From: Jan Hubicka <jh@suse.cz>
Date: Thu, 27 Jul 2006 16:03:22 +0000 (+0200)
Subject: re PR middle-end/28071 (A file that can not be compiled in reasonable time/space)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=96d0cc8186a650f653ec0bb47168b3ccb6426ce2;p=gcc.git

re PR middle-end/28071 (A file that can not be compiled in reasonable time/space)

	PR rtl-optimization/28071
	* cselib.c (cselib_process_insn): Don't remove useless values too
	often for very large hashtables.

From-SVN: r115777
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4ebe39ffb02..c5c0d6ff5a5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2006-07-27  Jan Hubicka  <jh@suse.cz>
+
+	PR rtl-optimization/28071
+	* cselib.c (cselib_process_insn): Don't remove useless values too
+	often for very large hashtables.
+
 2006-07-27  Jan Hubicka  <jh@suse.cz>
 
 	PR rtl-optimization/28071
diff --git a/gcc/cselib.c b/gcc/cselib.c
index 0fc8aeef2cf..edfc328c0d8 100644
--- a/gcc/cselib.c
+++ b/gcc/cselib.c
@@ -1437,7 +1437,11 @@ cselib_process_insn (rtx insn)
     cselib_current_insn_in_libcall = false;
   cselib_current_insn = 0;
 
-  if (n_useless_values > MAX_USELESS_VALUES)
+  if (n_useless_values > MAX_USELESS_VALUES
+      /* remove_useless_values is linear in the hash table size.  Avoid
+         quadratic behaviour for very large hashtables with very few
+	 useless elements.  */
+      && (unsigned int)n_useless_values > cselib_hash_table->n_elements / 4)
     remove_useless_values ();
 }