eliminate X=X which can happen due to elimination

3 files changed, 25 insertions, 1 deletions

diff --git a/tools/eliminator/asm-eliminator-test-output.js b/tools/eliminator/asm-eliminator-test-output.js
index 7a8baef2..e1bc83bf 100644
--- a/tools/eliminator/asm-eliminator-test-output.js
+++ b/tools/eliminator/asm-eliminator-test-output.js
@@ -810,4 +810,13 @@ function cute($this, $outImage) {
  }
  return 0;
 }
+function selfAssign() {
+ var i1 = 0;
+ i1 = HEAP32[2] | 0;
+ HEAP32[2] = i1 + 1;
+ if (waka) {
+  return 0;
+ }
+ return i1 & 16384 | 0;
+}
 
diff --git a/tools/eliminator/asm-eliminator-test.js b/tools/eliminator/asm-eliminator-test.js
index ad1ed05e..8886d54a 100644
--- a/tools/eliminator/asm-eliminator-test.js
+++ b/tools/eliminator/asm-eliminator-test.js
@@ -1027,5 +1027,15 @@ function cute($this, $outImage) {
  }
  return 0;
 }
-// EMSCRIPTEN_GENERATED_FUNCTIONS: ["asm", "__Z11printResultPiS_j", "_segment_holding", "__ZN5identC2EiPKcPci", "_vec2Length", "exc", "label", "confuusion", "tempDouble", "_org_apache_harmony_luni_util_NumberConverter_freeFormat__", "__ZN23b2EdgeAndPolygonContact8EvaluateEP10b2ManifoldRK11b2TransformS4_", "_java_nio_charset_Charset_forNameInternal___java_lang_String", "looop2", "looop3", "looop4", "looop5", "looop6", "looop7", "looop8", "multiloop", "multiloop2", "tempDouble2", "watIf", "select2", "binary", "cute"]
+function selfAssign() {
+ var i1 = 0;
+ i1 = HEAP32[2] | 0;
+ HEAP32[2] = i1 + 1;
+ if (waka) {
+  return (STACKTOP = STACKTOP, 0);
+ }
+ STACKTOP = STACKTOP;
+ return i1 & 16384 | 0;
+}
+// EMSCRIPTEN_GENERATED_FUNCTIONS: ["asm", "__Z11printResultPiS_j", "_segment_holding", "__ZN5identC2EiPKcPci", "_vec2Length", "exc", "label", "confuusion", "tempDouble", "_org_apache_harmony_luni_util_NumberConverter_freeFormat__", "__ZN23b2EdgeAndPolygonContact8EvaluateEP10b2ManifoldRK11b2TransformS4_", "_java_nio_charset_Charset_forNameInternal___java_lang_String", "looop2", "looop3", "looop4", "looop5", "looop6", "looop7", "looop8", "multiloop", "multiloop2", "tempDouble2", "watIf", "select2", "binary", "cute", "selfAssign"]
 
diff --git a/tools/js-optimizer.js b/tools/js-optimizer.js
index 129c493f..49bc9d11 100644
--- a/tools/js-optimizer.js
+++ b/tools/js-optimizer.js
@@ -292,6 +292,8 @@ function removeEmptySubNodes(node) {
     node[3] = filterEmptyNodes(node[3]);
   } else if (node[0] === 'block' && node[1]) {
     node[1] = filterEmptyNodes(node[1]);
+  } else if (node[0] === 'seq' && isEmptyNode(node[1])) {
+    return node[2];
   }
 /*
   var stats = getStatements(node);
@@ -3912,6 +3914,9 @@ function eliminate(ast, memSafe) {
           node[0] = 'toplevel';
           node[1] = [];
         }
+      } else if (type === 'assign' && node[1] === true && node[2][0] === 'name' && node[3][0] === 'name' && node[2][1] === node[3][1]) {
+        // elimination led to X = X, which we can just remove
+        return emptyNode();
       }
     }, function(node, type) {
       // post