From be580c66645cdea13c8e8b3b77f12ef3a52e5f2e Mon Sep 17 00:00:00 2001
From: Alon Zakai <azakai@google.com>
Date: Wed, 28 Jul 2021 09:11:43 -0700
Subject: [Wasm GC] DeadArgumentElimination: Update tees after refining param
 types (#4031)

---
 src/passes/DeadArgumentElimination.cpp | 15 +++++++++++++--
 src/passes/LocalSubtyping.cpp          |  3 ++-
 2 files changed, 15 insertions(+), 3 deletions(-)

(limited to 'src')

diff --git a/src/passes/DeadArgumentElimination.cpp b/src/passes/DeadArgumentElimination.cpp
index 7ba1be9f8..9d8fa5b0d 100644
--- a/src/passes/DeadArgumentElimination.cpp
+++ b/src/passes/DeadArgumentElimination.cpp
@@ -588,7 +588,8 @@ private:
     // In terms of parameters, we can do this. However, we must also check
     // local operations in the body, as if the parameter is reused and written
     // to, then those types must be taken into account as well.
-    for (auto* set : FindAll<LocalSet>(func->body).list) {
+    FindAll<LocalSet> sets(func->body);
+    for (auto* set : sets.list) {
       auto index = set->index;
       if (func->isParam(index) &&
           !Type::isSubType(set->value->type, newParamTypes[index])) {
@@ -602,7 +603,7 @@ private:
       return;
     }
 
-    // We can do this! Update the types, including the types of gets.
+    // We can do this! Update the types, including the types of gets and tees.
     func->setParams(newParams);
     for (auto* get : FindAll<LocalGet>(func->body).list) {
       auto index = get->index;
@@ -610,6 +611,16 @@ private:
         get->type = func->getLocalType(index);
       }
     }
+    for (auto* set : sets.list) {
+      auto index = set->index;
+      if (func->isParam(index) && set->isTee()) {
+        set->type = func->getLocalType(index);
+        set->finalize();
+      }
+    }
+
+    // Propagate the new get and set types outwards.
+    ReFinalize().walkFunctionInModule(func, module);
   }
 
   // See if the types returned from a function allow us to define a more refined
diff --git a/src/passes/LocalSubtyping.cpp b/src/passes/LocalSubtyping.cpp
index 9c6da1131..472463f44 100644
--- a/src/passes/LocalSubtyping.cpp
+++ b/src/passes/LocalSubtyping.cpp
@@ -134,8 +134,9 @@ struct LocalSubtyping : public WalkerPass<PostWalker<LocalSubtyping>> {
           // NB: These tee updates will not be needed if the type of tees
           //     becomes that of their value, in the spec.
           for (auto* set : setsForLocal[i]) {
-            if (set->isTee() && set->type != Type::unreachable) {
+            if (set->isTee()) {
               set->type = newType;
+              set->finalize();
             }
           }
         }
-- 
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