Fix PR 10153: tail recusion for vector types.

The problem here is we try to an initialized value
from a scalar constant. For vectors we need to do
a vect_dup instead.  This fixes that issue by using
build_{one,zero}_cst instead of integer_{one,zero}_node
when calling create_tailcall_accumulator.

Changes from v1:
* v2: Use build_{one,zero}_cst and get the correct type before.

OK? Bootstrapped and tested on aarch64-linux-gnu with no regressions.

gcc/ChangeLog:

	PR tree-optimization/10153
	* tree-tailcall.c (create_tailcall_accumulator):
	Don't call fold_convert as the type should be correct already.
	(tree_optimize_tail_calls_1): Use build_{one,zero}_cst instead
	of integer_{one,zero}_node for the call of create_tailcall_accumulator.

gcc/testsuite/ChangeLog:

	PR tree-optimization/10153
	* gcc.c-torture/compile/pr10153-1.c: New test.
	* gcc.c-torture/compile/pr10153-2.c: New test.

gcc/testsuite/gcc.c-torture/compile/pr10153-1.c

@@ -0,0 +1,7 @@
+typedef int V __attribute__ ((vector_size (2 * sizeof (int))));
+V
+foo (void)
+{
+  V v = { };
+  return v - foo();
+}

gcc/testsuite/gcc.c-torture/compile/pr10153-2.c

@@ -0,0 +1,9 @@
+typedef int V __attribute__ ((vector_size (2 * sizeof (int))));
+V
+foo (int t)
+{
+  if (t < 10)
+    return (V){1, 1};
+  V v = { };
+  return v - foo(t - 1);
+}

gcc/tree-tailcall.c

@@ -1079,8 +1079,7 @@ create_tailcall_accumulator (const char *label, basic_block bb, tree init)
   gphi *phi;
 
   phi = create_phi_node (tmp, bb);
-  /* RET_TYPE can be a float when -ffast-maths is enabled.  */
-  add_phi_arg (phi, fold_convert (ret_type, init), single_pred_edge (bb),
+  add_phi_arg (phi, init, single_pred_edge (bb),
 	       UNKNOWN_LOCATION);
   return PHI_RESULT (phi);
 }
@@ -1157,14 +1156,17 @@ tree_optimize_tail_calls_1 (bool opt_tailcalls)
 	      }
 	  phis_constructed = true;
 	}
+      tree ret_type = TREE_TYPE (DECL_RESULT (current_function_decl));
+      if (POINTER_TYPE_P (ret_type))
+	ret_type = sizetype;
 
       if (act->add && !a_acc)
 	a_acc = create_tailcall_accumulator ("add_acc", first,
-					     integer_zero_node);
+					     build_zero_cst (ret_type));
 
       if (act->mult && !m_acc)
 	m_acc = create_tailcall_accumulator ("mult_acc", first,
-					     integer_one_node);
+					     build_one_cst (ret_type));
     }
 
   if (a_acc || m_acc)