From a3c339c259d0dafc87fac565fac308e9699726f9 Mon Sep 17 00:00:00 2001
From: Alon Zakai <alonzakai@gmail.com>
Date: Sat, 11 Jun 2016 17:31:12 -0700
Subject: fix br_if with value optimization in remove-unused-brs

---
 src/passes/RemoveUnusedBrs.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'src')

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index ffdba0768..3f909c32e 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -128,6 +128,13 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs, Visitor<R
       // if without an else. try to reduce   if (condition) br  =>  br_if (condition)
       Break* br = curr->ifTrue->dynCast<Break>();
       if (br && !br->condition) { // TODO: if there is a condition, join them
+        // if the br has a value, then if => br_if means we always execute the value, and also the order is value,condition vs condition,value
+        if (br->value) {
+          EffectAnalyzer value(br->value);
+          if (value.hasSideEffects()) return;
+          EffectAnalyzer condition(curr->condition);
+          if (condition.invalidates(value)) return;
+        }
         br->condition = curr->condition;
         replaceCurrent(br);
         anotherCycle = true;
-- 
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