From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 10 May 2011 08:47:09 +0000 (+0200)
Subject: backport: re PR tree-optimization/48837 (Wrong optimization of recursive function... 
X-Git-Tag: releases/gcc-4.4.7~409
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c3811910a67506fb4ac3c7b0d5da745fdd731d8a;p=thirdparty%2Fgcc.git

backport: re PR tree-optimization/48837 (Wrong optimization of recursive function calls)

	Backported from mainline
	2011-05-07  Zdenek Dvorak  <ook@ucw.cz>

	PR tree-optimization/48837
	* tree-tailcall.c (tree_optimize_tail_calls_1): Do not mark tailcalls
	when accumulator transformation is performed.

	* gcc.dg/pr48837.c: New testcase.

From-SVN: r173611
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fe0fc6a1146f..145b36ab238b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2011-05-10  Jakub Jelinek  <jakub@redhat.com>
+
+	Backported from mainline
+	2011-05-07  Zdenek Dvorak  <ook@ucw.cz>
+
+	PR tree-optimization/48837
+	* tree-tailcall.c (tree_optimize_tail_calls_1): Do not mark tailcalls
+	when accumulator transformation is performed.
+
 2011-05-05  Jason Merrill  <jason@redhat.com>
 
 	PR c++/40975
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e22b269a4a20..8e1852893d18 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2011-05-10  Jakub Jelinek  <jakub@redhat.com>
+
+	Backported from mainline
+	2011-05-07  Zdenek Dvorak  <ook@ucw.cz>
+
+	PR tree-optimization/48837
+	* gcc.dg/pr48837.c: New testcase.
+
 2011-05-09  Jason Merrill  <jason@redhat.com>
 
 	* g++.dg/template/nontype23.C: New.
diff --git a/gcc/testsuite/gcc.dg/pr48837.c b/gcc/testsuite/gcc.dg/pr48837.c
new file mode 100644
index 000000000000..ffc65b9dc8c5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr48837.c
@@ -0,0 +1,30 @@
+/* PR tree-optimization/48837 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+void abort (void);
+
+__attribute__((noinline))
+int baz(void)
+{
+  return 1;
+}
+
+inline const int *bar(const int *a, const int *b)
+{
+ return *a ? a : b;
+}
+
+int foo(int a, int b)
+{
+   return a || b ? baz() : foo(*bar(&a, &b), 1) + foo(1, 0);
+}
+
+int main(void)
+{
+ if (foo(0, 0) != 2)
+   abort();
+
+ return 0;
+}
+
diff --git a/gcc/tree-tailcall.c b/gcc/tree-tailcall.c
index 9d2513d271dc..55cdc51042ca 100644
--- a/gcc/tree-tailcall.c
+++ b/gcc/tree-tailcall.c
@@ -953,6 +953,14 @@ tree_optimize_tail_calls_1 (bool opt_tailcalls)
 					     integer_one_node);
     }
 
+  if (a_acc || m_acc)
+    {
+      /* When the tail call elimination using accumulators is performed,
+	 statements adding the accumulated value are inserted at all exits.
+	 This turns all other tail calls to non-tail ones.  */
+      opt_tailcalls = false;
+    }
+
   for (; tailcalls; tailcalls = next)
     {
       next = tailcalls->next;