| /* Inlining decision heuristics. |
| Copyright (C) 2003, 2004, 2007, 2008, 2009, 2010, 2011 |
| Free Software Foundation, Inc. |
| Contributed by Jan Hubicka |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* Inlining decision heuristics |
| |
| The implementation of inliner is organized as follows: |
| |
| inlining heuristics limits |
| |
| can_inline_edge_p allow to check that particular inlining is allowed |
| by the limits specified by user (allowed function growth, growth and so |
| on). |
| |
| Functions are inlined when it is obvious the result is profitable (such |
| as functions called once or when inlining reduce code size). |
| In addition to that we perform inlining of small functions and recursive |
| inlining. |
| |
| inlining heuristics |
| |
| The inliner itself is split into two passes: |
| |
| pass_early_inlining |
| |
| Simple local inlining pass inlining callees into current function. |
| This pass makes no use of whole unit analysis and thus it can do only |
| very simple decisions based on local properties. |
| |
| The strength of the pass is that it is run in topological order |
| (reverse postorder) on the callgraph. Functions are converted into SSA |
| form just before this pass and optimized subsequently. As a result, the |
| callees of the function seen by the early inliner was already optimized |
| and results of early inlining adds a lot of optimization opportunities |
| for the local optimization. |
| |
| The pass handle the obvious inlining decisions within the compilation |
| unit - inlining auto inline functions, inlining for size and |
| flattening. |
| |
| main strength of the pass is the ability to eliminate abstraction |
| penalty in C++ code (via combination of inlining and early |
| optimization) and thus improve quality of analysis done by real IPA |
| optimizers. |
| |
| Because of lack of whole unit knowledge, the pass can not really make |
| good code size/performance tradeoffs. It however does very simple |
| speculative inlining allowing code size to grow by |
| EARLY_INLINING_INSNS when callee is leaf function. In this case the |
| optimizations performed later are very likely to eliminate the cost. |
| |
| pass_ipa_inline |
| |
| This is the real inliner able to handle inlining with whole program |
| knowledge. It performs following steps: |
| |
| 1) inlining of small functions. This is implemented by greedy |
| algorithm ordering all inlinable cgraph edges by their badness and |
| inlining them in this order as long as inline limits allows doing so. |
| |
| This heuristics is not very good on inlining recursive calls. Recursive |
| calls can be inlined with results similar to loop unrolling. To do so, |
| special purpose recursive inliner is executed on function when |
| recursive edge is met as viable candidate. |
| |
| 2) Unreachable functions are removed from callgraph. Inlining leads |
| to devirtualization and other modification of callgraph so functions |
| may become unreachable during the process. Also functions declared as |
| extern inline or virtual functions are removed, since after inlining |
| we no longer need the offline bodies. |
| |
| 3) Functions called once and not exported from the unit are inlined. |
| This should almost always lead to reduction of code size by eliminating |
| the need for offline copy of the function. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "tm.h" |
| #include "tree.h" |
| #include "tree-inline.h" |
| #include "langhooks.h" |
| #include "flags.h" |
| #include "cgraph.h" |
| #include "diagnostic.h" |
| #include "gimple-pretty-print.h" |
| #include "params.h" |
| #include "fibheap.h" |
| #include "intl.h" |
| #include "tree-pass.h" |
| #include "coverage.h" |
| #include "ggc.h" |
| #include "rtl.h" |
| #include "tree-flow.h" |
| #include "ipa-prop.h" |
| #include "except.h" |
| #include "target.h" |
| #include "ipa-inline.h" |
| #include "ipa-utils.h" |
| |
| /* Statistics we collect about inlining algorithm. */ |
| static int overall_size; |
| static gcov_type max_count; |
| |
| /* Return false when inlining edge E would lead to violating |
| limits on function unit growth or stack usage growth. |
| |
| The relative function body growth limit is present generally |
| to avoid problems with non-linear behavior of the compiler. |
| To allow inlining huge functions into tiny wrapper, the limit |
| is always based on the bigger of the two functions considered. |
| |
| For stack growth limits we always base the growth in stack usage |
| of the callers. We want to prevent applications from segfaulting |
| on stack overflow when functions with huge stack frames gets |
| inlined. */ |
| |
| static bool |
| caller_growth_limits (struct cgraph_edge *e) |
| { |
| struct cgraph_node *to = e->caller; |
| struct cgraph_node *what = cgraph_function_or_thunk_node (e->callee, NULL); |
| int newsize; |
| int limit = 0; |
| HOST_WIDE_INT stack_size_limit = 0, inlined_stack; |
| struct inline_summary *info, *what_info, *outer_info = inline_summary (to); |
| |
| /* Look for function e->caller is inlined to. While doing |
| so work out the largest function body on the way. As |
| described above, we want to base our function growth |
| limits based on that. Not on the self size of the |
| outer function, not on the self size of inline code |
| we immediately inline to. This is the most relaxed |
| interpretation of the rule "do not grow large functions |
| too much in order to prevent compiler from exploding". */ |
| while (true) |
| { |
| info = inline_summary (to); |
| if (limit < info->self_size) |
| limit = info->self_size; |
| if (stack_size_limit < info->estimated_self_stack_size) |
| stack_size_limit = info->estimated_self_stack_size; |
| if (to->global.inlined_to) |
| to = to->callers->caller; |
| else |
| break; |
| } |
| |
| what_info = inline_summary (what); |
| |
| if (limit < what_info->self_size) |
| limit = what_info->self_size; |
| |
| limit += limit * PARAM_VALUE (PARAM_LARGE_FUNCTION_GROWTH) / 100; |
| |
| /* Check the size after inlining against the function limits. But allow |
| the function to shrink if it went over the limits by forced inlining. */ |
| newsize = estimate_size_after_inlining (to, e); |
| if (newsize >= info->size |
| && newsize > PARAM_VALUE (PARAM_LARGE_FUNCTION_INSNS) |
| && newsize > limit) |
| { |
| e->inline_failed = CIF_LARGE_FUNCTION_GROWTH_LIMIT; |
| return false; |
| } |
| |
| if (!what_info->estimated_stack_size) |
| return true; |
| |
| /* FIXME: Stack size limit often prevents inlining in Fortran programs |
| due to large i/o datastructures used by the Fortran front-end. |
| We ought to ignore this limit when we know that the edge is executed |
| on every invocation of the caller (i.e. its call statement dominates |
| exit block). We do not track this information, yet. */ |
| stack_size_limit += ((gcov_type)stack_size_limit |
| * PARAM_VALUE (PARAM_STACK_FRAME_GROWTH) / 100); |
| |
| inlined_stack = (outer_info->stack_frame_offset |
| + outer_info->estimated_self_stack_size |
| + what_info->estimated_stack_size); |
| /* Check new stack consumption with stack consumption at the place |
| stack is used. */ |
| if (inlined_stack > stack_size_limit |
| /* If function already has large stack usage from sibling |
| inline call, we can inline, too. |
| This bit overoptimistically assume that we are good at stack |
| packing. */ |
| && inlined_stack > info->estimated_stack_size |
| && inlined_stack > PARAM_VALUE (PARAM_LARGE_STACK_FRAME)) |
| { |
| e->inline_failed = CIF_LARGE_STACK_FRAME_GROWTH_LIMIT; |
| return false; |
| } |
| return true; |
| } |
| |
| /* Dump info about why inlining has failed. */ |
| |
| static void |
| report_inline_failed_reason (struct cgraph_edge *e) |
| { |
| if (dump_file) |
| { |
| fprintf (dump_file, " not inlinable: %s/%i -> %s/%i, %s\n", |
| xstrdup (cgraph_node_name (e->caller)), e->caller->uid, |
| xstrdup (cgraph_node_name (e->callee)), e->callee->uid, |
| cgraph_inline_failed_string (e->inline_failed)); |
| } |
| } |
| |
| /* Decide if we can inline the edge and possibly update |
| inline_failed reason. |
| We check whether inlining is possible at all and whether |
| caller growth limits allow doing so. |
| |
| if REPORT is true, output reason to the dump file. */ |
| |
| static bool |
| can_inline_edge_p (struct cgraph_edge *e, bool report) |
| { |
| bool inlinable = true; |
| enum availability avail; |
| struct cgraph_node *callee |
| = cgraph_function_or_thunk_node (e->callee, &avail); |
| tree caller_tree = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (e->caller->symbol.decl); |
| tree callee_tree |
| = callee ? DECL_FUNCTION_SPECIFIC_OPTIMIZATION (callee->symbol.decl) : NULL; |
| struct function *caller_cfun = DECL_STRUCT_FUNCTION (e->caller->symbol.decl); |
| struct function *callee_cfun |
| = callee ? DECL_STRUCT_FUNCTION (callee->symbol.decl) : NULL; |
| |
| if (!caller_cfun && e->caller->clone_of) |
| caller_cfun = DECL_STRUCT_FUNCTION (e->caller->clone_of->symbol.decl); |
| |
| if (!callee_cfun && callee && callee->clone_of) |
| callee_cfun = DECL_STRUCT_FUNCTION (callee->clone_of->symbol.decl); |
| |
| gcc_assert (e->inline_failed); |
| |
| if (!callee || !callee->analyzed) |
| { |
| e->inline_failed = CIF_BODY_NOT_AVAILABLE; |
| inlinable = false; |
| } |
| else if (!inline_summary (callee)->inlinable) |
| { |
| e->inline_failed = CIF_FUNCTION_NOT_INLINABLE; |
| inlinable = false; |
| } |
| else if (avail <= AVAIL_OVERWRITABLE) |
| { |
| e->inline_failed = CIF_OVERWRITABLE; |
| return false; |
| } |
| else if (e->call_stmt_cannot_inline_p) |
| { |
| e->inline_failed = CIF_MISMATCHED_ARGUMENTS; |
| inlinable = false; |
| } |
| /* Don't inline if the functions have different EH personalities. */ |
| else if (DECL_FUNCTION_PERSONALITY (e->caller->symbol.decl) |
| && DECL_FUNCTION_PERSONALITY (callee->symbol.decl) |
| && (DECL_FUNCTION_PERSONALITY (e->caller->symbol.decl) |
| != DECL_FUNCTION_PERSONALITY (callee->symbol.decl))) |
| { |
| e->inline_failed = CIF_EH_PERSONALITY; |
| inlinable = false; |
| } |
| /* TM pure functions should not be inlined into non-TM_pure |
| functions. */ |
| else if (is_tm_pure (callee->symbol.decl) |
| && !is_tm_pure (e->caller->symbol.decl)) |
| { |
| e->inline_failed = CIF_UNSPECIFIED; |
| inlinable = false; |
| } |
| /* Don't inline if the callee can throw non-call exceptions but the |
| caller cannot. |
| FIXME: this is obviously wrong for LTO where STRUCT_FUNCTION is missing. |
| Move the flag into cgraph node or mirror it in the inline summary. */ |
| else if (callee_cfun && callee_cfun->can_throw_non_call_exceptions |
| && !(caller_cfun && caller_cfun->can_throw_non_call_exceptions)) |
| { |
| e->inline_failed = CIF_NON_CALL_EXCEPTIONS; |
| inlinable = false; |
| } |
| /* Check compatibility of target optimization options. */ |
| else if (!targetm.target_option.can_inline_p (e->caller->symbol.decl, |
| callee->symbol.decl)) |
| { |
| e->inline_failed = CIF_TARGET_OPTION_MISMATCH; |
| inlinable = false; |
| } |
| /* Check if caller growth allows the inlining. */ |
| else if (!DECL_DISREGARD_INLINE_LIMITS (callee->symbol.decl) |
| && !lookup_attribute ("flatten", |
| DECL_ATTRIBUTES |
| (e->caller->global.inlined_to |
| ? e->caller->global.inlined_to->symbol.decl |
| : e->caller->symbol.decl)) |
| && !caller_growth_limits (e)) |
| inlinable = false; |
| /* Don't inline a function with a higher optimization level than the |
| caller. FIXME: this is really just tip of iceberg of handling |
| optimization attribute. */ |
| else if (caller_tree != callee_tree) |
| { |
| struct cl_optimization *caller_opt |
| = TREE_OPTIMIZATION ((caller_tree) |
| ? caller_tree |
| : optimization_default_node); |
| |
| struct cl_optimization *callee_opt |
| = TREE_OPTIMIZATION ((callee_tree) |
| ? callee_tree |
| : optimization_default_node); |
| |
| if (((caller_opt->x_optimize > callee_opt->x_optimize) |
| || (caller_opt->x_optimize_size != callee_opt->x_optimize_size)) |
| /* gcc.dg/pr43564.c. Look at forced inline even in -O0. */ |
| && !DECL_DISREGARD_INLINE_LIMITS (e->callee->symbol.decl)) |
| { |
| e->inline_failed = CIF_OPTIMIZATION_MISMATCH; |
| inlinable = false; |
| } |
| } |
| |
| if (!inlinable && report) |
| report_inline_failed_reason (e); |
| return inlinable; |
| } |
| |
| |
| /* Return true if the edge E is inlinable during early inlining. */ |
| |
| static bool |
| can_early_inline_edge_p (struct cgraph_edge *e) |
| { |
| struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, |
| NULL); |
| /* Early inliner might get called at WPA stage when IPA pass adds new |
| function. In this case we can not really do any of early inlining |
| because function bodies are missing. */ |
| if (!gimple_has_body_p (callee->symbol.decl)) |
| { |
| e->inline_failed = CIF_BODY_NOT_AVAILABLE; |
| return false; |
| } |
| /* In early inliner some of callees may not be in SSA form yet |
| (i.e. the callgraph is cyclic and we did not process |
| the callee by early inliner, yet). We don't have CIF code for this |
| case; later we will re-do the decision in the real inliner. */ |
| if (!gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->caller->symbol.decl)) |
| || !gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->symbol.decl))) |
| { |
| if (dump_file) |
| fprintf (dump_file, " edge not inlinable: not in SSA form\n"); |
| return false; |
| } |
| if (!can_inline_edge_p (e, true)) |
| return false; |
| return true; |
| } |
| |
| |
| /* Return true when N is leaf function. Accept cheap builtins |
| in leaf functions. */ |
| |
| static bool |
| leaf_node_p (struct cgraph_node *n) |
| { |
| struct cgraph_edge *e; |
| for (e = n->callees; e; e = e->next_callee) |
| if (!is_inexpensive_builtin (e->callee->symbol.decl)) |
| return false; |
| return true; |
| } |
| |
| |
| /* Return true if we are interested in inlining small function. */ |
| |
| static bool |
| want_early_inline_function_p (struct cgraph_edge *e) |
| { |
| bool want_inline = true; |
| struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL); |
| |
| if (DECL_DISREGARD_INLINE_LIMITS (callee->symbol.decl)) |
| ; |
| else if (!DECL_DECLARED_INLINE_P (callee->symbol.decl) |
| && !flag_inline_small_functions) |
| { |
| e->inline_failed = CIF_FUNCTION_NOT_INLINE_CANDIDATE; |
| report_inline_failed_reason (e); |
| want_inline = false; |
| } |
| else |
| { |
| int growth = estimate_edge_growth (e); |
| if (growth <= 0) |
| ; |
| else if (!cgraph_maybe_hot_edge_p (e) |
| && growth > 0) |
| { |
| if (dump_file) |
| fprintf (dump_file, " will not early inline: %s/%i->%s/%i, " |
| "call is cold and code would grow by %i\n", |
| xstrdup (cgraph_node_name (e->caller)), e->caller->uid, |
| xstrdup (cgraph_node_name (callee)), callee->uid, |
| growth); |
| want_inline = false; |
| } |
| else if (!leaf_node_p (callee) |
| && growth > 0) |
| { |
| if (dump_file) |
| fprintf (dump_file, " will not early inline: %s/%i->%s/%i, " |
| "callee is not leaf and code would grow by %i\n", |
| xstrdup (cgraph_node_name (e->caller)), e->caller->uid, |
| xstrdup (cgraph_node_name (callee)), callee->uid, |
| growth); |
| want_inline = false; |
| } |
| else if (growth > PARAM_VALUE (PARAM_EARLY_INLINING_INSNS)) |
| { |
| if (dump_file) |
| fprintf (dump_file, " will not early inline: %s/%i->%s/%i, " |
| "growth %i exceeds --param early-inlining-insns\n", |
| xstrdup (cgraph_node_name (e->caller)), e->caller->uid, |
| xstrdup (cgraph_node_name (callee)), callee->uid, |
| growth); |
| want_inline = false; |
| } |
| } |
| return want_inline; |
| } |
| |
| /* Return true if we are interested in inlining small function. |
| When REPORT is true, report reason to dump file. */ |
| |
| static bool |
| want_inline_small_function_p (struct cgraph_edge *e, bool report) |
| { |
| bool want_inline = true; |
| struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL); |
| |
| if (DECL_DISREGARD_INLINE_LIMITS (callee->symbol.decl)) |
| ; |
| else if (!DECL_DECLARED_INLINE_P (callee->symbol.decl) |
| && !flag_inline_small_functions) |
| { |
| e->inline_failed = CIF_FUNCTION_NOT_INLINE_CANDIDATE; |
| want_inline = false; |
| } |
| else |
| { |
| int growth = estimate_edge_growth (e); |
| inline_hints hints = estimate_edge_hints (e); |
| |
| if (growth <= 0) |
| ; |
| /* Apply MAX_INLINE_INSNS_SINGLE limit. Do not do so when |
| hints suggests that inlining given function is very profitable. */ |
| else if (DECL_DECLARED_INLINE_P (callee->symbol.decl) |
| && growth >= MAX_INLINE_INSNS_SINGLE |
| && !(hints & (INLINE_HINT_indirect_call |
| | INLINE_HINT_loop_iterations |
| | INLINE_HINT_loop_stride))) |
| { |
| e->inline_failed = CIF_MAX_INLINE_INSNS_SINGLE_LIMIT; |
| want_inline = false; |
| } |
| /* Before giving up based on fact that caller size will grow, allow |
| functions that are called few times and eliminating the offline |
| copy will lead to overall code size reduction. |
| Not all of these will be handled by subsequent inlining of functions |
| called once: in particular weak functions are not handled or funcitons |
| that inline to multiple calls but a lot of bodies is optimized out. |
| Finally we want to inline earlier to allow inlining of callbacks. |
| |
| This is slightly wrong on aggressive side: it is entirely possible |
| that function is called many times with a context where inlining |
| reduces code size and few times with a context where inlining increase |
| code size. Resoluting growth estimate will be negative even if it |
| would make more sense to keep offline copy and do not inline into the |
| call sites that makes the code size grow. |
| |
| When badness orders the calls in a way that code reducing calls come |
| first, this situation is not a problem at all: after inlining all |
| "good" calls, we will realize that keeping the function around is |
| better. */ |
| else if (growth <= MAX_INLINE_INSNS_SINGLE |
| /* Unlike for functions called once, we play unsafe with |
| COMDATs. We can allow that since we know functions |
| in consideration are small (and thus risk is small) and |
| moreover grow estimates already accounts that COMDAT |
| functions may or may not disappear when eliminated from |
| current unit. With good probability making aggressive |
| choice in all units is going to make overall program |
| smaller. |
| |
| Consequently we ask cgraph_can_remove_if_no_direct_calls_p |
| instead of |
| cgraph_will_be_removed_from_program_if_no_direct_calls */ |
| && !DECL_EXTERNAL (callee->symbol.decl) |
| && cgraph_can_remove_if_no_direct_calls_p (callee) |
| && estimate_growth (callee) <= 0) |
| ; |
| else if (!DECL_DECLARED_INLINE_P (callee->symbol.decl) |
| && !flag_inline_functions) |
| { |
| e->inline_failed = CIF_NOT_DECLARED_INLINED; |
| want_inline = false; |
| } |
| /* Apply MAX_INLINE_INSNS_AUTO limit for functions not declared inline |
| Upgrade it to MAX_INLINE_INSNS_SINGLE when hints suggests that |
| inlining given function is very profitable. */ |
| else if (!DECL_DECLARED_INLINE_P (callee->symbol.decl) |
| && growth >= ((hints & (INLINE_HINT_indirect_call |
| | INLINE_HINT_loop_iterations |
| | INLINE_HINT_loop_stride)) |
| ? MAX (MAX_INLINE_INSNS_AUTO, |
| MAX_INLINE_INSNS_SINGLE) |
| : MAX_INLINE_INSNS_AUTO)) |
| { |
| e->inline_failed = CIF_MAX_INLINE_INSNS_AUTO_LIMIT; |
| want_inline = false; |
| } |
| /* If call is cold, do not inline when function body would grow. */ |
| else if (!cgraph_maybe_hot_edge_p (e)) |
| { |
| e->inline_failed = CIF_UNLIKELY_CALL; |
| want_inline = false; |
| } |
| } |
| if (!want_inline && report) |
| report_inline_failed_reason (e); |
| return want_inline; |
| } |
| |
| /* EDGE is self recursive edge. |
| We hand two cases - when function A is inlining into itself |
| or when function A is being inlined into another inliner copy of function |
| A within function B. |
| |
| In first case OUTER_NODE points to the toplevel copy of A, while |
| in the second case OUTER_NODE points to the outermost copy of A in B. |
| |
| In both cases we want to be extra selective since |
| inlining the call will just introduce new recursive calls to appear. */ |
| |
| static bool |
| want_inline_self_recursive_call_p (struct cgraph_edge *edge, |
| struct cgraph_node *outer_node, |
| bool peeling, |
| int depth) |
| { |
| char const *reason = NULL; |
| bool want_inline = true; |
| int caller_freq = CGRAPH_FREQ_BASE; |
| int max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO); |
| |
| if (DECL_DECLARED_INLINE_P (edge->caller->symbol.decl)) |
| max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH); |
| |
| if (!cgraph_maybe_hot_edge_p (edge)) |
| { |
| reason = "recursive call is cold"; |
| want_inline = false; |
| } |
| else if (max_count && !outer_node->count) |
| { |
| reason = "not executed in profile"; |
| want_inline = false; |
| } |
| else if (depth > max_depth) |
| { |
| reason = "--param max-inline-recursive-depth exceeded."; |
| want_inline = false; |
| } |
| |
| if (outer_node->global.inlined_to) |
| caller_freq = outer_node->callers->frequency; |
| |
| if (!want_inline) |
| ; |
| /* Inlining of self recursive function into copy of itself within other function |
| is transformation similar to loop peeling. |
| |
| Peeling is profitable if we can inline enough copies to make probability |
| of actual call to the self recursive function very small. Be sure that |
| the probability of recursion is small. |
| |
| We ensure that the frequency of recursing is at most 1 - (1/max_depth). |
| This way the expected number of recision is at most max_depth. */ |
| else if (peeling) |
| { |
| int max_prob = CGRAPH_FREQ_BASE - ((CGRAPH_FREQ_BASE + max_depth - 1) |
| / max_depth); |
| int i; |
| for (i = 1; i < depth; i++) |
| max_prob = max_prob * max_prob / CGRAPH_FREQ_BASE; |
| if (max_count |
| && (edge->count * CGRAPH_FREQ_BASE / outer_node->count |
| >= max_prob)) |
| { |
| reason = "profile of recursive call is too large"; |
| want_inline = false; |
| } |
| if (!max_count |
| && (edge->frequency * CGRAPH_FREQ_BASE / caller_freq |
| >= max_prob)) |
| { |
| reason = "frequency of recursive call is too large"; |
| want_inline = false; |
| } |
| } |
| /* Recursive inlining, i.e. equivalent of unrolling, is profitable if recursion |
| depth is large. We reduce function call overhead and increase chances that |
| things fit in hardware return predictor. |
| |
| Recursive inlining might however increase cost of stack frame setup |
| actually slowing down functions whose recursion tree is wide rather than |
| deep. |
| |
| Deciding reliably on when to do recursive inlining without profile feedback |
| is tricky. For now we disable recursive inlining when probability of self |
| recursion is low. |
| |
| Recursive inlining of self recursive call within loop also results in large loop |
| depths that generally optimize badly. We may want to throttle down inlining |
| in those cases. In particular this seems to happen in one of libstdc++ rb tree |
| methods. */ |
| else |
| { |
| if (max_count |
| && (edge->count * 100 / outer_node->count |
| <= PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY))) |
| { |
| reason = "profile of recursive call is too small"; |
| want_inline = false; |
| } |
| else if (!max_count |
| && (edge->frequency * 100 / caller_freq |
| <= PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY))) |
| { |
| reason = "frequency of recursive call is too small"; |
| want_inline = false; |
| } |
| } |
| if (!want_inline && dump_file) |
| fprintf (dump_file, " not inlining recursively: %s\n", reason); |
| return want_inline; |
| } |
| |
| /* Return true when NODE has caller other than EDGE. |
| Worker for cgraph_for_node_and_aliases. */ |
| |
| static bool |
| check_caller_edge (struct cgraph_node *node, void *edge) |
| { |
| return (node->callers |
| && node->callers != edge); |
| } |
| |
| |
| /* Decide if NODE is called once inlining it would eliminate need |
| for the offline copy of function. */ |
| |
| static bool |
| want_inline_function_called_once_p (struct cgraph_node *node) |
| { |
| struct cgraph_node *function = cgraph_function_or_thunk_node (node, NULL); |
| /* Already inlined? */ |
| if (function->global.inlined_to) |
| return false; |
| /* Zero or more then one callers? */ |
| if (!node->callers |
| || node->callers->next_caller) |
| return false; |
| /* Maybe other aliases has more direct calls. */ |
| if (cgraph_for_node_and_aliases (node, check_caller_edge, node->callers, true)) |
| return false; |
| /* Recursive call makes no sense to inline. */ |
| if (cgraph_edge_recursive_p (node->callers)) |
| return false; |
| /* External functions are not really in the unit, so inlining |
| them when called once would just increase the program size. */ |
| if (DECL_EXTERNAL (function->symbol.decl)) |
| return false; |
| /* Offline body must be optimized out. */ |
| if (!cgraph_will_be_removed_from_program_if_no_direct_calls (function)) |
| return false; |
| if (!can_inline_edge_p (node->callers, true)) |
| return false; |
| 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) * edge->frequency |
| + CGRAPH_FREQ_BASE / 2) / 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 |
| metrics may accurately depend on values such as number of inlinable callers |
| of the function or function body size. */ |
| |
| static int |
| edge_badness (struct cgraph_edge *edge, bool dump) |
| { |
| gcov_type badness; |
| int growth, time_growth; |
| struct cgraph_node *callee = cgraph_function_or_thunk_node (edge->callee, |
| NULL); |
| struct inline_summary *callee_info = inline_summary (callee); |
| inline_hints hints; |
| |
| if (DECL_DISREGARD_INLINE_LIMITS (callee->symbol.decl)) |
| return INT_MIN; |
| |
| growth = estimate_edge_growth (edge); |
| time_growth = estimate_edge_time (edge); |
| hints = estimate_edge_hints (edge); |
| |
| if (dump) |
| { |
| fprintf (dump_file, " Badness calculation for %s -> %s\n", |
| xstrdup (cgraph_node_name (edge->caller)), |
| xstrdup (cgraph_node_name (callee))); |
| fprintf (dump_file, " size growth %i, time growth %i ", |
| growth, |
| time_growth); |
| dump_inline_hints (dump_file, hints); |
| fprintf (dump_file, "\n"); |
| } |
| |
| /* Always prefer inlining saving code size. */ |
| if (growth <= 0) |
| { |
| badness = INT_MIN / 2 + growth; |
| if (dump) |
| fprintf (dump_file, " %i: Growth %i <= 0\n", (int) badness, |
| growth); |
| } |
| |
| /* When profiling is available, compute badness as: |
| |
| relative_edge_count * relative_time_benefit |
| goodness = ------------------------------------------- |
| edge_growth |
| badness = -goodness |
| |
| The fraction is upside down, because on edge counts and time beneits |
| the bounds are known. Edge growth is essentially unlimited. */ |
| |
| else if (max_count) |
| { |
| int relbenefit = relative_time_benefit (callee_info, edge, time_growth); |
| badness = |
| ((int) |
| ((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. */ |
| gcc_assert (max_count >= edge->count); |
| if (dump) |
| { |
| fprintf (dump_file, |
| " %i (relative %f): profile info. Relative count %f" |
| " * Relative benefit %f\n", |
| (int) badness, (double) badness / INT_MIN, |
| (double) edge->count / max_count, |
| relbenefit * 100 / 256.0); |
| } |
| } |
| |
| /* When function local profile is available. Compute badness as: |
| |
| |
| growth_of_callee |
| badness = -------------------------------------- + growth_for-all |
| relative_time_benefit * edge_frequency |
| |
| */ |
| else if (flag_guess_branch_prob) |
| { |
| int div = edge->frequency * (1<<10) / CGRAPH_FREQ_MAX; |
| |
| 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. |
| |
| Fixed point arithmetic with point at 8th bit. */ |
| badness = ((gcov_type)growth) * (1<<(19+8)); |
| 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. */ |
| if (badness > INT_MAX / 2) |
| { |
| badness = INT_MAX / 2; |
| if (dump) |
| fprintf (dump_file, "Badness overflow\n"); |
| } |
| if (hints & (INLINE_HINT_indirect_call |
| | INLINE_HINT_loop_iterations |
| | INLINE_HINT_loop_stride)) |
| badness /= 8; |
| if (dump) |
| { |
| fprintf (dump_file, |
| " %i: guessed profile. frequency %f," |
| " benefit %f%%, divisor %i\n", |
| (int) badness, (double)edge->frequency / CGRAPH_FREQ_BASE, |
| relative_time_benefit (callee_info, edge, time_growth) * 100 / 256.0, div); |
| } |
| } |
| /* When function local profile is not available or it does not give |
| useful information (ie frequency is zero), base the cost on |
| loop nest and overall size growth, so we optimize for overall number |
| of functions fully inlined in program. */ |
| else |
| { |
| int nest = MIN (inline_edge_summary (edge)->loop_depth, 8); |
| badness = growth * 256; |
| |
| /* Decrease badness if call is nested. */ |
| if (badness > 0) |
| badness >>= nest; |
| else |
| { |
| badness <<= nest; |
| } |
| if (dump) |
| fprintf (dump_file, " %i: no profile. nest %i\n", (int) badness, |
| nest); |
| } |
| |
| /* Ensure that we did not overflow in all the fixed point math above. */ |
| gcc_assert (badness >= INT_MIN); |
| gcc_assert (badness <= INT_MAX - 1); |
| /* Make recursive inlining happen always after other inlining is done. */ |
| if (cgraph_edge_recursive_p (edge)) |
| return badness + 1; |
| else |
| return badness; |
| } |
| |
| /* Recompute badness of EDGE and update its key in HEAP if needed. */ |
| static inline void |
| update_edge_key (fibheap_t heap, struct cgraph_edge *edge) |
| { |
| int badness = edge_badness (edge, false); |
| if (edge->aux) |
| { |
| fibnode_t n = (fibnode_t) edge->aux; |
| gcc_checking_assert (n->data == edge); |
| |
| /* fibheap_replace_key only decrease the keys. |
| When we increase the key we do not update heap |
| and instead re-insert the element once it becomes |
| a minimum of heap. */ |
| if (badness < n->key) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, |
| " decreasing badness %s/%i -> %s/%i, %i to %i\n", |
| xstrdup (cgraph_node_name (edge->caller)), |
| edge->caller->uid, |
| xstrdup (cgraph_node_name (edge->callee)), |
| edge->callee->uid, |
| (int)n->key, |
| badness); |
| } |
| fibheap_replace_key (heap, n, badness); |
| gcc_checking_assert (n->key == badness); |
| } |
| } |
| else |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, |
| " enqueuing call %s/%i -> %s/%i, badness %i\n", |
| xstrdup (cgraph_node_name (edge->caller)), |
| edge->caller->uid, |
| xstrdup (cgraph_node_name (edge->callee)), |
| edge->callee->uid, |
| badness); |
| } |
| edge->aux = fibheap_insert (heap, badness, edge); |
| } |
| } |
| |
| |
| /* NODE was inlined. |
| All caller edges needs to be resetted because |
| size estimates change. Similarly callees needs reset |
| because better context may be known. */ |
| |
| static void |
| reset_edge_caches (struct cgraph_node *node) |
| { |
| struct cgraph_edge *edge; |
| struct cgraph_edge *e = node->callees; |
| struct cgraph_node *where = node; |
| int i; |
| struct ipa_ref *ref; |
| |
| if (where->global.inlined_to) |
| where = where->global.inlined_to; |
| |
| /* WHERE body size has changed, the cached growth is invalid. */ |
| reset_node_growth_cache (where); |
| |
| for (edge = where->callers; edge; edge = edge->next_caller) |
| if (edge->inline_failed) |
| reset_edge_growth_cache (edge); |
| for (i = 0; ipa_ref_list_referring_iterate (&where->symbol.ref_list, |
| i, ref); i++) |
| if (ref->use == IPA_REF_ALIAS) |
| reset_edge_caches (ipa_ref_referring_node (ref)); |
| |
| if (!e) |
| return; |
| |
| while (true) |
| if (!e->inline_failed && e->callee->callees) |
| e = e->callee->callees; |
| else |
| { |
| if (e->inline_failed) |
| reset_edge_growth_cache (e); |
| if (e->next_callee) |
| e = e->next_callee; |
| else |
| { |
| do |
| { |
| if (e->caller == node) |
| return; |
| e = e->caller->callers; |
| } |
| while (!e->next_callee); |
| e = e->next_callee; |
| } |
| } |
| } |
| |
| /* Recompute HEAP nodes for each of caller of NODE. |
| UPDATED_NODES track nodes we already visited, to avoid redundant work. |
| When CHECK_INLINABLITY_FOR is set, re-check for specified edge that |
| it is inlinable. Otherwise check all edges. */ |
| |
| static void |
| update_caller_keys (fibheap_t heap, struct cgraph_node *node, |
| bitmap updated_nodes, |
| struct cgraph_edge *check_inlinablity_for) |
| { |
| struct cgraph_edge *edge; |
| int i; |
| struct ipa_ref *ref; |
| |
| if ((!node->alias && !inline_summary (node)->inlinable) |
| || cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE |
| || node->global.inlined_to) |
| return; |
| if (!bitmap_set_bit (updated_nodes, node->uid)) |
| return; |
| |
| for (i = 0; ipa_ref_list_referring_iterate (&node->symbol.ref_list, |
| i, ref); i++) |
| if (ref->use == IPA_REF_ALIAS) |
| { |
| struct cgraph_node *alias = ipa_ref_referring_node (ref); |
| update_caller_keys (heap, alias, updated_nodes, check_inlinablity_for); |
| } |
| |
| for (edge = node->callers; edge; edge = edge->next_caller) |
| if (edge->inline_failed) |
| { |
| if (!check_inlinablity_for |
| || check_inlinablity_for == edge) |
| { |
| if (can_inline_edge_p (edge, false) |
| && want_inline_small_function_p (edge, false)) |
| update_edge_key (heap, edge); |
| else if (edge->aux) |
| { |
| report_inline_failed_reason (edge); |
| fibheap_delete_node (heap, (fibnode_t) edge->aux); |
| edge->aux = NULL; |
| } |
| } |
| else if (edge->aux) |
| update_edge_key (heap, edge); |
| } |
| } |
| |
| /* Recompute HEAP nodes for each uninlined call in NODE. |
| This is used when we know that edge badnesses are going only to increase |
| (we introduced new call site) and thus all we need is to insert newly |
| created edges into heap. */ |
| |
| static void |
| update_callee_keys (fibheap_t heap, struct cgraph_node *node, |
| bitmap updated_nodes) |
| { |
| struct cgraph_edge *e = node->callees; |
| |
| if (!e) |
| return; |
| while (true) |
| if (!e->inline_failed && e->callee->callees) |
| e = e->callee->callees; |
| else |
| { |
| enum availability avail; |
| struct cgraph_node *callee; |
| /* We do not reset callee growth cache here. Since we added a new call, |
| growth chould have just increased and consequentely badness metric |
| don't need updating. */ |
| if (e->inline_failed |
| && (callee = cgraph_function_or_thunk_node (e->callee, &avail)) |
| && inline_summary (callee)->inlinable |
| && cgraph_function_body_availability (callee) >= AVAIL_AVAILABLE |
| && !bitmap_bit_p (updated_nodes, callee->uid)) |
| { |
| if (can_inline_edge_p (e, false) |
| && want_inline_small_function_p (e, false)) |
| update_edge_key (heap, e); |
| else if (e->aux) |
| { |
| report_inline_failed_reason (e); |
| fibheap_delete_node (heap, (fibnode_t) e->aux); |
| e->aux = NULL; |
| } |
| } |
| if (e->next_callee) |
| e = e->next_callee; |
| else |
| { |
| do |
| { |
| if (e->caller == node) |
| return; |
| e = e->caller->callers; |
| } |
| while (!e->next_callee); |
| e = e->next_callee; |
| } |
| } |
| } |
| |
| /* Enqueue all recursive calls from NODE into priority queue depending on |
| how likely we want to recursively inline the call. */ |
| |
| static void |
| lookup_recursive_calls (struct cgraph_node *node, struct cgraph_node *where, |
| fibheap_t heap) |
| { |
| struct cgraph_edge *e; |
| enum availability avail; |
| |
| for (e = where->callees; e; e = e->next_callee) |
| if (e->callee == node |
| || (cgraph_function_or_thunk_node (e->callee, &avail) == node |
| && avail > AVAIL_OVERWRITABLE)) |
| { |
| /* When profile feedback is available, prioritize by expected number |
| of calls. */ |
| fibheap_insert (heap, |
| !max_count ? -e->frequency |
| : -(e->count / ((max_count + (1<<24) - 1) / (1<<24))), |
| e); |
| } |
| for (e = where->callees; e; e = e->next_callee) |
| if (!e->inline_failed) |
| lookup_recursive_calls (node, e->callee, heap); |
| } |
| |
| /* Decide on recursive inlining: in the case function has recursive calls, |
| inline until body size reaches given argument. If any new indirect edges |
| are discovered in the process, add them to *NEW_EDGES, unless NEW_EDGES |
| is NULL. */ |
| |
| static bool |
| recursive_inlining (struct cgraph_edge *edge, |
| VEC (cgraph_edge_p, heap) **new_edges) |
| { |
| int limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO); |
| fibheap_t heap; |
| struct cgraph_node *node; |
| struct cgraph_edge *e; |
| struct cgraph_node *master_clone = NULL, *next; |
| int depth = 0; |
| int n = 0; |
| |
| node = edge->caller; |
| if (node->global.inlined_to) |
| node = node->global.inlined_to; |
| |
| if (DECL_DECLARED_INLINE_P (node->symbol.decl)) |
| limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE); |
| |
| /* Make sure that function is small enough to be considered for inlining. */ |
| if (estimate_size_after_inlining (node, edge) >= limit) |
| return false; |
| heap = fibheap_new (); |
| lookup_recursive_calls (node, node, heap); |
| if (fibheap_empty (heap)) |
| { |
| fibheap_delete (heap); |
| return false; |
| } |
| |
| if (dump_file) |
| fprintf (dump_file, |
| " Performing recursive inlining on %s\n", |
| cgraph_node_name (node)); |
| |
| /* Do the inlining and update list of recursive call during process. */ |
| while (!fibheap_empty (heap)) |
| { |
| struct cgraph_edge *curr |
| = (struct cgraph_edge *) fibheap_extract_min (heap); |
| struct cgraph_node *cnode; |
| |
| if (estimate_size_after_inlining (node, curr) > limit) |
| break; |
| |
| if (!can_inline_edge_p (curr, true)) |
| continue; |
| |
| depth = 1; |
| for (cnode = curr->caller; |
| cnode->global.inlined_to; cnode = cnode->callers->caller) |
| if (node->symbol.decl |
| == cgraph_function_or_thunk_node (curr->callee, NULL)->symbol.decl) |
| depth++; |
| |
| if (!want_inline_self_recursive_call_p (curr, node, false, depth)) |
| continue; |
| |
| if (dump_file) |
| { |
| fprintf (dump_file, |
| " Inlining call of depth %i", depth); |
| if (node->count) |
| { |
| fprintf (dump_file, " called approx. %.2f times per call", |
| (double)curr->count / node->count); |
| } |
| fprintf (dump_file, "\n"); |
| } |
| if (!master_clone) |
| { |
| /* We need original clone to copy around. */ |
| master_clone = cgraph_clone_node (node, node->symbol.decl, |
| node->count, CGRAPH_FREQ_BASE, |
| false, NULL, true); |
| for (e = master_clone->callees; e; e = e->next_callee) |
| if (!e->inline_failed) |
| clone_inlined_nodes (e, true, false, NULL); |
| } |
| |
| cgraph_redirect_edge_callee (curr, master_clone); |
| inline_call (curr, false, new_edges, &overall_size, true); |
| lookup_recursive_calls (node, curr->callee, heap); |
| n++; |
| } |
| |
| if (!fibheap_empty (heap) && dump_file) |
| fprintf (dump_file, " Recursive inlining growth limit met.\n"); |
| fibheap_delete (heap); |
| |
| if (!master_clone) |
| return false; |
| |
| if (dump_file) |
| fprintf (dump_file, |
| "\n Inlined %i times, " |
| "body grown from size %i to %i, time %i to %i\n", n, |
| inline_summary (master_clone)->size, inline_summary (node)->size, |
| inline_summary (master_clone)->time, inline_summary (node)->time); |
| |
| /* Remove master clone we used for inlining. We rely that clones inlined |
| into master clone gets queued just before master clone so we don't |
| need recursion. */ |
| for (node = cgraph_first_function (); node != master_clone; |
| node = next) |
| { |
| next = cgraph_next_function (node); |
| if (node->global.inlined_to == master_clone) |
| cgraph_remove_node (node); |
| } |
| cgraph_remove_node (master_clone); |
| return true; |
| } |
| |
| |
| /* Given whole compilation unit estimate of INSNS, compute how large we can |
| allow the unit to grow. */ |
| |
| static int |
| compute_max_insns (int insns) |
| { |
| int max_insns = insns; |
| if (max_insns < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS)) |
| max_insns = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS); |
| |
| return ((HOST_WIDEST_INT) max_insns |
| * (100 + PARAM_VALUE (PARAM_INLINE_UNIT_GROWTH)) / 100); |
| } |
| |
| |
| /* Compute badness of all edges in NEW_EDGES and add them to the HEAP. */ |
| |
| static void |
| add_new_edges_to_heap (fibheap_t heap, VEC (cgraph_edge_p, heap) *new_edges) |
| { |
| while (VEC_length (cgraph_edge_p, new_edges) > 0) |
| { |
| struct cgraph_edge *edge = VEC_pop (cgraph_edge_p, new_edges); |
| |
| gcc_assert (!edge->aux); |
| if (edge->inline_failed |
| && can_inline_edge_p (edge, true) |
| && want_inline_small_function_p (edge, true)) |
| edge->aux = fibheap_insert (heap, edge_badness (edge, false), edge); |
| } |
| } |
| |
| |
| /* We use greedy algorithm for inlining of small functions: |
| All inline candidates are put into prioritized heap ordered in |
| increasing badness. |
| |
| The inlining of small functions is bounded by unit growth parameters. */ |
| |
| static void |
| inline_small_functions (void) |
| { |
| struct cgraph_node *node; |
| struct cgraph_edge *edge; |
| fibheap_t edge_heap = fibheap_new (); |
| bitmap updated_nodes = BITMAP_ALLOC (NULL); |
| int min_size, max_size; |
| VEC (cgraph_edge_p, heap) *new_indirect_edges = NULL; |
| int initial_size = 0; |
| |
| if (flag_indirect_inlining) |
| new_indirect_edges = VEC_alloc (cgraph_edge_p, heap, 8); |
| |
| if (dump_file) |
| fprintf (dump_file, |
| "\nDeciding on inlining of small functions. Starting with size %i.\n", |
| initial_size); |
| |
| /* Compute overall unit size and other global parameters used by badness |
| metrics. */ |
| |
| max_count = 0; |
| initialize_growth_caches (); |
| |
| FOR_EACH_DEFINED_FUNCTION (node) |
| if (!node->global.inlined_to) |
| { |
| if (cgraph_function_with_gimple_body_p (node) |
| || node->thunk.thunk_p) |
| { |
| struct inline_summary *info = inline_summary (node); |
| |
| if (!DECL_EXTERNAL (node->symbol.decl)) |
| initial_size += info->size; |
| } |
| |
| for (edge = node->callers; edge; edge = edge->next_caller) |
| if (max_count < edge->count) |
| max_count = edge->count; |
| } |
| |
| overall_size = initial_size; |
| max_size = compute_max_insns (overall_size); |
| min_size = overall_size; |
| |
| /* Populate the heeap with all edges we might inline. */ |
| |
| FOR_EACH_DEFINED_FUNCTION (node) |
| if (!node->global.inlined_to) |
| { |
| if (dump_file) |
| fprintf (dump_file, "Enqueueing calls of %s/%i.\n", |
| cgraph_node_name (node), node->uid); |
| |
| for (edge = node->callers; edge; edge = edge->next_caller) |
| if (edge->inline_failed |
| && can_inline_edge_p (edge, true) |
| && want_inline_small_function_p (edge, true) |
| && edge->inline_failed) |
| { |
| gcc_assert (!edge->aux); |
| update_edge_key (edge_heap, edge); |
| } |
| } |
| |
| gcc_assert (in_lto_p |
| || !max_count |
| || (profile_info && flag_branch_probabilities)); |
| |
| while (!fibheap_empty (edge_heap)) |
| { |
| int old_size = overall_size; |
| struct cgraph_node *where, *callee; |
| int badness = fibheap_min_key (edge_heap); |
| int current_badness; |
| int cached_badness; |
| int growth; |
| |
| edge = (struct cgraph_edge *) fibheap_extract_min (edge_heap); |
| gcc_assert (edge->aux); |
| edge->aux = NULL; |
| if (!edge->inline_failed) |
| continue; |
| |
| /* Be sure that caches are maintained consistent. |
| We can not make this ENABLE_CHECKING only because it cause different |
| updates of the fibheap queue. */ |
| cached_badness = edge_badness (edge, false); |
| reset_edge_growth_cache (edge); |
| reset_node_growth_cache (edge->callee); |
| |
| /* When updating the edge costs, we only decrease badness in the keys. |
| Increases of badness are handled lazilly; when we see key with out |
| of date value on it, we re-insert it now. */ |
| current_badness = edge_badness (edge, false); |
| gcc_assert (cached_badness == current_badness); |
| gcc_assert (current_badness >= badness); |
| if (current_badness != badness) |
| { |
| edge->aux = fibheap_insert (edge_heap, current_badness, edge); |
| continue; |
| } |
| |
| if (!can_inline_edge_p (edge, true)) |
| continue; |
| |
| callee = cgraph_function_or_thunk_node (edge->callee, NULL); |
| growth = estimate_edge_growth (edge); |
| if (dump_file) |
| { |
| fprintf (dump_file, |
| "\nConsidering %s with %i size\n", |
| cgraph_node_name (callee), |
| inline_summary (callee)->size); |
| fprintf (dump_file, |
| " to be inlined into %s in %s:%i\n" |
| " Estimated growth after inlined into all is %+i insns.\n" |
| " Estimated badness is %i, frequency %.2f.\n", |
| cgraph_node_name (edge->caller), |
| flag_wpa ? "unknown" |
| : gimple_filename ((const_gimple) edge->call_stmt), |
| flag_wpa ? -1 |
| : gimple_lineno ((const_gimple) edge->call_stmt), |
| estimate_growth (callee), |
| badness, |
| edge->frequency / (double)CGRAPH_FREQ_BASE); |
| if (edge->count) |
| fprintf (dump_file," Called "HOST_WIDEST_INT_PRINT_DEC"x\n", |
| edge->count); |
| if (dump_flags & TDF_DETAILS) |
| edge_badness (edge, true); |
| } |
| |
| if (overall_size + growth > max_size |
| && !DECL_DISREGARD_INLINE_LIMITS (callee->symbol.decl)) |
| { |
| edge->inline_failed = CIF_INLINE_UNIT_GROWTH_LIMIT; |
| report_inline_failed_reason (edge); |
| continue; |
| } |
| |
| if (!want_inline_small_function_p (edge, true)) |
| continue; |
| |
| /* Heuristics for inlining small functions works poorly for |
| recursive calls where we do efect similar to loop unrolling. |
| When inliing such edge seems profitable, leave decision on |
| specific inliner. */ |
| if (cgraph_edge_recursive_p (edge)) |
| { |
| where = edge->caller; |
| if (where->global.inlined_to) |
| where = where->global.inlined_to; |
| if (!recursive_inlining (edge, |
| flag_indirect_inlining |
| ? &new_indirect_edges : NULL)) |
| { |
| edge->inline_failed = CIF_RECURSIVE_INLINING; |
| continue; |
| } |
| reset_edge_caches (where); |
| /* Recursive inliner inlines all recursive calls of the function |
| at once. Consequently we need to update all callee keys. */ |
| if (flag_indirect_inlining) |
| add_new_edges_to_heap (edge_heap, new_indirect_edges); |
| update_callee_keys (edge_heap, where, updated_nodes); |
| } |
| else |
| { |
| struct cgraph_node *outer_node = NULL; |
| int depth = 0; |
| |
| /* Consider the case where self recursive function A is inlined into B. |
| This is desired optimization in some cases, since it leads to effect |
| similar of loop peeling and we might completely optimize out the |
| recursive call. However we must be extra selective. */ |
| |
| where = edge->caller; |
| while (where->global.inlined_to) |
| { |
| if (where->symbol.decl == callee->symbol.decl) |
| outer_node = where, depth++; |
| where = where->callers->caller; |
| } |
| if (outer_node |
| && !want_inline_self_recursive_call_p (edge, outer_node, |
| true, depth)) |
| { |
| edge->inline_failed |
| = (DECL_DISREGARD_INLINE_LIMITS (edge->callee->symbol.decl) |
| ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED); |
| continue; |
| } |
| else if (depth && dump_file) |
| fprintf (dump_file, " Peeling recursion with depth %i\n", depth); |
| |
| gcc_checking_assert (!callee->global.inlined_to); |
| inline_call (edge, true, &new_indirect_edges, &overall_size, true); |
| if (flag_indirect_inlining) |
| add_new_edges_to_heap (edge_heap, new_indirect_edges); |
| |
| reset_edge_caches (edge->callee); |
| reset_node_growth_cache (callee); |
| |
| update_callee_keys (edge_heap, edge->callee, updated_nodes); |
| } |
| where = edge->caller; |
| if (where->global.inlined_to) |
| where = where->global.inlined_to; |
| |
| /* Our profitability metric can depend on local properties |
| such as number of inlinable calls and size of the function body. |
| After inlining these properties might change for the function we |
| inlined into (since it's body size changed) and for the functions |
| called by function we inlined (since number of it inlinable callers |
| might change). */ |
| update_caller_keys (edge_heap, where, updated_nodes, NULL); |
| bitmap_clear (updated_nodes); |
| |
| if (dump_file) |
| { |
| fprintf (dump_file, |
| " Inlined into %s which now has time %i and size %i," |
| "net change of %+i.\n", |
| cgraph_node_name (edge->caller), |
| inline_summary (edge->caller)->time, |
| inline_summary (edge->caller)->size, |
| overall_size - old_size); |
| } |
| if (min_size > overall_size) |
| { |
| min_size = overall_size; |
| max_size = compute_max_insns (min_size); |
| |
| if (dump_file) |
| fprintf (dump_file, "New minimal size reached: %i\n", min_size); |
| } |
| } |
| |
| free_growth_caches (); |
| if (new_indirect_edges) |
| VEC_free (cgraph_edge_p, heap, new_indirect_edges); |
| fibheap_delete (edge_heap); |
| if (dump_file) |
| fprintf (dump_file, |
| "Unit growth for small function inlining: %i->%i (%i%%)\n", |
| initial_size, overall_size, |
| initial_size ? overall_size * 100 / (initial_size) - 100: 0); |
| BITMAP_FREE (updated_nodes); |
| } |
| |
| /* Flatten NODE. Performed both during early inlining and |
| at IPA inlining time. */ |
| |
| static void |
| flatten_function (struct cgraph_node *node, bool early) |
| { |
| struct cgraph_edge *e; |
| |
| /* We shouldn't be called recursively when we are being processed. */ |
| gcc_assert (node->symbol.aux == NULL); |
| |
| node->symbol.aux = (void *) node; |
| |
| for (e = node->callees; e; e = e->next_callee) |
| { |
| struct cgraph_node *orig_callee; |
| struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL); |
| |
| /* We've hit cycle? It is time to give up. */ |
| if (callee->symbol.aux) |
| { |
| if (dump_file) |
| fprintf (dump_file, |
| "Not inlining %s into %s to avoid cycle.\n", |
| xstrdup (cgraph_node_name (callee)), |
| xstrdup (cgraph_node_name (e->caller))); |
| e->inline_failed = CIF_RECURSIVE_INLINING; |
| continue; |
| } |
| |
| /* When the edge is already inlined, we just need to recurse into |
| it in order to fully flatten the leaves. */ |
| if (!e->inline_failed) |
| { |
| flatten_function (callee, early); |
| continue; |
| } |
| |
| /* Flatten attribute needs to be processed during late inlining. For |
| extra code quality we however do flattening during early optimization, |
| too. */ |
| if (!early |
| ? !can_inline_edge_p (e, true) |
| : !can_early_inline_edge_p (e)) |
| continue; |
| |
| if (cgraph_edge_recursive_p (e)) |
| { |
| if (dump_file) |
| fprintf (dump_file, "Not inlining: recursive call.\n"); |
| continue; |
| } |
| |
| if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node->symbol.decl)) |
| != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->symbol.decl))) |
| { |
| if (dump_file) |
| fprintf (dump_file, "Not inlining: SSA form does not match.\n"); |
| continue; |
| } |
| |
| /* Inline the edge and flatten the inline clone. Avoid |
| recursing through the original node if the node was cloned. */ |
| if (dump_file) |
| fprintf (dump_file, " Inlining %s into %s.\n", |
| xstrdup (cgraph_node_name (callee)), |
| xstrdup (cgraph_node_name (e->caller))); |
| orig_callee = callee; |
| inline_call (e, true, NULL, NULL, false); |
| if (e->callee != orig_callee) |
| orig_callee->symbol.aux = (void *) node; |
| flatten_function (e->callee, early); |
| if (e->callee != orig_callee) |
| orig_callee->symbol.aux = NULL; |
| } |
| |
| node->symbol.aux = NULL; |
| if (!node->global.inlined_to) |
| inline_update_overall_summary (node); |
| } |
| |
| /* Decide on the inlining. We do so in the topological order to avoid |
| expenses on updating data structures. */ |
| |
| static unsigned int |
| ipa_inline (void) |
| { |
| struct cgraph_node *node; |
| int nnodes; |
| struct cgraph_node **order = |
| XCNEWVEC (struct cgraph_node *, cgraph_n_nodes); |
| int i; |
| |
| if (in_lto_p && optimize) |
| ipa_update_after_lto_read (); |
| |
| if (dump_file) |
| dump_inline_summaries (dump_file); |
| |
| nnodes = ipa_reverse_postorder (order); |
| |
| FOR_EACH_FUNCTION (node) |
| node->symbol.aux = 0; |
| |
| if (dump_file) |
| fprintf (dump_file, "\nFlattening functions:\n"); |
| |
| /* In the first pass handle functions to be flattened. Do this with |
| a priority so none of our later choices will make this impossible. */ |
| for (i = nnodes - 1; i >= 0; i--) |
| { |
| node = order[i]; |
| |
| /* Handle nodes to be flattened. |
| Ideally when processing callees we stop inlining at the |
| entry of cycles, possibly cloning that entry point and |
| try to flatten itself turning it into a self-recursive |
| function. */ |
| if (lookup_attribute ("flatten", |
| DECL_ATTRIBUTES (node->symbol.decl)) != NULL) |
| { |
| if (dump_file) |
| fprintf (dump_file, |
| "Flattening %s\n", cgraph_node_name (node)); |
| flatten_function (node, false); |
| } |
| } |
| |
| inline_small_functions (); |
| symtab_remove_unreachable_nodes (true, dump_file); |
| free (order); |
| |
| /* We already perform some inlining of functions called once during |
| inlining small functions above. After unreachable nodes are removed, |
| we still might do a quick check that nothing new is found. */ |
| if (flag_inline_functions_called_once) |
| { |
| int cold; |
| if (dump_file) |
| fprintf (dump_file, "\nDeciding on functions called once:\n"); |
| |
| /* Inlining one function called once has good chance of preventing |
| inlining other function into the same callee. Ideally we should |
| work in priority order, but probably inlining hot functions first |
| is good cut without the extra pain of maintaining the queue. |
| |
| ??? this is not really fitting the bill perfectly: inlining function |
| into callee often leads to better optimization of callee due to |
| increased context for optimization. |
| For example if main() function calls a function that outputs help |
| and then function that does the main optmization, we should inline |
| the second with priority even if both calls are cold by themselves. |
| |
| We probably want to implement new predicate replacing our use of |
| maybe_hot_edge interpreted as maybe_hot_edge || callee is known |
| to be hot. */ |
| for (cold = 0; cold <= 1; cold ++) |
| { |
| FOR_EACH_DEFINED_FUNCTION (node) |
| { |
| if (want_inline_function_called_once_p (node) |
| && (cold |
| || cgraph_maybe_hot_edge_p (node->callers))) |
| { |
| struct cgraph_node *caller = node->callers->caller; |
| |
| if (dump_file) |
| { |
| fprintf (dump_file, |
| "\nInlining %s size %i.\n", |
| cgraph_node_name (node), |
| inline_summary (node)->size); |
| fprintf (dump_file, |
| " Called once from %s %i insns.\n", |
| cgraph_node_name (node->callers->caller), |
| inline_summary (node->callers->caller)->size); |
| } |
| |
| inline_call (node->callers, true, NULL, NULL, true); |
| if (dump_file) |
| fprintf (dump_file, |
| " Inlined into %s which now has %i size\n", |
| cgraph_node_name (caller), |
| inline_summary (caller)->size); |
| } |
| } |
| } |
| } |
| |
| /* Free ipa-prop structures if they are no longer needed. */ |
| if (optimize) |
| ipa_free_all_structures_after_iinln (); |
| |
| if (dump_file) |
| fprintf (dump_file, |
| "\nInlined %i calls, eliminated %i functions\n\n", |
| ncalls_inlined, nfunctions_inlined); |
| |
| if (dump_file) |
| dump_inline_summaries (dump_file); |
| /* In WPA we use inline summaries for partitioning process. */ |
| if (!flag_wpa) |
| inline_free_summary (); |
| return 0; |
| } |
| |
| /* Inline always-inline function calls in NODE. */ |
| |
| static bool |
| inline_always_inline_functions (struct cgraph_node *node) |
| { |
| struct cgraph_edge *e; |
| bool inlined = false; |
| |
| for (e = node->callees; e; e = e->next_callee) |
| { |
| struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL); |
| if (!DECL_DISREGARD_INLINE_LIMITS (callee->symbol.decl)) |
| continue; |
| |
| if (cgraph_edge_recursive_p (e)) |
| { |
| if (dump_file) |
| fprintf (dump_file, " Not inlining recursive call to %s.\n", |
| cgraph_node_name (e->callee)); |
| e->inline_failed = CIF_RECURSIVE_INLINING; |
| continue; |
| } |
| |
| if (!can_early_inline_edge_p (e)) |
| continue; |
| |
| if (dump_file) |
| fprintf (dump_file, " Inlining %s into %s (always_inline).\n", |
| xstrdup (cgraph_node_name (e->callee)), |
| xstrdup (cgraph_node_name (e->caller))); |
| inline_call (e, true, NULL, NULL, false); |
| inlined = true; |
| } |
| if (inlined) |
| inline_update_overall_summary (node); |
| |
| return inlined; |
| } |
| |
| /* Decide on the inlining. We do so in the topological order to avoid |
| expenses on updating data structures. */ |
| |
| static bool |
| early_inline_small_functions (struct cgraph_node *node) |
| { |
| struct cgraph_edge *e; |
| bool inlined = false; |
| |
| for (e = node->callees; e; e = e->next_callee) |
| { |
| struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL); |
| if (!inline_summary (callee)->inlinable |
| || !e->inline_failed) |
| continue; |
| |
| /* Do not consider functions not declared inline. */ |
| if (!DECL_DECLARED_INLINE_P (callee->symbol.decl) |
| && !flag_inline_small_functions |
| && !flag_inline_functions) |
| continue; |
| |
| if (dump_file) |
| fprintf (dump_file, "Considering inline candidate %s.\n", |
| cgraph_node_name (callee)); |
| |
| if (!can_early_inline_edge_p (e)) |
| continue; |
| |
| if (cgraph_edge_recursive_p (e)) |
| { |
| if (dump_file) |
| fprintf (dump_file, " Not inlining: recursive call.\n"); |
| continue; |
| } |
| |
| if (!want_early_inline_function_p (e)) |
| continue; |
| |
| if (dump_file) |
| fprintf (dump_file, " Inlining %s into %s.\n", |
| xstrdup (cgraph_node_name (callee)), |
| xstrdup (cgraph_node_name (e->caller))); |
| inline_call (e, true, NULL, NULL, true); |
| inlined = true; |
| } |
| |
| return inlined; |
| } |
| |
| /* Do inlining of small functions. Doing so early helps profiling and other |
| passes to be somewhat more effective and avoids some code duplication in |
| later real inlining pass for testcases with very many function calls. */ |
| static unsigned int |
| early_inliner (void) |
| { |
| struct cgraph_node *node = cgraph_get_node (current_function_decl); |
| struct cgraph_edge *edge; |
| unsigned int todo = 0; |
| int iterations = 0; |
| bool inlined = false; |
| |
| if (seen_error ()) |
| return 0; |
| |
| /* Do nothing if datastructures for ipa-inliner are already computed. This |
| happens when some pass decides to construct new function and |
| cgraph_add_new_function calls lowering passes and early optimization on |
| it. This may confuse ourself when early inliner decide to inline call to |
| function clone, because function clones don't have parameter list in |
| ipa-prop matching their signature. */ |
| if (ipa_node_params_vector) |
| return 0; |
| |
| #ifdef ENABLE_CHECKING |
| verify_cgraph_node (node); |
| #endif |
| |
| /* Even when not optimizing or not inlining inline always-inline |
| functions. */ |
| inlined = inline_always_inline_functions (node); |
| |
| if (!optimize |
| || flag_no_inline |
| || !flag_early_inlining |
| /* Never inline regular functions into always-inline functions |
| during incremental inlining. This sucks as functions calling |
| always inline functions will get less optimized, but at the |
| same time inlining of functions calling always inline |
| function into an always inline function might introduce |
| cycles of edges to be always inlined in the callgraph. |
| |
| We might want to be smarter and just avoid this type of inlining. */ |
| || DECL_DISREGARD_INLINE_LIMITS (node->symbol.decl)) |
| ; |
| else if (lookup_attribute ("flatten", |
| DECL_ATTRIBUTES (node->symbol.decl)) != NULL) |
| { |
| /* When the function is marked to be flattened, recursively inline |
| all calls in it. */ |
| if (dump_file) |
| fprintf (dump_file, |
| "Flattening %s\n", cgraph_node_name (node)); |
| flatten_function (node, true); |
| inlined = true; |
| } |
| else |
| { |
| /* We iterate incremental inlining to get trivial cases of indirect |
| inlining. */ |
| while (iterations < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS) |
| && early_inline_small_functions (node)) |
| { |
| timevar_push (TV_INTEGRATION); |
| todo |= optimize_inline_calls (current_function_decl); |
| |
| /* Technically we ought to recompute inline parameters so the new |
| iteration of early inliner works as expected. We however have |
| values approximately right and thus we only need to update edge |
| info that might be cleared out for newly discovered edges. */ |
| for (edge = node->callees; edge; edge = edge->next_callee) |
| { |
| struct inline_edge_summary *es = inline_edge_summary (edge); |
| es->call_stmt_size |
| = estimate_num_insns (edge->call_stmt, &eni_size_weights); |
| es->call_stmt_time |
| = estimate_num_insns (edge->call_stmt, &eni_time_weights); |
| if (edge->callee->symbol.decl |
| && !gimple_check_call_matching_types (edge->call_stmt, |
| edge->callee->symbol.decl)) |
| edge->call_stmt_cannot_inline_p = true; |
| } |
| timevar_pop (TV_INTEGRATION); |
| iterations++; |
| inlined = false; |
| } |
| if (dump_file) |
| fprintf (dump_file, "Iterations: %i\n", iterations); |
| } |
| |
| if (inlined) |
| { |
| timevar_push (TV_INTEGRATION); |
| todo |= optimize_inline_calls (current_function_decl); |
| timevar_pop (TV_INTEGRATION); |
| } |
| |
| cfun->always_inline_functions_inlined = true; |
| |
| return todo; |
| } |
| |
| struct gimple_opt_pass pass_early_inline = |
| { |
| { |
| GIMPLE_PASS, |
| "einline", /* name */ |
| NULL, /* gate */ |
| early_inliner, /* execute */ |
| NULL, /* sub */ |
| NULL, /* next */ |
| 0, /* static_pass_number */ |
| TV_EARLY_INLINING, /* tv_id */ |
| PROP_ssa, /* properties_required */ |
| 0, /* properties_provided */ |
| 0, /* properties_destroyed */ |
| 0, /* todo_flags_start */ |
| 0 /* todo_flags_finish */ |
| } |
| }; |
| |
| |
| /* When to run IPA inlining. Inlining of always-inline functions |
| happens during early inlining. |
| |
| Enable inlining unconditoinally at -flto. We need size estimates to |
| drive partitioning. */ |
| |
| static bool |
| gate_ipa_inline (void) |
| { |
| return optimize || flag_lto || flag_wpa; |
| } |
| |
| struct ipa_opt_pass_d pass_ipa_inline = |
| { |
| { |
| IPA_PASS, |
| "inline", /* name */ |
| gate_ipa_inline, /* gate */ |
| ipa_inline, /* execute */ |
| NULL, /* sub */ |
| NULL, /* next */ |
| 0, /* static_pass_number */ |
| TV_IPA_INLINING, /* tv_id */ |
| 0, /* properties_required */ |
| 0, /* properties_provided */ |
| 0, /* properties_destroyed */ |
| TODO_remove_functions, /* todo_flags_finish */ |
| TODO_dump_symtab |
| | TODO_remove_functions | TODO_ggc_collect /* todo_flags_finish */ |
| }, |
| inline_generate_summary, /* generate_summary */ |
| inline_write_summary, /* write_summary */ |
| inline_read_summary, /* read_summary */ |
| NULL, /* write_optimization_summary */ |
| NULL, /* read_optimization_summary */ |
| NULL, /* stmt_fixup */ |
| 0, /* TODOs */ |
| inline_transform, /* function_transform */ |
| NULL, /* variable_transform */ |
| }; |