re PR c/10178 (ICE in tree_low_cst)

	PR c/10178
	* stmt.c (expand_end_case_type): Check for overflow in range when
	determining whether to use a bit-test implementation.

	* gcc.c-torture/compile/20030323-1.c: New test case.

From-SVN: r64757

gcc/ChangeLog

+2003-03-23  Roger Sayle  <roger@eyesopen.com>
+
+	PR c/10178
+	* stmt.c (expand_end_case_type): Check for overflow in range when
+	determining whether to use a bit-test implementation.
+
 2003-03-23  Richard Henderson  <rth@redhat.com>
 
 	* cfgcleanup.c (try_optimize_cfg): Allow merging of tablejumps

gcc/stmt.c

@@ -5505,6 +5505,7 @@ expand_end_case_type (orig_index, orig_type)
       else if (CASE_USE_BIT_TESTS
 	       && ! TREE_CONSTANT (index_expr)
 	       && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
+	       && compare_tree_int (range, 0) > 0
 	       && lshift_cheap_p ()
 	       && ((uniq == 1 && count >= 3)
 		   || (uniq == 2 && count >= 5)

gcc/testsuite/ChangeLog

+2003-03-23  Roger Sayle  <roger@eyesopen.com>
+
+	* gcc.c-torture/compile/20030323-1.c: New test case.
+
 2003-03-22  Ulrich Weigand  <uweigand@de.ibm.com>
 
 	* gcc.dg/20030321-1.c: New test.

gcc/testsuite/gcc.c-torture/compile/20030323-1.c

+/* PR c/10178.  The following code would ICE because we didn't check for
+   overflow when computing the range of the switch-statment, and therefore
+   decided it could be implemented using bit-tests.  */
+
+int
+banana(long citron)
+{
+  switch (citron) {
+    case 0x80000000:
+    case 0x40000:
+    case 0x40001:
+      return 1;
+      break;
+  }
+  return 0;
+}
+