do not registerize with switches present

3 files changed, 69 insertions, 4 deletions

diff --git a/tools/js-optimizer.js b/tools/js-optimizer.js
index eda85799..2f6b2ff3 100644
--- a/tools/js-optimizer.js
+++ b/tools/js-optimizer.js
@@ -1143,11 +1143,17 @@ function loopOptimizer(ast) {
 }
 
 // Very simple 'registerization', coalescing of variables into a smaller number.
+// We do not optimize when there are switches, so this pass only makes sense with
+// relooping.
+// TODO: Consider how this fits in with the rest of the optimization toolchain. Do
+//       we still need the eliminator? Closure? And in what order? Perhaps just
+//       closure simple?
 function registerize(ast) {
   traverseGeneratedFunctions(ast, function(fun) {
     // Replace all var definitions with assignments; we will add var definitions at the top after we registerize
     // We also mark local variables - i.e., having a var definition
     var localVars = {};
+    var hasSwitch = false; // we cannot optimize variables if there is a switch
     traverse(fun, function(node, type) {
       if (type == 'var') {
         node[1].forEach(function(defined) { localVars[defined[0]] = 1 });
@@ -1167,6 +1173,8 @@ function registerize(ast) {
         } else {
           return emptyNode();
         }
+      } else if (type == 'switch') {
+        hasSwitch = true;
       }
     });
     vacuum(fun);
@@ -1215,8 +1223,10 @@ function registerize(ast) {
       }
     });
     var optimizables = {};
-    for (var possible in possibles) {
-      if (!unoptimizables[possible]) optimizables[possible] = 1;
+    if (!hasSwitch) {
+      for (var possible in possibles) {
+        if (!unoptimizables[possible]) optimizables[possible] = 1;
+      }
     }
     // Go through the function's code, assigning 'registers'.
     // The only tricky bit is to keep variables locked on a register through loops,
diff --git a/tools/test-js-optimizer-regs-output.js b/tools/test-js-optimizer-regs-output.js
index 16d675b8..a5e97f46 100644
--- a/tools/test-js-optimizer-regs-output.js
+++ b/tools/test-js-optimizer-regs-output.js
@@ -197,4 +197,32 @@ function ex() {
     }))();
   }
 }
-// EMSCRIPTEN_GENERATED_FUNCTIONS: ["test", "primes", "atomic", "fcntl_open", "ex"]
+function switchey(x) {
+  var r1, r2, r3, r4, r5, r6, r7, r8;
+  r1 = 5;
+  while (1) {
+    switch (x = f(x, r1)) {
+     case 1:
+      g(r1);
+      r2 = x + 1;
+      x--;
+      break;
+     case 2:
+      g(r1 * 2);
+      r3 = x + 22;
+      r4 = r3 + 5;
+      x -= 20;
+      break;
+     default:
+      r5 = x + 22;
+      r6 = r3 + 5;
+      ch(r5, r6 * r3);
+      throw 99;
+    }
+  }
+  r7 = x + 1;
+  p(r1, r7);
+  r8 = x + 2;
+  pp(r8);
+}
+// EMSCRIPTEN_GENERATED_FUNCTIONS: ["test", "primes", "atomic", "fcntl_open", "ex", "switchey"]
diff --git a/tools/test-js-optimizer-regs.js b/tools/test-js-optimizer-regs.js
index 576e2f8c..2aa95b74 100644
--- a/tools/test-js-optimizer-regs.js
+++ b/tools/test-js-optimizer-regs.js
@@ -203,4 +203,31 @@ function ex() {
     }))();
   }
 }
-// EMSCRIPTEN_GENERATED_FUNCTIONS: ["test", "primes", "atomic", "fcntl_open", "ex"]
+function switchey(x) {
+  var a = 5;
+  while (1) {
+    switch (x = f(x, a)) {
+      case 1:
+        g(a);
+        var b = x+1;
+        x--;
+        break;
+      case 2:
+        g(a*2);
+        var c = x+22;
+        var d = c+5;
+        x -= 20;
+        break;
+      default:
+        var c1 = x+22;
+        var d2 = c+5;
+        ch(c1, d2*c);
+        throw 99;
+    }
+  }
+  var aa = x+1;
+  p(a, aa);
+  var aaa = x+2;
+  pp(aaa);
+}
+// EMSCRIPTEN_GENERATED_FUNCTIONS: ["test", "primes", "atomic", "fcntl_open", "ex", "switchey"]