On 06/21/2017 10:26 AM, Jan Hubicka wrote:
>>
>> Ok, so I fixed that in the described way. There's one remaining fallout of:
>> gcc/testsuite/gcc.dg/tree-ssa/ipa-split-5.c
>>
>> Where a fnsplit is properly done, but then it's again inlined:
>>
>> Considering split_me.part.0/5 with 23 size
>> to be inlined into test/2 in unknown:0
>> Estimated badness is -0.000001, frequency 0.33.
>> Inlined split_me.part.0 into test which now has time 50.300000 and size 44,
>> net change of +17.
>>
>> Considering split_me.part.0/5 with 23 size
>> to be inlined into test/2 in unknown:0
>> Estimated badness is -0.000001, frequency 0.33.
>> Inlined split_me.part.0 into test which now has time 70.760000 and size 61,
>> net change of +17.
>>
>> Considering split_me.part.0/5 with 23 size
>> to be inlined into test/2 in unknown:0
>> Estimated badness is -0.000001, frequency 0.33.
>> Inlined split_me.part.0 into test which now has time 91.220000 and size 78,
>> net change of +17.
>>
>> Considering split_me.part.0/5 with 23 size
>> to be inlined into test/2 in unknown:0
>> Estimated badness is -0.000001, frequency 0.33.
>> Inlined split_me.part.0 into test which now has time 111.680000 and size
>> 95, net change of +17.
>> Unit growth for small function inlining: 61->129 (111%)
>>
>> ...
>>
>> Any hint how to block the IPA inlining?
>
> I guess you only want to make cold part of split_me bigger or
> just use --param to reduce growth for auto inlining.
>
> How the patch reduces split_me_part considerably?
> Honza
Well, I probably overlooked test results, test works fine.
I'm going to install the patch.
Martin
>>
>> Sending new version of patch.
>> Martin
>>
>>>
>>> I would just move pass_strip_predict_hints pre-IPA and not worry about
>>> them chaining.
>>>
>>> There is problem that after inlining the prediction may expand its scope
>>> and predict branch that it outside of the original function body,
>>> but I do not see very easy solution for that besides not re-doing
>>> prediction (we could also copy probabilities from the inlined function
>>> when they exists and honnor them in the outer function. I am not sure
>>> that is going to improve prediction quality though - extra context
>>> is probably useful)
>>>
>>> Thanks,
>>> Honza
>>>>
>>>> Thanks,
>>>> Martin
>>>>
>>>>>
>>>>> Where did you found this case?
>>>>> Honza
>>>>>>
>>>>>> /* Create a new deep copy of the statement. */
>>>>>> copy = gimple_copy (stmt);
>>>>>> --
>>>>>> 2.13.0
>>>>>>
>>
>
>> >From 84625a782add6ae2ed29630815b61b34a052770a Mon Sep 17 00:00:00 2001
>> From: marxin <mli...@suse.cz>
>> Date: Tue, 6 Jun 2017 10:55:18 +0200
>> Subject: [PATCH 1/2] Make early return predictor more precise.
>>
>> gcc/ChangeLog:
>>
>> 2017-05-26 Martin Liska <mli...@suse.cz>
>>
>> PR tree-optimization/79489
>> * gimplify.c (maybe_add_early_return_predict_stmt): New
>> function.
>> (gimplify_return_expr): Call the function.
>> * predict.c (tree_estimate_probability_bb): Remove handling
>> of early return.
>> * predict.def: Update comment about early return predictor.
>> * gimple-predict.h (is_gimple_predict): New function.
>> * predict.def: Change default value of early return to 66.
>> * tree-tailcall.c (find_tail_calls): Skip GIMPLE_PREDICT
>> statements.
>> * passes.def: Put pass_strip_predict_hints to the beginning of
>> IPA passes.
>> ---
>> gcc/gimple-low.c | 2 ++
>> gcc/gimple-predict.h | 8 ++++++++
>> gcc/gimplify.c | 16 ++++++++++++++++
>> gcc/passes.def | 1 +
>> gcc/predict.c | 41 -----------------------------------------
>> gcc/predict.def | 15 +++------------
>> gcc/tree-tailcall.c | 2 ++
>> 7 files changed, 32 insertions(+), 53 deletions(-)
>>
>> diff --git a/gcc/gimple-low.c b/gcc/gimple-low.c
>> index 619b9d7bfb1..4ea6c3532f3 100644
>> --- a/gcc/gimple-low.c
>> +++ b/gcc/gimple-low.c
>> @@ -30,6 +30,8 @@ along with GCC; see the file COPYING3. If not see
>> #include "calls.h"
>> #include "gimple-iterator.h"
>> #include "gimple-low.h"
>> +#include "predict.h"
>> +#include "gimple-predict.h"
>>
>> /* The differences between High GIMPLE and Low GIMPLE are the
>> following:
>> diff --git a/gcc/gimple-predict.h b/gcc/gimple-predict.h
>> index ba58e12e9e9..0e6c2e1ea01 100644
>> --- a/gcc/gimple-predict.h
>> +++ b/gcc/gimple-predict.h
>> @@ -80,4 +80,12 @@ gimple_build_predict (enum br_predictor predictor, enum
>> prediction outcome)
>> return p;
>> }
>>
>> +/* Return true if GS is a GIMPLE_PREDICT statement. */
>> +
>> +static inline bool
>> +is_gimple_predict (const gimple *gs)
>> +{
>> + return gimple_code (gs) == GIMPLE_PREDICT;
>> +}
>> +
>> #endif /* GCC_GIMPLE_PREDICT_H */
>> diff --git a/gcc/gimplify.c b/gcc/gimplify.c
>> index 9af95a28704..1c6e1591953 100644
>> --- a/gcc/gimplify.c
>> +++ b/gcc/gimplify.c
>> @@ -1428,6 +1428,20 @@ gimplify_bind_expr (tree *expr_p, gimple_seq *pre_p)
>> return GS_ALL_DONE;
>> }
>>
>> +/* Maybe add early return predict statement to PRE_P sequence. */
>> +
>> +static void
>> +maybe_add_early_return_predict_stmt (gimple_seq *pre_p)
>> +{
>> + /* If we are not in a conditional context, add PREDICT statement. */
>> + if (gimple_conditional_context ())
>> + {
>> + gimple *predict = gimple_build_predict (PRED_TREE_EARLY_RETURN,
>> + NOT_TAKEN);
>> + gimplify_seq_add_stmt (pre_p, predict);
>> + }
>> +}
>> +
>> /* Gimplify a RETURN_EXPR. If the expression to be returned is not a
>> GIMPLE value, it is assigned to a new temporary and the statement is
>> re-written to return the temporary.
>> @@ -1458,6 +1472,7 @@ gimplify_return_expr (tree stmt, gimple_seq *pre_p)
>> || TREE_CODE (ret_expr) == RESULT_DECL
>> || ret_expr == error_mark_node)
>> {
>> + maybe_add_early_return_predict_stmt (pre_p);
>> greturn *ret = gimple_build_return (ret_expr);
>> gimple_set_no_warning (ret, TREE_NO_WARNING (stmt));
>> gimplify_seq_add_stmt (pre_p, ret);
>> @@ -1525,6 +1540,7 @@ gimplify_return_expr (tree stmt, gimple_seq *pre_p)
>>
>> gimplify_and_add (TREE_OPERAND (stmt, 0), pre_p);
>>
>> + maybe_add_early_return_predict_stmt (pre_p);
>> ret = gimple_build_return (result);
>> gimple_set_no_warning (ret, TREE_NO_WARNING (stmt));
>> gimplify_seq_add_stmt (pre_p, ret);
>> diff --git a/gcc/passes.def b/gcc/passes.def
>> index c14f6b9f63c..316e19d12e3 100644
>> --- a/gcc/passes.def
>> +++ b/gcc/passes.def
>> @@ -107,6 +107,7 @@ along with GCC; see the file COPYING3. If not see
>> early optimizations again. It is thus good idea to do this
>> late. */
>> NEXT_PASS (pass_split_functions);
>> + NEXT_PASS (pass_strip_predict_hints);
>> POP_INSERT_PASSES ()
>> NEXT_PASS (pass_release_ssa_names);
>> NEXT_PASS (pass_rebuild_cgraph_edges);
>> diff --git a/gcc/predict.c b/gcc/predict.c
>> index 60d1a094d10..790be9fbf16 100644
>> --- a/gcc/predict.c
>> +++ b/gcc/predict.c
>> @@ -2739,7 +2739,6 @@ tree_estimate_probability_bb (basic_block bb, bool
>> local_only)
>> {
>> edge e;
>> edge_iterator ei;
>> - gimple *last;
>>
>> FOR_EACH_EDGE (e, ei, bb->succs)
>> {
>> @@ -2766,46 +2765,6 @@ tree_estimate_probability_bb (basic_block bb, bool
>> local_only)
>> }
>> }
>>
>> - /* Predict early returns to be probable, as we've already taken
>> - care for error returns and other cases are often used for
>> - fast paths through function.
>> -
>> - Since we've already removed the return statements, we are
>> - looking for CFG like:
>> -
>> - if (conditional)
>> - {
>> - ..
>> - goto return_block
>> - }
>> - some other blocks
>> - return_block:
>> - return_stmt. */
>> - if (e->dest != bb->next_bb
>> - && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
>> - && single_succ_p (e->dest)
>> - && single_succ_edge (e->dest)->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)
>> - && (last = last_stmt (e->dest)) != NULL
>> - && gimple_code (last) == GIMPLE_RETURN)
>> - {
>> - edge e1;
>> - edge_iterator ei1;
>> -
>> - if (single_succ_p (bb))
>> - {
>> - FOR_EACH_EDGE (e1, ei1, bb->preds)
>> - if (!predicted_by_p (e1->src, PRED_NULL_RETURN)
>> - && !predicted_by_p (e1->src, PRED_CONST_RETURN)
>> - && !predicted_by_p (e1->src, PRED_NEGATIVE_RETURN))
>> - predict_edge_def (e1, PRED_TREE_EARLY_RETURN, NOT_TAKEN);
>> - }
>> - else
>> - if (!predicted_by_p (e->src, PRED_NULL_RETURN)
>> - && !predicted_by_p (e->src, PRED_CONST_RETURN)
>> - && !predicted_by_p (e->src, PRED_NEGATIVE_RETURN))
>> - predict_edge_def (e, PRED_TREE_EARLY_RETURN, NOT_TAKEN);
>> - }
>> -
>> /* Look for block we are guarding (ie we dominate it,
>> but it doesn't postdominate us). */
>> if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun) && e->dest != bb
>> diff --git a/gcc/predict.def b/gcc/predict.def
>> index fcda6c48f11..f7b2bf7738c 100644
>> --- a/gcc/predict.def
>> +++ b/gcc/predict.def
>> @@ -128,18 +128,9 @@ DEF_PREDICTOR (PRED_POLYMORPHIC_CALL, "polymorphic
>> call", HITRATE (59), 0)
>> indefinitely. */
>> DEF_PREDICTOR (PRED_RECURSIVE_CALL, "recursive call", HITRATE (75), 0)
>>
>> -/* Branch causing function to terminate is probably not taken.
>> - FIXME: early return currently predicts code:
>> - int foo (int a)
>> - {
>> - if (a)
>> - bar();
>> - else
>> - bar2();
>> - }
>> - even though there is no return statement involved. We probably want to
>> track
>> - this from FE or retire the predictor. */
>> -DEF_PREDICTOR (PRED_TREE_EARLY_RETURN, "early return (on trees)", HITRATE
>> (54), 0)
>> +/* Branch causing function to terminate is probably not taken. */
>> +DEF_PREDICTOR (PRED_TREE_EARLY_RETURN, "early return (on trees)", HITRATE
>> (66),
>> + 0)
>>
>> /* Branch containing goto is probably not taken.
>> FIXME: Currently not used. */
>> diff --git a/gcc/tree-tailcall.c b/gcc/tree-tailcall.c
>> index b7053387e91..6aa9a56462e 100644
>> --- a/gcc/tree-tailcall.c
>> +++ b/gcc/tree-tailcall.c
>> @@ -421,6 +421,7 @@ find_tail_calls (basic_block bb, struct tailcall **ret)
>> if (gimple_code (stmt) == GIMPLE_LABEL
>> || gimple_code (stmt) == GIMPLE_RETURN
>> || gimple_code (stmt) == GIMPLE_NOP
>> + || gimple_code (stmt) == GIMPLE_PREDICT
>> || gimple_clobber_p (stmt)
>> || is_gimple_debug (stmt))
>> continue;
>> @@ -555,6 +556,7 @@ find_tail_calls (basic_block bb, struct tailcall **ret)
>>
>> if (gimple_code (stmt) == GIMPLE_LABEL
>> || gimple_code (stmt) == GIMPLE_NOP
>> + || gimple_code (stmt) == GIMPLE_PREDICT
>> || gimple_clobber_p (stmt)
>> || is_gimple_debug (stmt))
>> continue;
>> --
>> 2.13.1
>>
>
