Make division by zero error check more accurate

For division (rather than modulus) we should check the double
value, otherwise the result might be zero after integer truncation,
but not zero as a floating point value.

Author: nikic

Zend/zend_compile.c

@@ -7259,7 +7259,8 @@ ZEND_API zend_bool zend_binary_op_produces_error(uint32_t opcode, zval *op1, zva
 		return 1;
 	}
 
-	if ((opcode == ZEND_DIV || opcode == ZEND_MOD) && zval_get_long(op2) == 0) {
+	if ((opcode == ZEND_MOD && zval_get_long(op2) == 0)
+			|| (opcode == ZEND_DIV && zval_get_double(op2) == 0.0)) {
 		/* Division by zero throws an error. */
 		return 1;
 	}