X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=gcc%2Fsparseset.c;h=823919a886e49fd62f48bdd362dd6b1554a13a3f;hb=9d33046c199ad03cc0ba1210be7bcfbbcb136254;hp=8d7cd9373bdd6bc384d6498e854bb56565555d5a;hpb=981db194768f6990aef28c6ea50b2f37012dd92d;p=pf3gnuchains%2Fgcc-fork.git

diff --git a/gcc/sparseset.c b/gcc/sparseset.c
index 8d7cd9373bd..823919a886e 100644
--- a/gcc/sparseset.c
+++ b/gcc/sparseset.c
@@ -1,5 +1,5 @@
 /* SparseSet implementation.
-   Copyright (C) 2007 Free Software Foundation, Inc.
+   Copyright (C) 2007, 2008 Free Software Foundation, Inc.
    Contributed by Peter Bergner <bergner@vnet.ibm.com>
 
 This file is part of GCC.
@@ -18,10 +18,10 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
-#include "libiberty.h"
+#include "config.h"
+#include "system.h"
 #include "sparseset.h"
 
-
 /* Allocate and clear a n_elms SparseSet.  */
 
 sparseset
@@ -30,7 +30,12 @@ sparseset_alloc (SPARSESET_ELT_TYPE n_elms)
   unsigned int n_bytes = sizeof (struct sparseset_def)
 			 + ((n_elms - 1) * 2 * sizeof (SPARSESET_ELT_TYPE));
 
-  sparseset set = (sparseset) xmalloc (n_bytes);
+  /* We use xcalloc rather than xmalloc to silence some valgrind uninitialized
+     read errors when accessing set->sparse[n] when "n" is not, and never has
+     been, in the set.  These uninitialized reads are expected, by design and
+     harmless.  If this turns into a performance problem due to some future
+     additional users of sparseset, we can revisit this decision.  */
+  sparseset set = (sparseset) xcalloc (1, n_bytes);
   set->dense = &(set->elms[0]);
   set->sparse = &(set->elms[n_elms]);
   set->size = n_elms;