From 5de55af88eaac818f86eaaec3f686eaede01397e Mon Sep 17 00:00:00 2001
From: Alon Zakai <alonzakai@gmail.com>
Date: Tue, 2 May 2017 13:46:53 -0700
Subject: improve dce to handle more cases of nested unreachable code (#989)

* improve dce to handle more cases of nested unreachable code, in particular, when the child is unreachable in type but not an actual Unreachable node, e.g. if it's a br. in that case, we just need to verify that the br is not to us where we are a block or loop

* handle unreachable switch conditions in dce

* handle dce of br condition which is unreachable, and host arguments

* handle dce of block i32 etc. which is actually unreachable
---
 src/wasm/wasm.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'src/wasm/wasm.cpp')

diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index a983fc943..36eff681f 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -409,7 +409,12 @@ void Host::finalize() {
       break;
     }
     case GrowMemory: {
-      type = i32;
+      // if the single operand is not reachable, so are we
+      if (operands[0]->type == unreachable) {
+        type = unreachable;
+      } else {
+        type = i32;
+      }
       break;
     }
     default: abort();
-- 
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