re PR tree-optimization/66863 (wrong code at -Os and above on x86_64-linux-gnu)

2015-07-14  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/66863
	* tree-vrp.c (register_edge_assert_for_2): Properly restrict
	what we record for conversion use stmt lhs inequalities.

	* gcc.dg/torture/pr66863.c: New testcase.

From-SVN: r225768

gcc/ChangeLog

 2015-07-14  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/66863
+	* tree-vrp.c (register_edge_assert_for_2): Properly restrict
+	what we record for conversion use stmt lhs inequalities.
+
+2015-07-14  Richard Biener  <rguenther@suse.de>
+
 	* genmatch.c (dt_node::gen_kids_1): Fix case label indenting.
 	(decision_tree::gen_gimple): Likewise.
 

gcc/testsuite/ChangeLog

+2015-07-14  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/66863
+	* gcc.dg/torture/pr66863.c: New testcase.
+
 2015-07-13  Patrick Palka  <ppalka@gcc.gnu.org>
 
 	PR c++/65186

gcc/testsuite/gcc.dg/torture/pr66863.c

+/* { dg-do run } */
+
+int a, b;
+
+int
+fn1 (int p1)
+{
+  if (p1 < -2147483647) 
+    return 0;
+  else 
+    return 1;
+}
+
+int
+fn2 (int p1, short p2)
+{
+  return p2 ? p1 % p2 : 0; 
+}
+
+int
+main ()
+{
+  b = fn2 (fn1 (a), a);
+  return 0;
+}

gcc/tree-vrp.c

@@ -5381,7 +5381,17 @@ register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
 	      cst = int_const_binop (code, val, cst);
 	    }
 	  else if (CONVERT_EXPR_CODE_P (code))
-	    cst = fold_convert (TREE_TYPE (name2), val);
+	    {
+	      /* For truncating conversions require that the constant
+	         fits in the truncated type if we are going to record
+		 an inequality.  */
+	      if (comp_code == NE_EXPR
+		  && (TYPE_PRECISION (TREE_TYPE (name2))
+		      < TYPE_PRECISION (TREE_TYPE (name)))
+		  && ! int_fits_type_p (val, TREE_TYPE (name2)))
+		continue;
+	      cst = fold_convert (TREE_TYPE (name2), val);
+	    }
 	  else
 	    continue;