
- {
- predicate this_array_index;
- this_array_index =
- array_index_predicate (info, nonconstant_names,
- gimple_get_lhs (stmt));
- if (this_array_index != false)
- array_index &= this_array_index;
- }
-
-
if (is_gimple_call (stmt)
&& !gimple_call_internal_p (stmt))
{
@@ -2273,14 +2211,40 @@ analyze_function_body (struct cgraph_nod
if (dump_file)
fprintf (dump_file, " fp_expression set\n");
}
+ }
- gcc_assert (time >= 0);
- gcc_assert (size >= 0);
+ /* Account cost of address calculations in the statements. */
+ for (unsigned int i = 0; i < gimple_num_ops (stmt); i++)
+ {
+ for (tree op = gimple_op (stmt, i);
+ op && handled_component_p (op);
+ op = TREE_OPERAND (op, 0))
+ if ((TREE_CODE (op) == ARRAY_REF
+ || TREE_CODE (op) == ARRAY_RANGE_REF)
+ && TREE_CODE (TREE_OPERAND (op, 1)) == SSA_NAME)
+ {
+ predicate p = bb_predicate;
+ if (fbi.info)
+ p = p & will_be_nonconstant_expr_predicate
+ (&fbi, info, TREE_OPERAND (op, 1),
+ nonconstant_names);
+ if (p != false)
+ {
+ time += freq;
+ size += 1;
+ if (dump_file)
+ fprintf (dump_file,
+ "\t\tAccounting address calculation.\n");
+ info->account_size_time (ipa_fn_summary::size_scale,
+ freq,
+ bb_predicate,
+ p);
+ }
+ }
}
+
}
}
- set_hint_predicate (&ipa_fn_summaries->get_create (node)->array_index,
- array_index);
free (order);
if (nonconstant_names.exists () && !early)
@@ -2783,9 +2747,6 @@ estimate_node_size_and_time (struct cgra
if (info->loop_stride
&& !info->loop_stride->evaluate (possible_truths))
hints |= INLINE_HINT_loop_stride;
- if (info->array_index
- && !info->array_index->evaluate (possible_truths))
- hints |= INLINE_HINT_array_index;
if (info->scc_no)
hints |= INLINE_HINT_in_scc;
if (DECL_DECLARED_INLINE_P (node->decl))
@@ -3106,9 +3067,6 @@ ipa_merge_fn_summary_after_inlining (str
remap_hint_predicate (info, callee_info,
&callee_info->loop_stride,
operand_map, offset_map, clause, &toplev_predicate);
- remap_hint_predicate (info, callee_info,
- &callee_info->array_index,
- operand_map, offset_map, clause, &toplev_predicate);
ipa_call_summary *s = ipa_call_summaries->get (edge);
inline_update_callee_summaries (edge->callee, s->loop_depth);
@@ -3366,9 +3324,6 @@ inline_read_section (struct lto_file_dec
p.stream_in (&ib);
if (info)
set_hint_predicate (&info->loop_stride, p);
- p.stream_in (&ib);
- if (info)
- set_hint_predicate (&info->array_index, p);
for (e = node->callees; e; e = e->next_callee)
read_ipa_call_summary (&ib, e, info != NULL);
for (e = node->indirect_calls; e; e = e->next_callee)
@@ -3517,10 +3472,6 @@ ipa_fn_summary_write (void)
info->loop_stride->stream_out (ob);
else
streamer_write_uhwi (ob, 0);
- if (info->array_index)
- info->array_index->stream_out (ob);
- else
- streamer_write_uhwi (ob, 0);
for (edge = cnode->callees; edge; edge = edge->next_callee)
write_ipa_call_summary (ob, edge);
for (edge = cnode->indirect_calls; edge; edge = edge->next_callee)
Index: ipa-fnsummary.h
===================================================================
--- ipa-fnsummary.h (revision 273450)
+++ ipa-fnsummary.h (working copy)
@@ -48,11 +48,8 @@ enum ipa_hints_vals {
if functions are in different modules, inlining may not be so important.
Set by simple_edge_hints in ipa-inline-analysis.c. */
INLINE_HINT_cross_module = 64,
- /* If array indexes of loads/stores become known there may be room for
- further optimization. */
- INLINE_HINT_array_index = 128,
/* We know that the callee is hot by profile. */
- INLINE_HINT_known_hot = 256
+ INLINE_HINT_known_hot = 128
};
typedef int ipa_hints;
@@ -97,7 +94,7 @@ public:
fp_expressions (false), estimated_stack_size (false),
stack_frame_offset (false), time (0), size (0), conds (NULL),
size_time_table (NULL), loop_iterations (NULL), loop_stride (NULL),
- array_index (NULL), growth (0), scc_no (0)
+ growth (0), scc_no (0)
{
}
@@ -111,7 +108,7 @@ public:
stack_frame_offset (s.stack_frame_offset), time (s.time), size (s.size),
conds (s.conds), size_time_table (s.size_time_table),
loop_iterations (s.loop_iterations), loop_stride (s.loop_stride),
- array_index (s.array_index), growth (s.growth), scc_no (s.scc_no)
+ growth (s.growth), scc_no (s.scc_no)
{}
/* Default constructor. */
@@ -157,8 +154,6 @@ public:
/* Predicate on when some loop in the function becomes to have known
stride. */
predicate * GTY((skip)) loop_stride;
- /* Predicate on when some array indexes become constants. */
- predicate * GTY((skip)) array_index;
/* Estimated growth for inlining all copies of the function before start
of small functions inlining.
This value will get out of date as the callers are duplicated, but
Index: ipa-inline.c
===================================================================
--- ipa-inline.c (revision 273450)
+++ ipa-inline.c (working copy)
@@ -807,7 +807,6 @@ want_inline_small_function_p (struct cgr
|| (!(hints & (INLINE_HINT_indirect_call
| INLINE_HINT_known_hot
| INLINE_HINT_loop_iterations
- | INLINE_HINT_array_index
| INLINE_HINT_loop_stride))
&& !(big_speedup = big_speedup_p (e)))))
{
@@ -833,7 +832,6 @@ want_inline_small_function_p (struct cgr
&& !(hints & INLINE_HINT_known_hot)
&& growth >= ((hints & (INLINE_HINT_indirect_call
| INLINE_HINT_loop_iterations
- | INLINE_HINT_array_index
| INLINE_HINT_loop_stride))
? MAX (MAX_INLINE_INSNS_AUTO,
MAX_INLINE_INSNS_SINGLE)
@@ -1227,7 +1225,6 @@ edge_badness (struct cgraph_edge *edge,
badness = badness.shift (badness > 0 ? 4 : -4);
if ((hints & (INLINE_HINT_indirect_call
| INLINE_HINT_loop_iterations
- | INLINE_HINT_array_index
| INLINE_HINT_loop_stride))
|| callee_info->growth <= 0)
badness = badness.shift (badness > 0 ? -2 : 2);
Index: params.def
===================================================================
--- params.def (revision 273450)
+++ params.def (working copy)
@@ -1109,12 +1109,6 @@ DEFPARAM (PARAM_IPA_CP_LOOP_HINT_BONUS,
"bounds or strides known.",
64, 0, 0)
-DEFPARAM (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS,
- "ipa-cp-array-index-hint-bonus",
- "Compile-time bonus IPA-CP assigns to candidates which make an array "
- "index known.",
- 48, 0, 0)
-
DEFPARAM (PARAM_IPA_MAX_AA_STEPS,
"ipa-max-aa-steps",
"Maximum number of statements that will be visited by IPA formal "
More information about the Gcc-patches
mailing list