optimise binary operands with evaluate() (#1427)

- remove call to evaluate() in is_constant() and let nested optimize() does its job instead
- reject RegExp in is_constant() and remove special case logic under collapse_vars
- operands to conditionals optimisation are now always evaluate()-ed
- throw error in constant_value() instead of returning undefined to catch possible bugs, similar to make_node_from_constant()
- optimise binary boolean operators under `evaluate` instead of `conditionals`

3 files changed, 219 insertions, 172 deletions

diff --git a/test/compress/conditionals.js b/test/compress/conditionals.js
index 35cb26f7..d88c5b90 100644
--- a/test/compress/conditionals.js
+++ b/test/compress/conditionals.js
@@ -635,166 +635,6 @@ ternary_boolean_alternative: {
     }
 }
 
-conditional_and: {
-    options = {
-        conditionals: true,
-        evaluate    : true
-    };
-    input: {
-        var a;
-        // compress these
-
-        a = true     && condition;
-        a = 1        && console.log("a");
-        a = 2 * 3    && 2 * condition;
-        a = 5 == 5   && condition + 3;
-        a = "string" && 4 - condition;
-        a = 5 + ""   && condition / 5;
-        a = -4.5     && 6 << condition;
-        a = 6        && 7;
-
-        a = false     && condition;
-        a = NaN       && console.log("b");
-        a = 0         && console.log("c");
-        a = undefined && 2 * condition;
-        a = null      && condition + 3;
-        a = 2 * 3 - 6 && 4 - condition;
-        a = 10 == 7   && condition / 5;
-        a = !"string" && 6 % condition;
-        a = 0         && 7;
-
-        // don't compress these
-
-        a = condition        && true;
-        a = console.log("a") && 2;
-        a = 4 - condition    && "string";
-        a = 6 << condition   && -4.5;
-
-        a = condition        && false;
-        a = console.log("b") && NaN;
-        a = console.log("c") && 0;
-        a = 2 * condition    && undefined;
-        a = condition + 3    && null;
-
-    }
-    expect: {
-        var a;
-
-        a = condition;
-        a = console.log("a");
-        a = 2 * condition;
-        a = condition + 3;
-        a = 4 - condition;
-        a = condition / 5;
-        a = 6 << condition;
-        a = 7;
-
-        a = false;
-        a = NaN;
-        a = 0;
-        a = void 0;
-        a = null;
-        a = 0;
-        a = false;
-        a = false;
-        a = 0;
-
-        a = condition        && true;
-        a = console.log("a") && 2;
-        a = 4 - condition    && "string";
-        a = 6 << condition   && -4.5;
-
-        a = condition        && false;
-        a = console.log("b") && NaN;
-        a = console.log("c") && 0;
-        a = 2 * condition    && void 0;
-        a = condition + 3    && null;
-    }
-}
-
-conditional_or: {
-    options = {
-        conditionals: true,
-        evaluate    : true
-    };
-    input: {
-        var a;
-        // compress these
-
-        a = true     || condition;
-        a = 1        || console.log("a");
-        a = 2 * 3    || 2 * condition;
-        a = 5 == 5   || condition + 3;
-        a = "string" || 4 - condition;
-        a = 5 + ""   || condition / 5;
-        a = -4.5     || 6 << condition;
-        a = 6        || 7;
-
-        a = false     || condition;
-        a = 0         || console.log("b");
-        a = NaN       || console.log("c");
-        a = undefined || 2 * condition;
-        a = null      || condition + 3;
-        a = 2 * 3 - 6 || 4 - condition;
-        a = 10 == 7   || condition / 5;
-        a = !"string" || 6 % condition;
-        a = null      || 7;
-
-        a = console.log(undefined && condition || null);
-        a = console.log(undefined || condition && null);
-
-        // don't compress these
-
-        a = condition        || true;
-        a = console.log("a") || 2;
-        a = 4 - condition    || "string";
-        a = 6 << condition   || -4.5;
-
-        a = condition        || false;
-        a = console.log("b") || NaN;
-        a = console.log("c") || 0;
-        a = 2 * condition    || undefined;
-        a = condition + 3    || null;
-
-    }
-    expect: {
-        var a;
-
-        a = true;
-        a = 1;
-        a = 6;
-        a = true;
-        a = "string";
-        a = "5";
-        a = -4.5;
-        a = 6;
-
-        a = condition;
-        a = console.log("b");
-        a = console.log("c");
-        a = 2 * condition;
-        a = condition + 3;
-        a = 4 - condition;
-        a = condition / 5;
-        a = 6 % condition;
-        a = 7;
-
-        a = console.log(null);
-        a = console.log(condition && null);
-
-        a = condition        || true;
-        a = console.log("a") || 2;
-        a = 4 - condition    || "string";
-        a = 6 << condition   || -4.5;
-
-        a = condition        || false;
-        a = console.log("b") || NaN;
-        a = console.log("c") || 0;
-        a = 2 * condition    || void 0;
-        a = condition + 3    || null;
-    }
-}
-
 trivial_boolean_ternary_expressions : {
     options = {
         conditionals: true,
@@ -906,3 +746,26 @@ issue_1154: {
         function g6() { return g(), "number"; }
     }
 }
+
+no_evaluate: {
+    options = {
+        conditionals: true,
+        evaluate    : false
+    }
+    input: {
+        function f(b) {
+            a = b ? !0 : !0;
+            a = b ? ~1 : ~1;
+            a = b ? -2 : -2;
+            a = b ? +3 : +3;
+        }
+    }
+    expect: {
+        function f(b) {
+            a = !0;
+            a = ~1;
+            a = -2;
+            a = +3;
+        }
+    }
+}
diff --git a/test/compress/evaluate.js b/test/compress/evaluate.js
index c74c7b24..0ff157dc 100644
--- a/test/compress/evaluate.js
+++ b/test/compress/evaluate.js
@@ -1,3 +1,187 @@
+and: {
+    options = {
+        evaluate: true
+    }
+    input: {
+        var a;
+        // compress these
+
+        a = true     && condition;
+        a = 1        && console.log("a");
+        a = 2 * 3    && 2 * condition;
+        a = 5 == 5   && condition + 3;
+        a = "string" && 4 - condition;
+        a = 5 + ""   && condition / 5;
+        a = -4.5     && 6 << condition;
+        a = 6        && 7;
+
+        a = false     && condition;
+        a = NaN       && console.log("b");
+        a = 0         && console.log("c");
+        a = undefined && 2 * condition;
+        a = null      && condition + 3;
+        a = 2 * 3 - 6 && 4 - condition;
+        a = 10 == 7   && condition / 5;
+        a = !"string" && 6 % condition;
+        a = 0         && 7;
+
+        // don't compress these
+
+        a = condition        && true;
+        a = console.log("a") && 2;
+        a = 4 - condition    && "string";
+        a = 6 << condition   && -4.5;
+
+        a = condition        && false;
+        a = console.log("b") && NaN;
+        a = console.log("c") && 0;
+        a = 2 * condition    && undefined;
+        a = condition + 3    && null;
+
+    }
+    expect: {
+        var a;
+
+        a = condition;
+        a = console.log("a");
+        a = 2 * condition;
+        a = condition + 3;
+        a = 4 - condition;
+        a = condition / 5;
+        a = 6 << condition;
+        a = 7;
+
+        a = false;
+        a = NaN;
+        a = 0;
+        a = void 0;
+        a = null;
+        a = 0;
+        a = false;
+        a = false;
+        a = 0;
+
+        a = condition        && true;
+        a = console.log("a") && 2;
+        a = 4 - condition    && "string";
+        a = 6 << condition   && -4.5;
+
+        a = condition        && false;
+        a = console.log("b") && NaN;
+        a = console.log("c") && 0;
+        a = 2 * condition    && void 0;
+        a = condition + 3    && null;
+    }
+}
+
+or: {
+    options = {
+        evaluate: true
+    }
+    input: {
+        var a;
+        // compress these
+
+        a = true     || condition;
+        a = 1        || console.log("a");
+        a = 2 * 3    || 2 * condition;
+        a = 5 == 5   || condition + 3;
+        a = "string" || 4 - condition;
+        a = 5 + ""   || condition / 5;
+        a = -4.5     || 6 << condition;
+        a = 6        || 7;
+
+        a = false     || condition;
+        a = 0         || console.log("b");
+        a = NaN       || console.log("c");
+        a = undefined || 2 * condition;
+        a = null      || condition + 3;
+        a = 2 * 3 - 6 || 4 - condition;
+        a = 10 == 7   || condition / 5;
+        a = !"string" || 6 % condition;
+        a = null      || 7;
+
+        a = console.log(undefined && condition || null);
+        a = console.log(undefined || condition && null);
+
+        // don't compress these
+
+        a = condition        || true;
+        a = console.log("a") || 2;
+        a = 4 - condition    || "string";
+        a = 6 << condition   || -4.5;
+
+        a = condition        || false;
+        a = console.log("b") || NaN;
+        a = console.log("c") || 0;
+        a = 2 * condition    || undefined;
+        a = condition + 3    || null;
+
+    }
+    expect: {
+        var a;
+
+        a = true;
+        a = 1;
+        a = 6;
+        a = true;
+        a = "string";
+        a = "5";
+        a = -4.5;
+        a = 6;
+
+        a = condition;
+        a = console.log("b");
+        a = console.log("c");
+        a = 2 * condition;
+        a = condition + 3;
+        a = 4 - condition;
+        a = condition / 5;
+        a = 6 % condition;
+        a = 7;
+
+        a = console.log(null);
+        a = console.log(condition && null);
+
+        a = condition        || true;
+        a = console.log("a") || 2;
+        a = 4 - condition    || "string";
+        a = 6 << condition   || -4.5;
+
+        a = condition        || false;
+        a = console.log("b") || NaN;
+        a = console.log("c") || 0;
+        a = 2 * condition    || void 0;
+        a = condition + 3    || null;
+    }
+}
+
+unary_prefix: {
+    options = {
+        evaluate: true
+    }
+    input: {
+        a = !0 && b;
+        a = !0 || b;
+        a = ~1 && b;
+        a = ~1 || b;
+        a = -2 && b;
+        a = -2 || b;
+        a = +3 && b;
+        a = +3 || b;
+    }
+    expect: {
+        a = b;
+        a = !0;
+        a = b;
+        a = -2;
+        a = b;
+        a = -2;
+        a = b;
+        a = 3;
+    }
+}
+
 negative_zero: {
     options = { evaluate: true }
     input: {
diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index c401ac66..2301a92a 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -136,30 +136,30 @@ modified: {
         }
 
         function f2() {
-            var a = 1, b = 2, c = 3;
+            var b = 2, c = 3;
             b = c;
-            console.log(a + b);
-            console.log(b + c);
+            console.log(1 + b);
+            console.log(b + 3);
             console.log(4);
-            console.log(a + b + c);
+            console.log(1 + b + 3);
         }
 
         function f3() {
-            var a = 1, b = 2, c = 3;
+            var b = 2, c = 3;
             b *= c;
-            console.log(a + b);
-            console.log(b + c);
+            console.log(1 + b);
+            console.log(b + 3);
             console.log(4);
-            console.log(a + b + c);
+            console.log(1 + b + 3);
         }
 
         function f4() {
-            var a = 1, b = 2, c = 3;
+            var b = 2, c = 3;
             b = c;
-            console.log(a + b);
+            console.log(1 + b);
             console.log(b + c);
-            console.log(a + c);
-            console.log(a + b + c);
+            console.log(1 + c);
+            console.log(1 + b + c);
         }
 
         function f5(a) {