diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8ac9e95eb57..493b7ec3e90 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2009-04-06  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* stor-layout.c (set_sizetype): Use the full precision of their
+	machine mode for bitsize types.
+
 2009-04-06  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* config/i386/i386.md: Revert 2 accidental checkins.
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index e7036827a0c..c2d367f38a7 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -2046,15 +2046,18 @@ initialize_sizetypes (bool signed_p)
 void
 set_sizetype (tree type)
 {
+  tree t;
   int oprecision = TYPE_PRECISION (type);
   /* The *bitsizetype types use a precision that avoids overflows when
      calculating signed sizes / offsets in bits.  However, when
      cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
      precision.  */
-  int precision = MIN (MIN (oprecision + BITS_PER_UNIT_LOG + 1,
-			    MAX_FIXED_MODE_SIZE),
-		       2 * HOST_BITS_PER_WIDE_INT);
-  tree t;
+  int precision
+    = MIN (oprecision + BITS_PER_UNIT_LOG + 1, MAX_FIXED_MODE_SIZE);
+  precision
+    = GET_MODE_PRECISION (smallest_mode_for_size (precision, MODE_INT));
+  if (precision > HOST_BITS_PER_WIDE_INT * 2)
+    precision = HOST_BITS_PER_WIDE_INT * 2;
 
   gcc_assert (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (sizetype));