From: Jan Hubicka Date: Sat, 7 May 2011 20:31:37 +0000 (+0200) Subject: ipa-inline-transform.c (inline_call): Account when program size decreases. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b4c0a88402b1615070601460dcbccb65fd7d3a18;p=gcc.git ipa-inline-transform.c (inline_call): Account when program size decreases. * ipa-inline-transform.c (inline_call): Account when program size decreases. * ipa-inline.c (relative_time_benefit): New function. (edge_badness): Reorganize to be power 2 based; fix thinko when computing badness for negative growth; update comments to match reality; better dumps. From-SVN: r173537 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 61b6bcd0048..bf01f7bf468 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2011-05-07 Jan Hubicka + + * ipa-inline-transform.c (inline_call): Account when program size decreases. + * ipa-inline.c (relative_time_benefit): New function. + (edge_badness): Reorganize to be power 2 based; fix + thinko when computing badness for negative growth; update + comments to match reality; better dumps. + 2011-05-07 Eric Botcazou * langhooks.h (lang_hooks_for_types): Change global_bindings_p's return diff --git a/gcc/ipa-inline-transform.c b/gcc/ipa-inline-transform.c index 117958ccf03..cf24a62caf7 100644 --- a/gcc/ipa-inline-transform.c +++ b/gcc/ipa-inline-transform.c @@ -184,7 +184,7 @@ inline_call (struct cgraph_edge *e, bool update_original, old_size = inline_summary (to)->size; inline_merge_summary (e); new_size = inline_summary (to)->size; - if (overall_size && new_size > old_size) + if (overall_size) *overall_size += new_size - old_size; ncalls_inlined++; diff --git a/gcc/ipa-inline.c b/gcc/ipa-inline.c index 4f666040be2..fbc6918c12b 100644 --- a/gcc/ipa-inline.c +++ b/gcc/ipa-inline.c @@ -666,6 +666,37 @@ want_inline_function_called_once_p (struct cgraph_node *node) return true; } + +/* Return relative time improvement for inlining EDGE in range + 1...2^9. */ + +static inline int +relative_time_benefit (struct inline_summary *callee_info, + struct cgraph_edge *edge, + int time_growth) +{ + int relbenefit; + gcov_type uninlined_call_time; + + uninlined_call_time = + ((gcov_type) + (callee_info->time + + inline_edge_summary (edge)->call_stmt_time + + CGRAPH_FREQ_BASE / 2) * edge->frequency + / CGRAPH_FREQ_BASE); + /* Compute relative time benefit, i.e. how much the call becomes faster. + ??? perhaps computing how much the caller+calle together become faster + would lead to more realistic results. */ + if (!uninlined_call_time) + uninlined_call_time = 1; + relbenefit = + (uninlined_call_time - time_growth) * 256 / (uninlined_call_time); + relbenefit = MIN (relbenefit, 512); + relbenefit = MAX (relbenefit, 1); + return relbenefit; +} + + /* A cost model driving the inlining heuristics in a way so the edges with smallest badness are inlined first. After each inlining is performed the costs of all caller edges of nodes affected are recomputed so the @@ -690,7 +721,7 @@ edge_badness (struct cgraph_edge *edge, bool dump) fprintf (dump_file, " Badness calculation for %s -> %s\n", cgraph_node_name (edge->caller), cgraph_node_name (edge->callee)); - fprintf (dump_file, " growth size %i, time %i\n", + fprintf (dump_file, " size growth %i, time growth %i\n", growth, time_growth); } @@ -698,26 +729,29 @@ edge_badness (struct cgraph_edge *edge, bool dump) /* Always prefer inlining saving code size. */ if (growth <= 0) { - badness = INT_MIN - growth; + badness = INT_MIN / 2 + growth; if (dump) - fprintf (dump_file, " %i: Growth %i < 0\n", (int) badness, + fprintf (dump_file, " %i: Growth %i <= 0\n", (int) badness, growth); } - /* When profiling is available, base priorities -(#calls / growth). - So we optimize for overall number of "executed" inlined calls. */ + /* When profiling is available, compute badness as: + + relative_edge_count * relative_time_benefit + goodness = ------------------------------------------- + edge_growth + badness = -goodness + + The fraction is upside down, becuase on edge counts and time beneits + the bounds are known. Edge growth is essentially unlimited. */ + else if (max_count) { - int benefitperc; - benefitperc = (((gcov_type)callee_info->time - * edge->frequency / CGRAPH_FREQ_BASE - time_growth) * 100 - / (callee_info->time + 1) + 1); - benefitperc = MIN (benefitperc, 100); - benefitperc = MAX (benefitperc, 0); + int relbenefit = relative_time_benefit (callee_info, edge, time_growth); badness = ((int) - ((double) edge->count * INT_MIN / max_count / 100) * - benefitperc) / growth; + ((double) edge->count * INT_MIN / 2 / max_count / 512) * + relative_time_benefit (callee_info, edge, time_growth)) / growth; /* Be sure that insanity of the profile won't lead to increasing counts in the scalling and thus to overflow in the computation above. */ @@ -729,51 +763,62 @@ edge_badness (struct cgraph_edge *edge, bool dump) " * Relative benefit %f\n", (int) badness, (double) badness / INT_MIN, (double) edge->count / max_count, - (double) benefitperc); + relbenefit * 100 / 256.0); } } - /* When function local profile is available, base priorities on - growth / frequency, so we optimize for overall frequency of inlined - calls. This is not too accurate since while the call might be frequent - within function, the function itself is infrequent. + /* When function local profile is available. Compute badness as: - Other objective to optimize for is number of different calls inlined. - We add the estimated growth after inlining all functions to bias the - priorities slightly in this direction (so fewer times called functions - of the same size gets priority). */ + + growth_of_callee + badness = -------------------------------------- + growth_for-all + relative_time_benefit * edge_frequency + + */ else if (flag_guess_branch_prob) { - int div = edge->frequency * 100 / CGRAPH_FREQ_BASE + 1; - int benefitperc; + int div = edge->frequency * (1<<10) / CGRAPH_FREQ_MAX; int growth_for_all; - badness = growth * 10000; - benefitperc = (((gcov_type)callee_info->time - * edge->frequency / CGRAPH_FREQ_BASE - time_growth) * 100 - / (callee_info->time + 1) + 1); - benefitperc = MIN (benefitperc, 100); - benefitperc = MAX (benefitperc, 0); - div *= benefitperc; - /* Decrease badness if call is nested. */ - /* Compress the range so we don't overflow. */ - if (div > 10000) - div = 10000 + ceil_log2 (div) - 8; - if (div < 1) - div = 1; - if (badness > 0) - badness /= div; + div = MAX (div, 1); + gcc_checking_assert (edge->frequency <= CGRAPH_FREQ_MAX); + div *= relative_time_benefit (callee_info, edge, time_growth); + + /* frequency is normalized in range 1...2^10. + relbenefit in range 1...2^9 + DIV should be in range 1....2^19. */ + gcc_checking_assert (div >= 1 && div <= (1<<19)); + + /* Result must be integer in range 0...INT_MAX. + Set the base of fixed point calculation so we don't lose much of + precision for small bandesses (those are interesting) yet we don't + overflow for growths that are still in interesting range. */ + badness = ((gcov_type)growth) * (1<<18); + badness = (badness + div / 2) / div; + + /* Overall growth of inlining all calls of function matters: we want to + inline so offline copy of function is no longer needed. + + Additionally functions that can be fully inlined without much of + effort are better inline candidates than functions that can be fully + inlined only after noticeable overall unit growths. The latter + are better in a sense compressing of code size by factoring out common + code into separate function shared by multiple code paths. + + We might mix the valud into the fraction by taking into account + relative growth of the unit, but for now just add the number + into resulting fraction. */ growth_for_all = estimate_growth (edge->callee); badness += growth_for_all; - if (badness > INT_MAX) - badness = INT_MAX; + if (badness > INT_MAX - 1) + badness = INT_MAX - 1; if (dump) { fprintf (dump_file, - " %i: guessed profile. frequency %i, overall growth %i," - " benefit %i%%, divisor %i\n", - (int) badness, edge->frequency, growth_for_all, - benefitperc, div); + " %i: guessed profile. frequency %f, overall growth %i," + " benefit %f%%, divisor %i\n", + (int) badness, (double)edge->frequency / CGRAPH_FREQ_BASE, growth_for_all, + relative_time_benefit (callee_info, edge, time_growth) * 100 / 256.0, div); } } /* When function local profile is not available or it does not give @@ -823,7 +868,6 @@ update_edge_key (fibheap_t heap, struct cgraph_edge *edge) a minimum of heap. */ if (badness < n->key) { - fibheap_replace_key (heap, n, badness); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, @@ -833,6 +877,7 @@ update_edge_key (fibheap_t heap, struct cgraph_edge *edge) (int)n->key, badness); } + fibheap_replace_key (heap, n, badness); gcc_checking_assert (n->key == badness); } }