cgraph_mark_inline implementation
- This function allow to mark given call inline and performs neccesary
+ This function allows to mark given call inline and performs necessary
modifications of cgraph (production of the clones and updating overall
statistics)
#include "fibheap.h"
#include "intl.h"
#include "tree-pass.h"
+#include "coverage.h"
/* Statistics we collect about inlining algorithm. */
static int ncalls_inlined;
static int nfunctions_inlined;
static int initial_insns;
static int overall_insns;
+static int max_insns;
+static gcov_type max_count;
/* Estimate size of the function after inlining WHAT into TO. */
cgraph_estimate_size_after_inlining (int times, struct cgraph_node *to,
struct cgraph_node *what)
{
- tree fndecl = what->decl;
- tree arg;
+ 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));
- return (what->global.insns - call_insns) * times + to->global.insns;
+ 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
}
else if (duplicate)
{
- n = cgraph_clone_node (e->callee);
+ n = cgraph_clone_node (e->callee, e->count, e->loop_nest);
cgraph_redirect_edge_callee (e, n);
}
{
int growth = 0;
struct cgraph_edge *e;
+ if (node->global.estimated_growth != INT_MIN)
+ return node->global.estimated_growth;
for (e = node->callers; e; e = e->next_caller)
if (e->inline_failed)
if (!node->needed && !DECL_EXTERNAL (node->decl))
growth -= node->global.insns;
+ node->global.estimated_growth = growth;
return growth;
}
return recursive;
}
-/* Recompute heap nodes for each of callees. */
+/* Return true if the call can be hot. */
+static bool
+cgraph_maybe_hot_edge_p (struct cgraph_edge *edge)
+{
+ if (profile_info && flag_branch_probabilities
+ && (edge->count
+ <= profile_info->sum_max / PARAM_VALUE (HOT_BB_COUNT_FRACTION)))
+ return false;
+ return true;
+}
+
+/* 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.
+
+ For the moment we use estimated growth caused by inlining callee into all
+ it's callers for driving the inlining but once we have loop depth or
+ frequency information readily available we should do better.
+
+ With profiling we use number of executions of each edge to drive the cost.
+ We also should distinguish hot and cold calls where the cold calls are
+ inlined into only when code size is overall improved.
+
+ Value INT_MAX can be returned to prevent function from being inlined.
+ */
+
+static int
+cgraph_edge_badness (struct cgraph_edge *edge)
+{
+ if (max_count)
+ {
+ 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)
+ return INT_MIN - growth;
+ return ((int)((double)edge->count * INT_MIN / max_count)) / growth;
+ }
+ else
+ {
+ int nest = MIN (edge->loop_nest, 8);
+ int badness = cgraph_estimate_growth (edge->callee) * 256;
+
+ 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;
+
+ 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);
+
+ 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 = 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, 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 fibnode **heap_node,
- struct cgraph_node *node)
+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 && heap_node[e->callee->uid])
- fibheap_replace_key (heap, heap_node[e->callee->uid],
- cgraph_estimate_growth (e->callee));
+ if (e->inline_failed)
+ update_caller_keys (heap, e->callee, updated_nodes);
else if (!e->inline_failed)
- update_callee_keys (heap, heap_node, e->callee);
+ update_callee_keys (heap, e->callee, updated_nodes);
}
-/* Enqueue all recursive calls from NODE into queue linked via aux pointers
- in between FIRST and LAST. WHERE is used for bookkeeping while looking
- int calls inlined within NODE. */
+/* 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,
- struct cgraph_edge **first, struct cgraph_edge **last)
+ fibheap_t heap)
{
+ static int priority;
struct cgraph_edge *e;
for (e = where->callees; e; e = e->next_callee)
if (e->callee == node)
{
- if (!*first)
- *first = e;
- else
- (*last)->aux = e;
- *last = e;
+ /* FIXME: Once counts and frequencies are available we should drive the
+ order by these. For now force the order to be simple queue since
+ we get order dependent on recursion depth for free by this. */
+ fibheap_insert (heap, priority++, e);
}
for (e = where->callees; e; e = e->next_callee)
if (!e->inline_failed)
- lookup_recursive_calls (node, e->callee, first, last);
+ 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. */
-static void
+
+static bool
cgraph_decide_recursive_inlining (struct cgraph_node *node)
{
int limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO);
int max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO);
- struct cgraph_edge *first_call = NULL, *last_call = NULL;
- struct cgraph_edge *last_in_current_depth;
+ fibheap_t heap;
struct cgraph_edge *e;
struct cgraph_node *master_clone;
int depth = 0;
/* 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;
- lookup_recursive_calls (node, node, &first_call, &last_call);
- if (!first_call)
- return;
+ 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,
- "\nPerforming recursive inlining on %s\n",
+ " Performing recursive inlining on %s\n",
cgraph_node_name (node));
/* We need original clone to copy around. */
- master_clone = cgraph_clone_node (node);
+ master_clone = cgraph_clone_node (node, 0, 1);
master_clone->needed = true;
for (e = master_clone->callees; e; e = e->next_callee)
if (!e->inline_failed)
cgraph_clone_inlined_nodes (e, true);
/* Do the inlining and update list of recursive call during process. */
- last_in_current_depth = last_call;
- while (first_call
+ while (!fibheap_empty (heap)
&& cgraph_estimate_size_after_inlining (1, node, master_clone) <= limit)
{
- struct cgraph_edge *curr = first_call;
-
- first_call = first_call->aux;
- curr->aux = NULL;
+ struct cgraph_edge *curr = fibheap_extract_min (heap);
+ struct cgraph_node *node;
+
+ depth = 0;
+ for (node = curr->caller;
+ node; node = node->global.inlined_to)
+ if (node->decl == curr->callee->decl)
+ depth++;
+ if (depth > max_depth)
+ continue;
+ if (dump_file)
+ fprintf (dump_file,
+ " Inlining call of depth %i\n", depth);
cgraph_redirect_edge_callee (curr, master_clone);
cgraph_mark_inline_edge (curr);
- lookup_recursive_calls (node, curr->callee, &first_call, &last_call);
-
- if (last_in_current_depth
- && ++depth >= max_depth)
- break;
+ lookup_recursive_calls (node, curr->callee, heap);
n++;
}
- /* Cleanup queue pointers. */
- while (first_call)
- {
- struct cgraph_edge *next = first_call->aux;
- first_call->aux = NULL;
- first_call = next;
- }
+ fibheap_delete (heap);
if (dump_file)
fprintf (dump_file,
"\n Inlined %i times, body grown from %i to %i insns\n", n,
if (node->global.inlined_to == master_clone)
cgraph_remove_node (node);
cgraph_remove_node (master_clone);
+ return true;
}
/* Set inline_failed for all callers of given function to REASON. */
cgraph_decide_inlining_of_small_functions (void)
{
struct cgraph_node *node;
+ struct cgraph_edge *edge;
fibheap_t heap = fibheap_new ();
- struct fibnode **heap_node =
- xcalloc (cgraph_max_uid, sizeof (struct fibnode *));
- int max_insns = ((HOST_WIDEST_INT) initial_insns
- * (100 + PARAM_VALUE (PARAM_INLINE_UNIT_GROWTH)) / 100);
+ bitmap updated_nodes = BITMAP_ALLOC (NULL);
+
+ if (dump_file)
+ fprintf (dump_file, "\nDeciding on smaller functions:\n");
/* Put all inline candidates into the heap. */
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))
{
cgraph_set_inline_failed (node,
N_("--param max-inline-insns-single limit reached"));
continue;
}
- heap_node[node->uid] =
- fibheap_insert (heap, cgraph_estimate_growth (node), node);
- }
- if (dump_file)
- fprintf (dump_file, "\nDeciding on smaller functions:\n");
- while (overall_insns <= max_insns && (node = fibheap_extract_min (heap)))
+ 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);
+ }
+ }
+ while (overall_insns <= max_insns && (edge = fibheap_extract_min (heap)))
{
- struct cgraph_edge *e, *next;
int old_insns = overall_insns;
+ struct cgraph_node *where;
+ int growth =
+ cgraph_estimate_size_after_inlining (1, edge->caller, edge->callee);
+
+ growth -= edge->caller->global.insns;
- heap_node[node->uid] = NULL;
if (dump_file)
- fprintf (dump_file,
- "\nConsidering %s with %i insns\n"
- " Estimated growth is %+i insns.\n",
- cgraph_node_name (node), node->global.insns,
- cgraph_estimate_growth (node));
- if (!cgraph_default_inline_p (node))
{
- cgraph_set_inline_failed (node,
- N_("--param max-inline-insns-single limit reached after inlining into the callee"));
- continue;
+ fprintf (dump_file,
+ "\nConsidering %s with %i insns to be inlined into %s\n"
+ " Estimated growth after inlined into all callees is %+i insns.\n"
+ " Estimated badness is %i.\n",
+ cgraph_node_name (edge->callee),
+ edge->callee->global.insns,
+ cgraph_node_name (edge->caller),
+ cgraph_estimate_growth (edge->callee),
+ cgraph_edge_badness (edge));
+ if (edge->count)
+ fprintf (dump_file," Called "HOST_WIDEST_INT_PRINT_DEC"x\n", edge->count);
}
- for (e = node->callers; e; e = next)
- {
- next = e->next_caller;
- if (e->inline_failed)
- {
- struct cgraph_node *where;
-
- if (cgraph_recursive_inlining_p (e->caller, e->callee,
- &e->inline_failed)
- || !cgraph_check_inline_limits (e->caller, e->callee,
- &e->inline_failed))
- {
- if (dump_file)
- fprintf (dump_file, " Not inlining into %s:%s.\n",
- cgraph_node_name (e->caller), e->inline_failed);
- continue;
- }
- next = cgraph_mark_inline (e);
- where = e->caller;
- if (where->global.inlined_to)
- where = where->global.inlined_to;
+ gcc_assert (edge->aux);
+ edge->aux = NULL;
+ if (!edge->inline_failed)
+ continue;
- if (heap_node[where->uid])
- fibheap_replace_key (heap, heap_node[where->uid],
- cgraph_estimate_growth (where));
+ /* 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. */
+ if (!max_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,
- " Inlined into %s which now has %i insns.\n",
- cgraph_node_name (e->caller),
- e->caller->global.insns);
+ fprintf (dump_file, " inline_failed:Recursive inlining performed only for function itself.\n");
+ continue;
}
}
- cgraph_decide_recursive_inlining (node);
-
- /* Similarly all functions called by the function we just inlined
- are now called more times; update keys. */
- update_callee_keys (heap, heap_node, node);
+ if (!cgraph_maybe_hot_edge_p (edge) && growth > 0)
+ {
+ if (!cgraph_recursive_inlining_p (edge->caller, edge->callee,
+ &edge->inline_failed))
+ {
+ edge->inline_failed =
+ N_("call is unlikely");
+ if (dump_file)
+ fprintf (dump_file, " inline_failed:%s.\n", edge->inline_failed);
+ }
+ continue;
+ }
+ if (!cgraph_default_inline_p (edge->callee))
+ {
+ if (!cgraph_recursive_inlining_p (edge->caller, edge->callee,
+ &edge->inline_failed))
+ {
+ edge->inline_failed =
+ N_("--param max-inline-insns-single limit reached after inlining into the callee");
+ 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))
+ continue;
+ update_callee_keys (heap, where, updated_nodes);
+ }
+ else
+ {
+ if (!cgraph_check_inline_limits (edge->caller, edge->callee,
+ &edge->inline_failed))
+ {
+ if (dump_file)
+ fprintf (dump_file, " Not inlining into %s:%s.\n",
+ cgraph_node_name (edge->caller), edge->inline_failed);
+ continue;
+ }
+ cgraph_mark_inline_edge (edge);
+ update_callee_keys (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 (heap, where, updated_nodes);
+ bitmap_clear (updated_nodes);
if (dump_file)
fprintf (dump_file,
+ " Inlined into %s which now has %i insns.\n",
+ cgraph_node_name (edge->caller),
+ edge->caller->global.insns);
+ if (dump_file)
+ fprintf (dump_file,
" Inlined for a net change of %+i insns.\n",
overall_insns - old_insns);
}
- while ((node = fibheap_extract_min (heap)) != NULL)
- if (!node->local.disregard_inline_limits)
- cgraph_set_inline_failed (node, N_("--param inline-unit-growth limit reached"));
+ while ((edge = fibheap_extract_min (heap)) != NULL)
+ {
+ gcc_assert (edge->aux);
+ edge->aux = NULL;
+ if (!edge->callee->local.disregard_inline_limits && edge->inline_failed
+ && !cgraph_recursive_inlining_p (edge->caller, edge->callee,
+ &edge->inline_failed))
+ edge->inline_failed = N_("--param inline-unit-growth limit reached");
+ }
fibheap_delete (heap);
- free (heap_node);
+ BITMAP_FREE (updated_nodes);
}
/* Decide on the inlining. We do so in the topological order to avoid
int old_insns = 0;
int i;
+ timevar_push (TV_INLINE_HEURISTICS);
+ max_count = 0;
for (node = cgraph_nodes; node; node = node->next)
- initial_insns += node->local.self_insns;
+ {
+ struct cgraph_edge *e;
+ initial_insns += node->local.self_insns;
+ for (e = node->callees; e; e = e->next_callee)
+ if (max_count < e->count)
+ max_count = e->count;
+ }
overall_insns = initial_insns;
+ gcc_assert (!max_count || (profile_info && flag_branch_probabilities));
+
+ max_insns = ((HOST_WIDEST_INT) overall_insns
+ * (100 + PARAM_VALUE (PARAM_INLINE_UNIT_GROWTH)) / 100);
nnodes = cgraph_postorder (order);
}
}
- /* We will never output extern functions we didn't inline.
- ??? Perhaps we can prevent accounting of growth of external
- inline functions. */
- cgraph_remove_unreachable_nodes (false, dump_file);
-
if (dump_file)
fprintf (dump_file,
"\nInlined %i calls, eliminated %i functions, "
ncalls_inlined, nfunctions_inlined, initial_insns,
overall_insns);
free (order);
+ timevar_pop (TV_INLINE_HEURISTICS);
}
/* Decide on the inlining. We do so in the topological order to avoid
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