From: Jakub Jelinek <jakub@redhat.com>
Date: Thu, 7 Apr 2011 18:28:29 +0000 (+0200)
Subject: backport: re PR rtl-optimization/48141 (DSE compile time hog)
X-Git-Tag: releases/gcc-4.5.3~91
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ac75cc393a60832fa56df7cbcb239133c2f67f27;p=thirdparty%2Fgcc.git

backport: re PR rtl-optimization/48141 (DSE compile time hog)

	Backported from mainline
	2011-03-17  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/48141
	* dse.c (record_store): If no positions are needed in an insn
	that cannot be deleted, at least unchain it from active_local_stores.

	* gcc.dg/pr48141.c: New test.

From-SVN: r172116
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5fe612b12971..01ce6860d7d7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,12 @@
 2011-04-07  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2011-03-17  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/48141
+	* dse.c (record_store): If no positions are needed in an insn
+	that cannot be deleted, at least unchain it from active_local_stores.
+
 	2011-03-03  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/47963
diff --git a/gcc/dse.c b/gcc/dse.c
index 2be8a942c75f..4f7a0683b9c5 100644
--- a/gcc/dse.c
+++ b/gcc/dse.c
@@ -1592,8 +1592,7 @@ record_store (rtx body, bb_info_t bb_info)
 
       /* An insn can be deleted if every position of every one of
 	 its s_infos is zero.  */
-      if (any_positions_needed_p (s_info)
-	  || ptr->cannot_delete)
+      if (any_positions_needed_p (s_info))
 	del = false;
 
       if (del)
@@ -1605,7 +1604,8 @@ record_store (rtx body, bb_info_t bb_info)
 	  else
 	    active_local_stores = ptr->next_local_store;
 
-	  delete_dead_store_insn (insn_to_delete);
+	  if (!insn_to_delete->cannot_delete)
+	    delete_dead_store_insn (insn_to_delete);
 	}
       else
 	last = ptr;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a924b4356b3e..175a4548ac81 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2011-04-07  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2011-03-17  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/48141
+	* gcc.dg/pr48141.c: New test.
+
 	2011-03-03  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/47963
diff --git a/gcc/testsuite/gcc.dg/pr48141.c b/gcc/testsuite/gcc.dg/pr48141.c
new file mode 100644
index 000000000000..c2ef79f5912e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr48141.c
@@ -0,0 +1,17 @@
+/* PR rtl-optimization/48141 */
+/* { dg-do compile } */
+/* { dg-options "-O -fno-tree-fre" } */
+
+#define A i = 0;
+#define B A A A A A A A A A A
+#define C B B B B B B B B B B
+#define D C C C C C C C C C C
+#define E D D D D D D D D D D
+
+int
+foo (void)
+{
+  volatile int i = 0;
+  E E E E E E E E E E E
+  return 0;
+}