From db3d83e79532cd48fbd852f7ab1370d0218dfe91 Mon Sep 17 00:00:00 2001
From: Alon Zakai <alonzakai@gmail.com>
Date: Thu, 7 Apr 2016 20:36:53 -0700
Subject: refactor checks in SimplifyLocals

---
 src/passes/SimplifyLocals.cpp | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/passes/SimplifyLocals.cpp b/src/passes/SimplifyLocals.cpp
index cd6cb2ca7..5368701d7 100644
--- a/src/passes/SimplifyLocals.cpp
+++ b/src/passes/SimplifyLocals.cpp
@@ -79,6 +79,7 @@ struct SimplifyLocals : public WalkerPass<FastExecutionWalker<SimplifyLocals>> {
   }
 
   void checkInvalidations(EffectAnalyzer& effects) {
+    // TODO: this is O(bad)
     std::vector<Name> invalidated;
     for (auto& sinkable : sinkables) {
       if (effects.invalidates(sinkable.second.effects)) {
@@ -90,23 +91,29 @@ struct SimplifyLocals : public WalkerPass<FastExecutionWalker<SimplifyLocals>> {
     }
   }
 
-  void walk(Expression*& curr) override {
-    if (!curr) return;
-
+  void checkPre(Expression* curr) {
     EffectAnalyzer effects;
-
     if (effects.checkPre(curr)) {
       checkInvalidations(effects);
     }
+  }
 
-    FastExecutionWalker::walk(curr);
-
-    // TODO: this is O(n^2) in sinkables
-
+  void checkPost(Expression* curr) {
+    EffectAnalyzer effects;
     if (effects.checkPost(curr)) {
       checkInvalidations(effects);
     }
   }
+
+  void walk(Expression*& curr) override {
+    if (!curr) return;
+
+    checkPre(curr);
+
+    FastExecutionWalker::walk(curr);
+
+    checkPost(curr);
+  }
 };
 
 static RegisterPass<SimplifyLocals> registerPass("simplify-locals", "miscellaneous locals-related optimizations");
-- 
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