introduce `assignments` (#3345)

6 files changed, 95 insertions, 2 deletions

diff --git a/test/compress/asm.js b/test/compress/asm.js
index d7b1b62b..cebe6838 100644
--- a/test/compress/asm.js
+++ b/test/compress/asm.js
@@ -1,5 +1,6 @@
 asm_mixed: {
     options = {
+        assignments: true,
         booleans: true,
         comparisons: true,
         conditionals: true,
diff --git a/test/compress/assignment.js b/test/compress/assignment.js
index 903380a9..ba412583 100644
--- a/test/compress/assignment.js
+++ b/test/compress/assignment.js
@@ -1,5 +1,6 @@
 op_equals_left_local_var: {
     options = {
+        assignments: true,
         evaluate: true,
     }
     input: {
@@ -60,6 +61,7 @@ op_equals_left_local_var: {
 
 op_equals_right_local_var: {
     options = {
+        assignments: true,
         evaluate: true,
     }
     input: {
@@ -123,6 +125,7 @@ op_equals_right_local_var: {
 }
 op_equals_left_global_var: {
     options = {
+        assignments: true,
         evaluate: true,
     }
     input: {
@@ -179,6 +182,7 @@ op_equals_left_global_var: {
 
 op_equals_right_global_var: {
     options = {
+        assignments: true,
         evaluate: true,
     }
     input: {
@@ -236,3 +240,52 @@ op_equals_right_global_var: {
         x = g() &   x;
     }
 }
+
+increment_decrement_1: {
+    options = {
+        assignments: true,
+        reduce_vars: true,
+    }
+    input: {
+        console.log(function(a) {
+            a += 1;
+            a -= 1;
+            return a;
+        }(42));
+    }
+    expect: {
+        console.log(function(a){
+            ++a;
+            --a;
+            return a;
+        }(42));
+    }
+    expect_stdout: "42"
+}
+
+increment_decrement_2: {
+    options = {
+        assignments: true,
+        passes: 2,
+        reduce_vars: true,
+    }
+    input: {
+        console.log(function(a) {
+            a = a + 1;
+            a = a - 1;
+            a += 1;
+            a -= 1;
+            return a;
+        }(42));
+    }
+    expect: {
+        console.log(function(a){
+            ++a;
+            --a;
+            ++a;
+            --a;
+            return a;
+        }(42));
+    }
+    expect_stdout: "42"
+}
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index 6c867123..a858e000 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -944,7 +944,7 @@ collapse_vars_misc1: {
         function f5(x) { var z = foo(); return (5 - window.x) / z }
         function f6() { return window.a * window.z && zap() }
         function f7() { var b = window.a * window.z; return b + b }
-        function f8() { var b = window.a * window.z; return b + (b + 5) }
+        function f8() { var b = window.a * window.z; return b + (5 + b) }
         function f9() { var b = window.a * window.z; return bar() || b }
         function f10(x) { var a = 5; return a += 3; }
         function f11(x) { var a = 5; return a += 2; }
diff --git a/test/compress/conditionals.js b/test/compress/conditionals.js
index d6d47c41..78c0ca24 100644
--- a/test/compress/conditionals.js
+++ b/test/compress/conditionals.js
@@ -1367,6 +1367,7 @@ cond_seq_assign_2: {
 
 cond_seq_assign_3: {
     options = {
+        assignments: true,
         conditionals: true,
     }
     input: {
diff --git a/test/compress/evaluate.js b/test/compress/evaluate.js
index 23785284..a740cd82 100644
--- a/test/compress/evaluate.js
+++ b/test/compress/evaluate.js
@@ -1540,7 +1540,7 @@ issue_2926_2: {
     expect_stdout: "function"
 }
 
-issue_2968: {
+issue_2968_1: {
     options = {
         collapse_vars: true,
         evaluate: true,
@@ -1571,6 +1571,39 @@ issue_2968: {
     expect_stdout: "PASS"
 }
 
+issue_2968_2: {
+    options = {
+        assignments: true,
+        collapse_vars: true,
+        evaluate: true,
+        inline: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var c = "FAIL";
+        (function() {
+            (function(a, b) {
+                a <<= 0;
+                a && (a[(c = "PASS", 0 >>> (b += 1))] = 0);
+            })(42, -42);
+        })();
+        console.log(c);
+    }
+    expect: {
+        var c = "FAIL";
+        (function() {
+            a = 42,
+            ((a <<= 0) && (a[(c = "PASS", 0)] = 0));
+            var a;
+        })();
+        console.log(c);
+    }
+    expect_stdout: "PASS"
+}
+
 truthy_conditionals: {
     options = {
         conditionals: true,
diff --git a/test/compress/functions.js b/test/compress/functions.js
index 4d243a81..a52796c2 100644
--- a/test/compress/functions.js
+++ b/test/compress/functions.js
@@ -358,6 +358,7 @@ inner_ref: {
 
 issue_2107: {
     options = {
+        assignments: true,
         collapse_vars: true,
         inline: true,
         passes: 3,
@@ -387,6 +388,7 @@ issue_2107: {
 
 issue_2114_1: {
     options = {
+        assignments: true,
         collapse_vars: true,
         if_return: true,
         inline: true,
@@ -419,6 +421,7 @@ issue_2114_1: {
 
 issue_2114_2: {
     options = {
+        assignments: true,
         collapse_vars: true,
         if_return: true,
         inline: true,
@@ -1223,6 +1226,7 @@ issue_2630_1: {
 
 issue_2630_2: {
     options = {
+        assignments: true,
         collapse_vars: true,
         inline: true,
         passes: 2,
@@ -1320,6 +1324,7 @@ issue_2630_4: {
 
 issue_2630_5: {
     options = {
+        assignments: true,
         collapse_vars: true,
         inline: true,
         reduce_vars: true,