Optimize Try in Vacuum (#2644)

If try's body does not throw, the whole try-catch can be replaced with
the try body.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/passes/Vacuum.cpp b/src/passes/Vacuum.cpp
index f0bdd7722..54707fddc 100644
--- a/src/passes/Vacuum.cpp
+++ b/src/passes/Vacuum.cpp
@@ -414,6 +414,15 @@ struct Vacuum : public WalkerPass<ExpressionStackWalker<Vacuum>> {
     }
   }
 
+  void visitTry(Try* curr) {
+    // If try's body does not throw, the whole try-catch can be replaced with
+    // the try's body.
+    if (!EffectAnalyzer(getPassOptions(), getModule()->features, curr->body)
+           .throws) {
+      replaceCurrent(curr->body);
+    }
+  }
+
   void visitFunction(Function* curr) {
     auto* optimized =
       optimize(curr->body, curr->sig.results != Type::none, true);