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

	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: r173534

gcc/ChangeLog

+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.
+
 2011-05-06  Jan Hubicka  <jh@suse.cz>
 
 	* i386.h (ix86_tune_indices): Add X86_TUNE_SOFTWARE_PREFETCHING_BENEFICIAL.

gcc/testsuite/ChangeLog

+2011-05-07  Zdenek Dvorak  <ook@ucw.cz>
+
+	PR tree-optimization/48837
+	* gcc.dg/pr48837.c: New testcase.
+
 2011-05-06  Jason Merrill  <jason@redhat.com>
 
 	* g++.dg/cpp0x/constexpr-condition2.C: New.

gcc/testsuite/gcc.dg/pr48837.c

+/* 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;
+}
+

gcc/tree-tailcall.c

@@ -1021,6 +1021,14 @@ 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;