enhance if_return (#3232)

2018-08-21 18:34:16 +08:00
parent 18c1c9b38a
commit 57fb58b263
2 changed files with 161 additions and 0 deletions
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1699,6 +1699,19 @@ merge(Compressor.prototype, {
                        continue;
                    }

+                    if (ab && !stat.alternative && stat.body instanceof AST_BlockStatement && next instanceof AST_Jump) {
+                        var negated = stat.condition.negate(compressor);
+                        if (negated.print_to_string().length <= stat.condition.print_to_string().length) {
+                            CHANGED = true;
+                            stat = stat.clone();
+                            stat.condition = negated;
+                            statements[j] = stat.body;
+                            stat.body = next;
+                            statements[i] = stat.transform(compressor);
+                            continue;
+                        }
+                    }
+
                    var ab = aborts(stat.alternative);
                    if (can_merge_flow(ab)) {
                        if (ab.label) {