From patchwork Mon Mar 12 11:43:50 2012
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Subject: : Fix negative value in TEST_BIT from
 mem_overlaps_already_clobbered_arg_p()
From: mickael guene <mickael.guene@st.com>
X-Patchwork-Id: 146061
Message-Id: <4F5DE176.8020803@st.com>
To: <gcc-patches@gcc.gnu.org>
Date: Mon, 12 Mar 2012 12:43:50 +0100

Hi all,

  After applying patch from http://gcc.gnu.org/ml/gcc-patches/2012-02/msg00228.html we can
have a negative value in call to TEST_BIT() macro in mem_overlaps_already_clobbered_arg_p() function
for stored_args_map bitmap table.
  This can lead to reject a valid tail call optimization.

  This patch will ensure that i+k is positive before calling TEST_BIT() macro.

2012-03-12  Mickael Guene  <mickael.guene@st.com>

	* calls.c (mem_overlaps_already_clobbered_arg_p): Don't call TEST_BIT for
	negative value.

Regards

Mickael

--- a/gcc/calls.c	2012-03-12 10:44:27.000000000 +0100
+++ b/gcc/calls.c	2012-03-12 10:46:16.000000000 +0100
@@ -1822,7 +1822,8 @@
       unsigned HOST_WIDE_INT k;
 
       for (k = 0; k < size; k++)
-	if (i + k < stored_args_map->n_bits
+	if (i + k >= 0
+	    && i + k < stored_args_map->n_bits
 	    && TEST_BIT (stored_args_map, i + k))
 	  return true;
     }