Hi,
in 4.6 timeframe I limited early inlier growth to apply only for leaf functions.
This does not work really well, because with less propagation of address
expressions
we are really not 100% succesfull on detecting C++ forwarders and predicting
them
zero cost. This patch simply makes the cost to be divided by number of
callees, similarly
as in LLVM.
Bootstrapped/regtested x86_64-linux, benchmarked and comitted.
The patch seems consistent win in all benchmarks, most noticeably in tramp3d.
* ipa-inline.c (leaf_node_p): Rename to ...
(num_calls) ... this one.
(want_early_inline_function_p): Allow smal growth on non-leafs.
Index: ipa-inline.c
===================================================================
--- ipa-inline.c (revision 193134)
+++ ipa-inline.c (working copy)
@@ -380,17 +380,18 @@ can_early_inline_edge_p (struct cgraph_e
}
-/* Return true when N is leaf function. Accept cheap builtins
- in leaf functions. */
+/* Return number of calls in N. Ignore cheap builtins. */
-static bool
-leaf_node_p (struct cgraph_node *n)
+static int
+num_calls (struct cgraph_node *n)
{
struct cgraph_edge *e;
+ int num = 0;
+
for (e = n->callees; e; e = e->next_callee)
if (!is_inexpensive_builtin (e->callee->symbol.decl))
- return false;
- return true;
+ num++;
+ return num;
}
@@ -414,6 +415,8 @@ want_early_inline_function_p (struct cgr
else
{
int growth = estimate_edge_growth (e);
+ int n;
+
if (growth <= 0)
;
else if (!cgraph_maybe_hot_edge_p (e)
@@ -427,22 +430,23 @@ want_early_inline_function_p (struct cgr
growth);
want_inline = false;
}
- else if (!leaf_node_p (callee)
- && growth > 0)
+ else if (growth > PARAM_VALUE (PARAM_EARLY_INLINING_INSNS))
{
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",
+ "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;
}
- else if (growth > PARAM_VALUE (PARAM_EARLY_INLINING_INSNS))
+ else if ((n = num_calls (callee)) != 0
+ && growth * (n + 1) > 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",
+ "growth %i exceeds --param early-inlining-insns "
+ "divided by number of calls\n",
xstrdup (cgraph_node_name (e->caller)), e->caller->uid,
xstrdup (cgraph_node_name (callee)), callee->uid,
growth);
