Optimize if_return for single if/return cases.

Fixes #1089

1 files changed, 207 insertions, 0 deletions

diff --git a/test/compress/if_return.js b/test/compress/if_return.js
new file mode 100644
index 00000000..78a6e818
--- /dev/null
+++ b/test/compress/if_return.js
@@ -0,0 +1,207 @@
+if_return_1: {
+    options = {
+        if_return    : true,
+        sequences    : true,
+        conditionals : true,
+        comparisons  : true,
+        evaluate     : true,
+        booleans     : true,
+        unused       : true,
+        side_effects : true,
+        dead_code    : true,
+    }
+    input: {
+        function f(x) {
+            if (x) {
+                return true;
+            }
+        }
+    }
+    expect: {
+        function f(x){if(x)return!0}
+    }
+}
+
+if_return_2: {
+    options = {
+        if_return    : true,
+        sequences    : true,
+        conditionals : true,
+        comparisons  : true,
+        evaluate     : true,
+        booleans     : true,
+        unused       : true,
+        side_effects : true,
+        dead_code    : true,
+    }
+    input: {
+        function f(x, y) {
+            if (x)
+                return 3;
+            if (y)
+                return c();
+        }
+    }
+    expect: {
+        function f(x,y){return x?3:y?c():void 0}
+    }
+}
+
+if_return_3: {
+    options = {
+        if_return    : true,
+        sequences    : true,
+        conditionals : true,
+        comparisons  : true,
+        evaluate     : true,
+        booleans     : true,
+        unused       : true,
+        side_effects : true,
+        dead_code    : true,
+    }
+    input: {
+        function f(x) {
+            a();
+            if (x) {
+                b();
+                return false;
+            }
+        }
+    }
+    expect: {
+        function f(x){if(a(),x)return b(),!1}
+    }
+}
+
+if_return_4: {
+    options = {
+        if_return    : true,
+        sequences    : true,
+        conditionals : true,
+        comparisons  : true,
+        evaluate     : true,
+        booleans     : true,
+        unused       : true,
+        side_effects : true,
+        dead_code    : true,
+    }
+    input: {
+        function f(x, y) {
+            a();
+            if (x) return 3;
+            b();
+            if (y) return c();
+        }
+    }
+    expect: {
+        function f(x,y){return a(),x?3:(b(),y?c():void 0)}
+    }
+}
+
+if_return_5: {
+    options = {
+        if_return    : true,
+        sequences    : true,
+        conditionals : true,
+        comparisons  : true,
+        evaluate     : true,
+        booleans     : true,
+        unused       : true,
+        side_effects : true,
+        dead_code    : true,
+    }
+    input: {
+        function f() {
+            if (x)
+                return;
+            return 7;
+            if (y)
+                return j;
+        }
+    }
+    expect: {
+        function f(){if(!x)return 7}
+    }
+}
+
+if_return_6: {
+    options = {
+        if_return    : true,
+        sequences    : true,
+        conditionals : true,
+        comparisons  : true,
+        evaluate     : true,
+        booleans     : true,
+        unused       : true,
+        side_effects : true,
+        dead_code    : true,
+    }
+    input: {
+        function f(x) {
+          return x ? true : void 0;
+          return y;
+        }
+    }
+    expect: {
+        // suboptimal
+        function f(x){return!!x||void 0}
+    }
+}
+
+if_return_7: {
+    options = {
+        if_return    : true,
+        sequences    : true,
+        conditionals : true,
+        comparisons  : true,
+        evaluate     : true,
+        booleans     : true,
+        unused       : true,
+        side_effects : true,
+        dead_code    : true,
+    }
+    input: {
+        function f(x) {
+            if (x) {
+                return true;
+            }
+            foo();
+            bar();
+        }
+    }
+    expect: {
+        // suboptimal
+        function f(x){return!!x||(foo(),void bar())}
+    }
+}
+
+issue_1089: {
+    options = {
+        if_return    : true,
+        sequences    : true,
+        conditionals : true,
+        comparisons  : true,
+        evaluate     : true,
+        booleans     : true,
+        unused       : true,
+        side_effects : true,
+        dead_code    : true,
+    }
+    input: {
+        function x() {
+            var f = document.getElementById("fname");
+            if (f.files[0].size > 12345) {
+                alert("alert");
+                f.focus();
+                return false;
+            }
+        }
+    }
+    expect: {
+        function x() {
+            var f = document.getElementById("fname");
+            if (f.files[0].size > 12345)
+                return alert("alert"), f.focus(), !1;
+        }
+    }
+}