re PR middle-end/46019 (x / (0x200000000ULL << y) miscompilation with 32-bit HWI)

	PR middle-end/46019
	* fold-const.c (fold_binary_loc): If integer_pow2p has
	TREE_INT_CST_LOW zero, look at TREE_INT_CST_HIGH.

	* gcc.c-torture/execute/pr46019.c: New test.

From-SVN: r165610

gcc/ChangeLog

+2010-10-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/46019
+	* fold-const.c (fold_binary_loc): If integer_pow2p has
+	TREE_INT_CST_LOW zero, look at TREE_INT_CST_HIGH.
+
 2010-10-18  Basile Starynkevitch  <basile@starynkevitch.net>
 	    Jeremie Salvucci  <jeremie.salvucci@free.fr>
 

gcc/fold-const.c

@@ -11611,7 +11611,13 @@ fold_binary_loc (location_t loc,
 	  if (integer_pow2p (sval) && tree_int_cst_sgn (sval) > 0)
 	    {
 	      tree sh_cnt = TREE_OPERAND (arg1, 1);
-	      unsigned long pow2 = exact_log2 (TREE_INT_CST_LOW (sval));
+	      unsigned long pow2;
+
+	      if (TREE_INT_CST_LOW (sval))
+		pow2 = exact_log2 (TREE_INT_CST_LOW (sval));
+	      else
+		pow2 = exact_log2 (TREE_INT_CST_HIGH (sval))
+		       + HOST_BITS_PER_WIDE_INT;
 
 	      if (strict_overflow_p)
 		fold_overflow_warning (("assuming signed overflow does not "

gcc/testsuite/ChangeLog

+2010-10-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/46019
+	* gcc.c-torture/execute/pr46019.c: New test.
+
 2010-10-17  Nicola Pero  <nicola.pero@meta-innovation.com>
 	
 	Merge from 'apple/trunk' branch on FSF servers.

gcc/testsuite/gcc.c-torture/execute/pr46019.c

+/* PR middle-end/46019 */
+
+extern void abort (void);
+
+int
+main (void)
+{
+  unsigned long long l = 0x40000000000ULL;
+  int n;
+  for (n = 0; n < 8; n++)
+    if (l / (0x200000000ULL << n) != (0x200 >> n))
+      abort ();
+  return 0;
+}