Code pushing (#807)

Push code forward, potentially letting it not execute

1 files changed, 16 insertions, 0 deletions

diff --git a/src/ast_utils.h b/src/ast_utils.h
index 9dfacb972..f10fb40eb 100644
--- a/src/ast_utils.h
+++ b/src/ast_utils.h
@@ -102,6 +102,11 @@ struct DirectCallGraphAnalyzer : public PostWalker<DirectCallGraphAnalyzer, Visi
 struct EffectAnalyzer : public PostWalker<EffectAnalyzer, Visitor<EffectAnalyzer>> {
   EffectAnalyzer() {}
   EffectAnalyzer(Expression *ast) {
+    analyze(ast);
+  }
+
+  void analyze(Expression *ast) {
+    breakNames.clear();
     walk(ast);
     // if we are left with breaks, they are external
     if (breakNames.size() > 0) branches = true;
@@ -151,6 +156,17 @@ struct EffectAnalyzer : public PostWalker<EffectAnalyzer, Visitor<EffectAnalyzer
     return false;
   }
 
+  void mergeIn(EffectAnalyzer& other) {
+    branches = branches || other.branches;
+    calls = calls || other.calls;
+    readsMemory = readsMemory || other.readsMemory;
+    writesMemory = writesMemory || other.writesMemory;
+    for (auto i : other.localsRead) localsRead.insert(i);
+    for (auto i : other.localsWritten) localsWritten.insert(i);
+    for (auto i : other.globalsRead) globalsRead.insert(i);
+    for (auto i : other.globalsWritten) globalsWritten.insert(i);
+  }
+
   // the checks above happen after the node's children were processed, in the order of execution
   // we must also check for control flow that happens before the children, i.e., loops
   bool checkPre(Expression* curr) {