warn & drop #__PURE__ iff IIFE is dropped (#1511)

- consolidate `side-effects` optimisations - improve string `+` optimisation - enhance literal & `conditionals` optimisations
2017-02-28 02:25:44 +08:00
parent 0b0296eb2a
commit 858e6c78a4
8 changed files with 216 additions and 99 deletions
--- a/test/compress/dead-code.js
+++ b/test/compress/dead-code.js
@@ -64,7 +64,8 @@ dead_code_constant_boolean_should_warn_more: {
        loops        : true,
        booleans     : true,
        conditionals : true,
-        evaluate     : true
+        evaluate     : true,
+        side_effects : true,
    };
    input: {
        while (!((foo && bar) || (x + "0"))) {