Daily bump.

[pf3gnuchains/gcc-fork.git] / gcc / sparseset.c

diff --git a/gcc/sparseset.c b/gcc/sparseset.c
index f556c4d..823919a 100644 (file)
--- 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.
@@ -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;