re PR middle-end/37882 (Bitfield miscompilation)

	PR middle-end/37882
	* fold-const.c (build_range_type): For 1 .. signed_max
	range call build_nonstandard_inter_type if signed_type_for
	returned a type with bigger precision.

	* gcc.c-torture/execute/pr37882.c: New test.

From-SVN: r141303

gcc/ChangeLog

+2008-10-22  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/37882
+	* fold-const.c (build_range_type): For 1 .. signed_max
+	range call build_nonstandard_inter_type if signed_type_for
+	returned a type with bigger precision.
+
 2008-10-22  Richard Guenther  <rguenther@suse.de>
 
 	* tree.def (COMPLEX_TYPE): Constrain element type.

gcc/fold-const.c

@@ -4503,7 +4503,12 @@ build_range_check (tree type, tree exp, int in_p, tree low, tree high)
 	{
 	  if (TYPE_UNSIGNED (etype))
 	    {
-	      etype = signed_type_for (etype);
+	      tree signed_etype = signed_type_for (etype);
+	      if (TYPE_PRECISION (signed_etype) != TYPE_PRECISION (etype))
+		etype
+		  = build_nonstandard_integer_type (TYPE_PRECISION (etype), 0);
+	      else
+		etype = signed_etype;
 	      exp = fold_convert (etype, exp);
 	    }
 	  return fold_build2 (GT_EXPR, type, exp,

gcc/testsuite/ChangeLog

+2008-10-22  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/37882
+	* gcc.c-torture/execute/pr37882.c: New test.
+
 2008-10-22  Manuel López-Ibáñez  <manu@gcc.gnu.org>
 
 	PR c/30949

gcc/testsuite/gcc.c-torture/execute/pr37882.c

+/* PR middle-end/37882 */
+
+struct S
+{
+  int a : 21;
+  unsigned char b : 3;
+} s;
+
+int
+main ()
+{
+  s.b = 4;
+  if (s.b > 0 && s.b < 4)
+    __builtin_abort ();
+  return 0;
+}