improve eliminator

3 files changed, 20 insertions, 3 deletions

diff --git a/tools/eliminator/eliminator-test-output.js b/tools/eliminator/eliminator-test-output.js
index ccbd5e5f..594508d0 100644
--- a/tools/eliminator/eliminator-test-output.js
+++ b/tools/eliminator/eliminator-test-output.js
@@ -97,4 +97,12 @@ var anon = (function(x) {
 function r($0) {
   HEAP[$0 + 7] = 107;
 }
-// EMSCRIPTEN_GENERATED_FUNCTIONS: ["f", "g", "h", "py", "r"]
+function t() {
+  if ($10 < $11) {
+    __label__ = 3;
+  }
+  if (!($12 < $13)) {
+    __label__ = 4;
+  }
+}
+// EMSCRIPTEN_GENERATED_FUNCTIONS: ["f", "g", "h", "py", "r", "t"]
diff --git a/tools/eliminator/eliminator-test.js b/tools/eliminator/eliminator-test.js
index 2443d707..02ac0c08 100644
--- a/tools/eliminator/eliminator-test.js
+++ b/tools/eliminator/eliminator-test.js
@@ -108,5 +108,11 @@ var anon = function(x) {
 function r($0) {
   HEAP[$0 + 5 + 2] = 99+5+2+1;
 }
-// EMSCRIPTEN_GENERATED_FUNCTIONS: ["f", "g", "h", "py", "r"]
+function t() {
+  var $cmp2=($10) < ($11);
+  if ($cmp2) { __label__ = 3; }
+  var $cmp3=($12) < ($13);
+  if (!($cmp3)) { __label__ = 4; }
+}
+// EMSCRIPTEN_GENERATED_FUNCTIONS: ["f", "g", "h", "py", "r", "t"]
 
diff --git a/tools/eliminator/eliminator.coffee b/tools/eliminator/eliminator.coffee
index 62e7ef82..8b99338a 100644
--- a/tools/eliminator/eliminator.coffee
+++ b/tools/eliminator/eliminator.coffee
@@ -42,6 +42,7 @@ NODES_WITHOUT_SIDE_EFFECTS =
   string: true
   binary: true
   sub: true
+  'unary-prefix': true # ++x can have side effects, but we never have that in generated code
 
 # Nodes which may break control flow. Moving a variable beyond them may have
 # side effects.
@@ -148,7 +149,7 @@ class Eliminator
         varName = node[1]
         if @useCount.hasOwnProperty varName then @useCount[varName]++
         else @isSingleDef[varName] = false
-      else if type in ['assign', 'unary-prefix', 'unary-postfix']
+      else if type in ['assign']
         varName = node[2][1]
         if @isSingleDef[varName] then @isSingleDef[varName] = false
       return undefined
@@ -374,6 +375,8 @@ main = ->
 
   ast = uglify.parser.parse src
 
+  #process.stderr.write(JSON.stringify(ast) + '\n')
+
   # Run on all functions.
   traverse ast, (node, type) ->
     if type in ['defun', 'function'] and isGenerated node[1]