From: Jan Hubicka <jh@suse.cz>
Date: Tue, 1 Jun 2010 21:55:49 +0000 (+0200)
Subject: ipa-pure-const.c (local_pure_const): Do NORETURN discovery.
X-Git-Tag: releases/gcc-4.6.0~6848
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=73add7fe2951139ec8508968888c1f5b12eceae7;p=thirdparty%2Fgcc.git

ipa-pure-const.c (local_pure_const): Do NORETURN discovery.

	* ipa-pure-const.c (local_pure_const): Do NORETURN discovery.

	* testsuite/gcc.dg/noreturn-8.c: New testcase.

From-SVN: r160124
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 513b3181ac60..a87a41da66ab 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2010-06-01  Jan Hubicka  <jh@suse.cz>
+
+	* ipa-pure-const.c (local_pure_const): Do NORETURN discovery.
+
 2010-06-01  Jan Hubicka  <jh@suse.cz>
 
 	* tree-cfgcleanup.c (fixup_noreturn_call): Break out from ...;
diff --git a/gcc/ipa-pure-const.c b/gcc/ipa-pure-const.c
index df2f8c85312d..d785389191a8 100644
--- a/gcc/ipa-pure-const.c
+++ b/gcc/ipa-pure-const.c
@@ -1362,6 +1362,27 @@ local_pure_const (void)
       && !warn_suggest_attribute_pure
       && skip)
     return 0;
+
+  /* First do NORETURN discovery.  */
+  if (!skip && !TREE_THIS_VOLATILE (current_function_decl)
+      && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0)
+    {
+      if (warn_missing_noreturn
+	  && !lang_hooks.missing_noreturn_ok_p (cfun->decl))
+	warning_at (DECL_SOURCE_LOCATION (cfun->decl), OPT_Wmissing_noreturn,
+		    "function might be possible candidate "
+		    "for attribute %<noreturn%>");
+      if (dump_file)
+        fprintf (dump_file, "Function found to be noreturn: %s\n",
+	         lang_hooks.decl_printable_name (current_function_decl, 2));
+
+      /* Update declaration and reduce profile to executed once.  */
+      TREE_THIS_VOLATILE (current_function_decl) = 1;
+      if (node->frequency > NODE_FREQUENCY_EXECUTED_ONCE)
+        node->frequency = NODE_FREQUENCY_EXECUTED_ONCE;
+
+      changed = true;
+    }
   l = analyze_function (node, false);
 
   switch (l->pure_const_state)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index efbec90be930..cd4fdc359fc3 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2010-05-31 Jan Hubicka  <jh@suse.cz>
+
+	* testsuite/gcc.dg/noreturn-8.c: New testcase.
+
 2010-05-31 Jan Hubicka  <jh@suse.cz>
 
 	* testsuite/gcc.dg/lto/noreturn-1_1.c: Remove dg-do annotations.
diff --git a/gcc/testsuite/gcc.dg/noreturn-8.c b/gcc/testsuite/gcc.dg/noreturn-8.c
new file mode 100644
index 000000000000..50765da37ef4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/noreturn-8.c
@@ -0,0 +1,16 @@
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+void exit (int);
+void noreturn_autodetection_failed ();
+__attribute__ ((noinline))
+detect_noreturn ()
+{
+  exit (0);
+}
+int
+main (void)
+{
+  detect_noreturn ();
+  noreturn_autodetection_failed ();
+  return 0;
+}