From: Jan Hubicka <jh@suse.cz>
Date: Thu, 21 Nov 2019 08:15:47 +0000 (+0100)
Subject: Avoid quadratic behaviour of early inliner.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=49e26500723ff8d18ebec8057d1e686ad91113f9;p=gcc.git

Avoid quadratic behaviour of early inliner.

	* ipa-inline.c (want_early_inline_function_p): Do not estimate
	edge growth when callee function is very large.
	* ipa-inline.h (estimate_min_edge_growth): New.

From-SVN: r278542
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index cab81d5e910..904b54c9ebe 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-11-20  Jan Hubicka  <jh@suse.cz>
+
+	* ipa-inline.c (want_early_inline_function_p): Do not estimate
+	edge growth when callee function is very large.
+	* ipa-inline.h (estimate_min_edge_growth): New.
+
 2019-11-20  Jan Hubicka  <jh@suse.cz>
 
 	* ipa-fnsummary.c (ipa_fn_summary::account_size_time): Allow
diff --git a/gcc/ipa-inline.c b/gcc/ipa-inline.c
index 5d8b87a7bc3..6da3e96b45d 100644
--- a/gcc/ipa-inline.c
+++ b/gcc/ipa-inline.c
@@ -672,14 +672,29 @@ want_early_inline_function_p (struct cgraph_edge *e)
     }
   else
     {
-      int growth = estimate_edge_growth (e);
+      /* First take care of very large functions.  */
+      int min_growth = estimate_min_edge_growth (e), growth = 0;
       int n;
       int early_inlining_insns = opt_for_fn (e->caller->decl, optimize) >= 3
 				 ? param_early_inlining_insns
 				 : param_early_inlining_insns_o2;
 
+      if (min_growth > early_inlining_insns)
+	{
+	  if (dump_enabled_p ())
+	    dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
+			     "  will not early inline: %C->%C, "
+			     "call is cold and code would grow "
+			     "at least by %i\n",
+			     e->caller, callee,
+			     min_growth);
+	  want_inline = false;
+	}
+      else
+        growth = estimate_edge_growth (e);
 
-      if (growth <= param_max_inline_insns_size)
+
+      if (!want_inline || growth <= param_max_inline_insns_size)
 	;
       else if (!e->maybe_hot_p ())
 	{
diff --git a/gcc/ipa-inline.h b/gcc/ipa-inline.h
index 626f264d5d0..6273f0747f9 100644
--- a/gcc/ipa-inline.h
+++ b/gcc/ipa-inline.h
@@ -79,6 +79,16 @@ estimate_edge_size (struct cgraph_edge *edge)
   return entry->size - (entry->size > 0);
 }
 
+/* Return lower bound on estimated callee growth after inlining EDGE.  */
+
+static inline int
+estimate_min_edge_growth (struct cgraph_edge *edge)
+{
+  ipa_call_summary *s = ipa_call_summaries->get (edge);
+  struct cgraph_node *callee = edge->callee->ultimate_alias_target ();
+  return (ipa_fn_summaries->get (callee)->min_size - s->call_stmt_size);
+}
+
 /* Return estimated callee growth after inlining EDGE.  */
 
 static inline int