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ipa-inline.c
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ipa-inline.c
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/* Inlining decision heuristics.
Copyright (C) 2003, 2004, 2007, 2008, 2009 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
We separate inlining decisions from the inliner itself and store it
inside callgraph as so called inline plan. Refer to cgraph.c
documentation about particular representation of inline plans in the
callgraph.
There are three major parts of this file:
cgraph_mark_inline implementation
This function allows to mark given call inline and performs necessary
modifications of cgraph (production of the clones and updating overall
statistics)
inlining heuristics limits
These functions allow to check that particular inlining is allowed
by the limits specified by user (allowed function growth, overall unit
growth and so on).
inlining heuristics
This is implementation of IPA pass aiming to get as much of benefit
from inlining obeying the limits checked above.
The implementation of particular heuristics is separated from
the rest of code to make it easier to replace it with more complicated
implementation in the future. The rest of inlining code acts as a
library aimed to modify the callgraph and verify that the parameters
on code size growth fits.
To mark given call inline, use cgraph_mark_inline function, the
verification is performed by cgraph_default_inline_p and
cgraph_check_inline_limits.
The heuristics implements simple knapsack style algorithm ordering
all functions by their "profitability" (estimated by code size growth)
and inlining them in priority order.
cgraph_decide_inlining implements heuristics taking whole callgraph
into account, while cgraph_decide_inlining_incrementally considers
only one function at a time and is used by early inliner.
The inliner itself is split into several passes:
pass_inline_parameters
This pass computes local properties of functions that are used by inliner:
estimated function body size, whether function is inlinable at all and
stack frame consumption.
Before executing any of inliner passes, this local pass has to be applied
to each function in the callgraph (ie run as subpass of some earlier
IPA pass). The results are made out of date by any optimization applied
on the function body.
pass_early_inlining
Simple local inlining pass inlining callees into current function. This
pass makes no global whole compilation unit analysis and this when allowed
to do inlining expanding code size it might result in unbounded growth of
whole unit.
The pass is run during conversion into SSA form. Only functions already
converted into SSA form are inlined, so the conversion must happen in
topological order on the callgraph (that is maintained by pass manager).
The functions after inlining are early optimized so the early inliner sees
unoptimized function itself, but all considered callees are already
optimized allowing it to unfold abstraction penalty on C++ effectively and
cheaply.
pass_ipa_early_inlining
With profiling, the early inlining is also necessary to reduce
instrumentation costs on program with high abstraction penalty (doing
many redundant calls). This can't happen in parallel with early
optimization and profile instrumentation, because we would end up
re-instrumenting already instrumented function bodies we brought in via
inlining.
To avoid this, this pass is executed as IPA pass before profiling. It is
simple wrapper to pass_early_inlining and ensures first inlining.
pass_ipa_inline
This is the main pass implementing simple greedy algorithm to do inlining
of small functions that results in overall growth of compilation unit and
inlining of functions called once. The pass compute just so called inline
plan (representation of inlining to be done in callgraph) and unlike early
inlining it is not performing the inlining itself.
pass_apply_inline
This pass performs actual inlining according to pass_ipa_inline on given
function. Possible the function body before inlining is saved when it is
needed for further inlining later.
*/
#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 "timevar.h"
#include "params.h"
#include "fibheap.h"
#include "intl.h"
#include "tree-pass.h"
#include "hashtab.h"
#include "coverage.h"
#include "ggc.h"
#include "tree-flow.h"
#include "rtl.h"
#include "ipa-prop.h"
/* Mode incremental inliner operate on:
In ALWAYS_INLINE only functions marked
always_inline are inlined. This mode is used after detecting cycle during
flattening.
In SIZE mode, only functions that reduce function body size after inlining
are inlined, this is used during early inlining.
in ALL mode, everything is inlined. This is used during flattening. */
enum inlining_mode {
INLINE_NONE = 0,
INLINE_ALWAYS_INLINE,
INLINE_SIZE,
INLINE_ALL
};
static bool
cgraph_decide_inlining_incrementally (struct cgraph_node *, enum inlining_mode,
int);
/* Statistics we collect about inlining algorithm. */
static int ncalls_inlined;
static int nfunctions_inlined;
static int overall_insns;
static gcov_type max_count;
/* Holders of ipa cgraph hooks: */
static struct cgraph_node_hook_list *function_insertion_hook_holder;
static inline struct inline_summary *
inline_summary (struct cgraph_node *node)
{
return &node->local.inline_summary;
}
/* Estimate size of the function after inlining WHAT into TO. */
static int
cgraph_estimate_size_after_inlining (int times, struct cgraph_node *to,
struct cgraph_node *what)
{
int size;
tree fndecl = what->decl, arg;
int call_insns = PARAM_VALUE (PARAM_INLINE_CALL_COST);
for (arg = DECL_ARGUMENTS (fndecl); arg; arg = TREE_CHAIN (arg))
call_insns += estimate_move_cost (TREE_TYPE (arg));
size = (what->global.insns - call_insns) * times + to->global.insns;
gcc_assert (size >= 0);
return size;
}
/* E is expected to be an edge being inlined. Clone destination node of
the edge and redirect it to the new clone.
DUPLICATE is used for bookkeeping on whether we are actually creating new
clones or re-using node originally representing out-of-line function call.
*/
void
cgraph_clone_inlined_nodes (struct cgraph_edge *e, bool duplicate,
bool update_original)
{
HOST_WIDE_INT peak;
if (duplicate)
{
/* We may eliminate the need for out-of-line copy to be output.
In that case just go ahead and re-use it. */
if (!e->callee->callers->next_caller
&& !e->callee->needed
&& !cgraph_new_nodes)
{
gcc_assert (!e->callee->global.inlined_to);
if (e->callee->analyzed)
overall_insns -= e->callee->global.insns, nfunctions_inlined++;
duplicate = false;
}
else
{
struct cgraph_node *n;
n = cgraph_clone_node (e->callee, e->count, e->frequency, e->loop_nest,
update_original);
cgraph_redirect_edge_callee (e, n);
}
}
if (e->caller->global.inlined_to)
e->callee->global.inlined_to = e->caller->global.inlined_to;
else
e->callee->global.inlined_to = e->caller;
e->callee->global.stack_frame_offset
= e->caller->global.stack_frame_offset
+ inline_summary (e->caller)->estimated_self_stack_size;
peak = e->callee->global.stack_frame_offset
+ inline_summary (e->callee)->estimated_self_stack_size;
if (e->callee->global.inlined_to->global.estimated_stack_size < peak)
e->callee->global.inlined_to->global.estimated_stack_size = peak;
/* Recursively clone all bodies. */
for (e = e->callee->callees; e; e = e->next_callee)
if (!e->inline_failed)
cgraph_clone_inlined_nodes (e, duplicate, update_original);
}
/* Mark edge E as inlined and update callgraph accordingly. UPDATE_ORIGINAL
specify whether profile of original function should be updated. If any new
indirect edges are discovered in the process, add them to NEW_EDGES, unless
it is NULL. Return true iff any new callgraph edges were discovered as a
result of inlining. */
static bool
cgraph_mark_inline_edge (struct cgraph_edge *e, bool update_original,
VEC (cgraph_edge_p, heap) **new_edges)
{
int old_insns = 0, new_insns = 0;
struct cgraph_node *to = NULL, *what;
struct cgraph_edge *curr = e;
if (e->callee->inline_decl)
cgraph_redirect_edge_callee (e, cgraph_node (e->callee->inline_decl));
gcc_assert (e->inline_failed);
e->inline_failed = NULL;
if (!e->callee->global.inlined)
DECL_POSSIBLY_INLINED (e->callee->decl) = true;
e->callee->global.inlined = true;
cgraph_clone_inlined_nodes (e, true, update_original);
what = e->callee;
/* Now update size of caller and all functions caller is inlined into. */
for (;e && !e->inline_failed; e = e->caller->callers)
{
old_insns = e->caller->global.insns;
new_insns = cgraph_estimate_size_after_inlining (1, e->caller,
what);
gcc_assert (new_insns >= 0);
to = e->caller;
to->global.insns = new_insns;
}
gcc_assert (what->global.inlined_to == to);
if (new_insns > old_insns)
overall_insns += new_insns - old_insns;
ncalls_inlined++;
if (flag_indirect_inlining)
return ipa_propagate_indirect_call_infos (curr, new_edges);
else
return false;
}
/* Mark all calls of EDGE->CALLEE inlined into EDGE->CALLER.
Return following unredirected edge in the list of callers
of EDGE->CALLEE */
static struct cgraph_edge *
cgraph_mark_inline (struct cgraph_edge *edge)
{
struct cgraph_node *to = edge->caller;
struct cgraph_node *what = edge->callee;
struct cgraph_edge *e, *next;
gcc_assert (!gimple_call_cannot_inline_p (edge->call_stmt));
/* Look for all calls, mark them inline and clone recursively
all inlined functions. */
for (e = what->callers; e; e = next)
{
next = e->next_caller;
if (e->caller == to && e->inline_failed)
{
cgraph_mark_inline_edge (e, true, NULL);
if (e == edge)
edge = next;
}
}
return edge;
}
/* Estimate the growth caused by inlining NODE into all callees. */
static int
cgraph_estimate_growth (struct cgraph_node *node)
{
int growth = 0;
struct cgraph_edge *e;
bool self_recursive = false;
if (node->global.estimated_growth != INT_MIN)
return node->global.estimated_growth;
for (e = node->callers; e; e = e->next_caller)
{
if (e->caller == node)
self_recursive = true;
if (e->inline_failed)
growth += (cgraph_estimate_size_after_inlining (1, e->caller, node)
- e->caller->global.insns);
}
/* ??? Wrong for non-trivially self recursive functions or cases where
we decide to not inline for different reasons, but it is not big deal
as in that case we will keep the body around, but we will also avoid
some inlining. */
if (!node->needed && !DECL_EXTERNAL (node->decl) && !self_recursive)
growth -= node->global.insns;
node->global.estimated_growth = growth;
return growth;
}
/* Return false when inlining WHAT into TO is not good idea
as it would cause too large growth of function bodies.
When ONE_ONLY is true, assume that only one call site is going
to be inlined, otherwise figure out how many call sites in
TO calls WHAT and verify that all can be inlined.
*/
static bool
cgraph_check_inline_limits (struct cgraph_node *to, struct cgraph_node *what,
const char **reason, bool one_only)
{
int times = 0;
struct cgraph_edge *e;
int newsize;
int limit;
HOST_WIDE_INT stack_size_limit, inlined_stack;
if (one_only)
times = 1;
else
for (e = to->callees; e; e = e->next_callee)
if (e->callee == what)
times++;
if (to->global.inlined_to)
to = to->global.inlined_to;
/* When inlining large function body called once into small function,
take the inlined function as base for limiting the growth. */
if (inline_summary (to)->self_insns > inline_summary(what)->self_insns)
limit = inline_summary (to)->self_insns;
else
limit = inline_summary (what)->self_insns;
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 = cgraph_estimate_size_after_inlining (times, to, what);
if (newsize >= to->global.insns
&& newsize > PARAM_VALUE (PARAM_LARGE_FUNCTION_INSNS)
&& newsize > limit)
{
if (reason)
*reason = N_("--param large-function-growth limit reached");
return false;
}
stack_size_limit = inline_summary (to)->estimated_self_stack_size;
stack_size_limit += stack_size_limit * PARAM_VALUE (PARAM_STACK_FRAME_GROWTH) / 100;
inlined_stack = (to->global.stack_frame_offset
+ inline_summary (to)->estimated_self_stack_size
+ what->global.estimated_stack_size);
if (inlined_stack > stack_size_limit
&& inlined_stack > PARAM_VALUE (PARAM_LARGE_STACK_FRAME))
{
if (reason)
*reason = N_("--param large-stack-frame-growth limit reached");
return false;
}
return true;
}
/* Return true when function N is small enough to be inlined. */
bool
cgraph_default_inline_p (struct cgraph_node *n, const char **reason)
{
tree decl = n->decl;
if (n->inline_decl)
decl = n->inline_decl;
if (!flag_inline_small_functions && !DECL_DECLARED_INLINE_P (decl))
{
if (reason)
*reason = N_("function not inline candidate");
return false;
}
if (!DECL_STRUCT_FUNCTION (decl)->cfg)
{
if (reason)
*reason = N_("function body not available");
return false;
}
if (DECL_DECLARED_INLINE_P (decl))
{
if (n->global.insns >= MAX_INLINE_INSNS_SINGLE)
{
if (reason)
*reason = N_("--param max-inline-insns-single limit reached");
return false;
}
}
else
{
if (n->global.insns >= MAX_INLINE_INSNS_AUTO)
{
if (reason)
*reason = N_("--param max-inline-insns-auto limit reached");
return false;
}
}
return true;
}
/* Return true when inlining WHAT would create recursive inlining.
We call recursive inlining all cases where same function appears more than
once in the single recursion nest path in the inline graph. */
static bool
cgraph_recursive_inlining_p (struct cgraph_node *to,
struct cgraph_node *what,
const char **reason)
{
bool recursive;
if (to->global.inlined_to)
recursive = what->decl == to->global.inlined_to->decl;
else
recursive = what->decl == to->decl;
/* Marking recursive function inline has sane semantic and thus we should
not warn on it. */
if (recursive && reason)
*reason = (what->local.disregard_inline_limits
? N_("recursive inlining") : "");
return recursive;
}
/* 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
cgraph_edge_badness (struct cgraph_edge *edge)
{
int badness;
int growth =
cgraph_estimate_size_after_inlining (1, edge->caller, edge->callee);
growth -= edge->caller->global.insns;
/* Always prefer inlining saving code size. */
if (growth <= 0)
badness = INT_MIN - growth;
/* When profiling is available, base priorities -(#calls / growth).
So we optimize for overall number of "executed" inlined calls. */
else if (max_count)
badness = ((int)((double)edge->count * INT_MIN / max_count)) / growth;
/* 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.
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). */
else if (flag_guess_branch_prob)
{
int div = edge->frequency * 100 / CGRAPH_FREQ_BASE;
int growth =
cgraph_estimate_size_after_inlining (1, edge->caller, edge->callee);
growth -= edge->caller->global.insns;
badness = growth * 256;
/* Decrease badness if call is nested. */
/* Compress the range so we don't overflow. */
if (div > 256)
div = 256 + ceil_log2 (div) - 8;
if (div < 1)
div = 1;
if (badness > 0)
badness /= div;
badness += cgraph_estimate_growth (edge->callee);
}
/* 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 (edge->loop_nest, 8);
badness = cgraph_estimate_growth (edge->callee) * 256;
/* Decrease badness if call is nested. */
if (badness > 0)
badness >>= nest;
else
{
badness <<= nest;
}
}
/* Make recursive inlining happen always after other inlining is done. */
if (cgraph_recursive_inlining_p (edge->caller, edge->callee, NULL))
return badness + 1;
else
return badness;
}
/* Recompute heap nodes for each of caller edge. */
static void
update_caller_keys (fibheap_t heap, struct cgraph_node *node,
bitmap updated_nodes)
{
struct cgraph_edge *edge;
const char *failed_reason;
if (!node->local.inlinable || node->local.disregard_inline_limits
|| node->global.inlined_to)
return;
if (bitmap_bit_p (updated_nodes, node->uid))
return;
bitmap_set_bit (updated_nodes, node->uid);
node->global.estimated_growth = INT_MIN;
if (!node->local.inlinable)
return;
/* Prune out edges we won't inline into anymore. */
if (!cgraph_default_inline_p (node, &failed_reason))
{
for (edge = node->callers; edge; edge = edge->next_caller)
if (edge->aux)
{
fibheap_delete_node (heap, (fibnode_t) edge->aux);
edge->aux = NULL;
if (edge->inline_failed)
edge->inline_failed = failed_reason;
}
return;
}
for (edge = node->callers; edge; edge = edge->next_caller)
if (edge->inline_failed)
{
int badness = cgraph_edge_badness (edge);
if (edge->aux)
{
fibnode_t n = (fibnode_t) edge->aux;
gcc_assert (n->data == edge);
if (n->key == badness)
continue;
/* fibheap_replace_key only increase the keys. */
if (fibheap_replace_key (heap, n, badness))
continue;
fibheap_delete_node (heap, (fibnode_t) edge->aux);
}
edge->aux = fibheap_insert (heap, badness, edge);
}
}
/* Recompute heap nodes for each of caller edges of each of callees. */
static void
update_callee_keys (fibheap_t heap, struct cgraph_node *node,
bitmap updated_nodes)
{
struct cgraph_edge *e;
node->global.estimated_growth = INT_MIN;
for (e = node->callees; e; e = e->next_callee)
if (e->inline_failed)
update_caller_keys (heap, e->callee, updated_nodes);
else if (!e->inline_failed)
update_callee_keys (heap, e->callee, updated_nodes);
}
/* 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)
{
static int priority;
struct cgraph_edge *e;
for (e = where->callees; e; e = e->next_callee)
if (e->callee == node)
{
/* When profile feedback is available, prioritize by expected number
of calls. Without profile feedback we maintain simple queue
to order candidates via recursive depths. */
fibheap_insert (heap,
!max_count ? priority++
: -(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
cgraph_decide_recursive_inlining (struct cgraph_node *node,
VEC (cgraph_edge_p, heap) **new_edges)
{
int limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO);
int max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO);
int probability = PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY);
fibheap_t heap;
struct cgraph_edge *e;
struct cgraph_node *master_clone, *next;
int depth = 0;
int n = 0;
if (optimize_function_for_size_p (DECL_STRUCT_FUNCTION (node->decl))
|| (!flag_inline_functions && !DECL_DECLARED_INLINE_P (node->decl)))
return false;
if (DECL_DECLARED_INLINE_P (node->decl))
{
limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE);
max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH);
}
/* Make sure that function is small enough to be considered for inlining. */
if (!max_depth
|| cgraph_estimate_size_after_inlining (1, node, node) >= 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));
/* We need original clone to copy around. */
master_clone = cgraph_clone_node (node, node->count, CGRAPH_FREQ_BASE, 1, false);
master_clone->needed = true;
for (e = master_clone->callees; e; e = e->next_callee)
if (!e->inline_failed)
cgraph_clone_inlined_nodes (e, true, false);
/* Do the inlining and update list of recursive call during process. */
while (!fibheap_empty (heap)
&& (cgraph_estimate_size_after_inlining (1, node, master_clone)
<= limit))
{
struct cgraph_edge *curr
= (struct cgraph_edge *) fibheap_extract_min (heap);
struct cgraph_node *cnode;
depth = 1;
for (cnode = curr->caller;
cnode->global.inlined_to; cnode = cnode->callers->caller)
if (node->decl == curr->callee->decl)
depth++;
if (depth > max_depth)
{
if (dump_file)
fprintf (dump_file,
" maximal depth reached\n");
continue;
}
if (max_count)
{
if (!cgraph_maybe_hot_edge_p (curr))
{
if (dump_file)
fprintf (dump_file, " Not inlining cold call\n");
continue;
}
if (curr->count * 100 / node->count < probability)
{
if (dump_file)
fprintf (dump_file,
" Probability of edge is too small\n");
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");
}
cgraph_redirect_edge_callee (curr, master_clone);
cgraph_mark_inline_edge (curr, false, new_edges);
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 (dump_file)
fprintf (dump_file,
"\n Inlined %i times, body grown from %i to %i insns\n", n,
master_clone->global.insns, node->global.insns);
/* 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_nodes; node != master_clone;
node = next)
{
next = node->next;
if (node->global.inlined_to == master_clone)
cgraph_remove_node (node);
}
cgraph_remove_node (master_clone);
/* FIXME: Recursive inlining actually reduces number of calls of the
function. At this place we should probably walk the function and
inline clones and compensate the counts accordingly. This probably
doesn't matter much in practice. */
return n > 0;
}
/* Set inline_failed for all callers of given function to REASON. */
static void
cgraph_set_inline_failed (struct cgraph_node *node, const char *reason)
{
struct cgraph_edge *e;
if (dump_file)
fprintf (dump_file, "Inlining failed: %s\n", reason);
for (e = node->callers; e; e = e->next_caller)
if (e->inline_failed)
e->inline_failed = reason;
}
/* 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);
edge->aux = fibheap_insert (heap, cgraph_edge_badness (edge), edge);
}
}
/* We use greedy algorithm for inlining of small functions:
All inline candidates are put into prioritized heap based on estimated
growth of the overall number of instructions and then update the estimates.
INLINED and INLINED_CALEES are just pointers to arrays large enough
to be passed to cgraph_inlined_into and cgraph_inlined_callees. */
static void
cgraph_decide_inlining_of_small_functions (void)
{
struct cgraph_node *node;
struct cgraph_edge *edge;
const char *failed_reason;
fibheap_t heap = fibheap_new ();
bitmap updated_nodes = BITMAP_ALLOC (NULL);
int min_insns, max_insns;
VEC (cgraph_edge_p, heap) *new_indirect_edges = NULL;
if (flag_indirect_inlining)
new_indirect_edges = VEC_alloc (cgraph_edge_p, heap, 8);
if (dump_file)
fprintf (dump_file, "\nDeciding on smaller functions:\n");
/* Put all inline candidates into the heap. */
for (node = cgraph_nodes; node; node = node->next)
{
if (!node->local.inlinable || !node->callers
|| node->local.disregard_inline_limits)
continue;
if (dump_file)
fprintf (dump_file, "Considering inline candidate %s.\n", cgraph_node_name (node));
node->global.estimated_growth = INT_MIN;
if (!cgraph_default_inline_p (node, &failed_reason))
{
cgraph_set_inline_failed (node, failed_reason);
continue;
}
for (edge = node->callers; edge; edge = edge->next_caller)
if (edge->inline_failed)
{
gcc_assert (!edge->aux);
edge->aux = fibheap_insert (heap, cgraph_edge_badness (edge), edge);
}
}
max_insns = compute_max_insns (overall_insns);
min_insns = overall_insns;
while (overall_insns <= max_insns
&& (edge = (struct cgraph_edge *) fibheap_extract_min (heap)))
{
int old_insns = overall_insns;
struct cgraph_node *where;
int growth =
cgraph_estimate_size_after_inlining (1, edge->caller, edge->callee);
const char *not_good = NULL;
growth -= edge->caller->global.insns;
if (dump_file)
{
fprintf (dump_file,
"\nConsidering %s with %i insns\n",
cgraph_node_name (edge->callee),
edge->callee->global.insns);
fprintf (dump_file,
" to be inlined into %s\n"
" Estimated growth after inlined into all callees is %+i insns.\n"
" Estimated badness is %i, frequency %.2f.\n",
cgraph_node_name (edge->caller),
cgraph_estimate_growth (edge->callee),
cgraph_edge_badness (edge),
edge->frequency / (double)CGRAPH_FREQ_BASE);
if (edge->count)
fprintf (dump_file," Called "HOST_WIDEST_INT_PRINT_DEC"x\n", edge->count);
}
gcc_assert (edge->aux);
edge->aux = NULL;
if (!edge->inline_failed)
continue;
/* When not having profile info ready we don't weight by any way the
position of call in procedure itself. This means if call of
function A from function B seems profitable to inline, the recursive
call of function A in inline copy of A in B will look profitable too
and we end up inlining until reaching maximal function growth. This
is not good idea so prohibit the recursive inlining.
??? When the frequencies are taken into account we might not need this
restriction.
We need to be cureful here, in some testcases, e.g. directivec.c in
libcpp, we can estimate self recursive function to have negative growth
for inlining completely.
*/
if (!edge->count)
{
where = edge->caller;
while (where->global.inlined_to)
{
if (where->decl == edge->callee->decl)
break;
where = where->callers->caller;
}
if (where->global.inlined_to)
{
edge->inline_failed
= (edge->callee->local.disregard_inline_limits ? N_("recursive inlining") : "");
if (dump_file)
fprintf (dump_file, " inline_failed:Recursive inlining performed only for function itself.\n");
continue;
}
}
if (!cgraph_maybe_hot_edge_p (edge))
not_good = N_("call is unlikely and code size would grow");
if (!flag_inline_functions
&& !DECL_DECLARED_INLINE_P (edge->callee->decl))
not_good = N_("function not declared inline and code size would grow");
if (optimize_function_for_size_p (DECL_STRUCT_FUNCTION(edge->caller->decl)))
not_good = N_("optimizing for size and code size would grow");
if (not_good && growth > 0 && cgraph_estimate_growth (edge->callee) > 0)
{
if (!cgraph_recursive_inlining_p (edge->caller, edge->callee,
&edge->inline_failed))
{
edge->inline_failed = not_good;
if (dump_file)
fprintf (dump_file, " inline_failed:%s.\n", edge->inline_failed);
}
continue;
}
if (!cgraph_default_inline_p (edge->callee, &edge->inline_failed))
{
if (!cgraph_recursive_inlining_p (edge->caller, edge->callee,
&edge->inline_failed))
{
if (dump_file)
fprintf (dump_file, " inline_failed:%s.\n", edge->inline_failed);
}
continue;
}
if (!tree_can_inline_p (edge->caller->decl, edge->callee->decl))
{
gimple_call_set_cannot_inline (edge->call_stmt, true);
edge->inline_failed = N_("target specific option mismatch");
if (dump_file)
fprintf (dump_file, " inline_failed:%s.\n", edge->inline_failed);
continue;
}
if (cgraph_recursive_inlining_p (edge->caller, edge->callee,
&edge->inline_failed))
{
where = edge->caller;
if (where->global.inlined_to)
where = where->global.inlined_to;
if (!cgraph_decide_recursive_inlining (where,
flag_indirect_inlining
? &new_indirect_edges : NULL))
continue;
if (flag_indirect_inlining)
add_new_edges_to_heap (heap, new_indirect_edges);
update_callee_keys (heap, where, updated_nodes);
}
else
{