diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 06515889f6a..9044a6c9058 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2013-11-05  Marc Glisse  <marc.glisse@inria.fr>
+
+	* tree-ssa-alias.h (ranges_overlap_p): Handle negative offsets.
+	* tree-ssa-alias.c (ao_ref_init_from_ptr_and_size): Likewise.
+
 2013-11-05  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/58984
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d95fc2c64de..9235430b8e5 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2013-11-05  Marc Glisse  <marc.glisse@inria.fr>
+
+	* gcc.dg/tree-ssa/alias-26.c: New file.
+
 2013-11-05  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/58984
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/alias-26.c b/gcc/testsuite/gcc.dg/tree-ssa/alias-26.c
new file mode 100644
index 00000000000..a1eb8f7d0a8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/alias-26.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+void f (const char *c, int *i)
+{
+  *i = 42;
+  __builtin_memcpy (i - 1, c, sizeof (int));
+  if (*i != 42) __builtin_abort();
+}
+
+/* { dg-final { scan-tree-dump-not "abort" "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
+
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index efc08c20991..6f7e8534803 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -559,7 +559,7 @@ ao_ref_alias_set (ao_ref *ref)
 }
 
 /* Init an alias-oracle reference representation from a gimple pointer
-   PTR and a gimple size SIZE in bytes.  If SIZE is NULL_TREE the the
+   PTR and a gimple size SIZE in bytes.  If SIZE is NULL_TREE then the
    size is assumed to be unknown.  The access is assumed to be only
    to or after of the pointer target, not before it.  */
 
@@ -576,11 +576,11 @@ ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size)
 	ptr = gimple_assign_rhs1 (stmt);
       else if (is_gimple_assign (stmt)
 	       && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
-	       && host_integerp (gimple_assign_rhs2 (stmt), 0)
-	       && (t1 = int_cst_value (gimple_assign_rhs2 (stmt))) >= 0)
+	       && TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST)
 	{
 	  ptr = gimple_assign_rhs1 (stmt);
-	  extra_offset = BITS_PER_UNIT * t1;
+	  extra_offset = BITS_PER_UNIT
+			 * int_cst_value (gimple_assign_rhs2 (stmt));
 	}
     }
 
diff --git a/gcc/tree-ssa-alias.h b/gcc/tree-ssa-alias.h
index 831cffebecb..581cd82a5f3 100644
--- a/gcc/tree-ssa-alias.h
+++ b/gcc/tree-ssa-alias.h
@@ -146,18 +146,18 @@ extern GTY(()) struct pt_solution ipa_escaped_pt;
    range is open-ended.  Otherwise return false.  */
 
 static inline bool
-ranges_overlap_p (unsigned HOST_WIDE_INT pos1,
+ranges_overlap_p (HOST_WIDE_INT pos1,
 		  unsigned HOST_WIDE_INT size1,
-		  unsigned HOST_WIDE_INT pos2,
+		  HOST_WIDE_INT pos2,
 		  unsigned HOST_WIDE_INT size2)
 {
   if (pos1 >= pos2
       && (size2 == (unsigned HOST_WIDE_INT)-1
-	  || pos1 < (pos2 + size2)))
+	  || pos1 < (pos2 + (HOST_WIDE_INT) size2)))
     return true;
   if (pos2 >= pos1
       && (size1 == (unsigned HOST_WIDE_INT)-1
-	  || pos2 < (pos1 + size1)))
+	  || pos2 < (pos1 + (HOST_WIDE_INT) size1)))
     return true;
 
   return false;