From 5641ae71b86349621071065dd416c5e9919d0fc3 Mon Sep 17 00:00:00 2001
From: Fabian Boehm <FHomborg@gmail.com>
Date: Tue, 27 Feb 2024 18:58:32 +0100
Subject: [PATCH] ast: Box a large enum variant

IfStatement is 680 bytes, much larger than the other
variants (SwitchStatement is next at 232). An enum is as large as its
largest variant, so this saves a bunch, especially since
DecoratedStatement is much more likely than IfStatement.

This will speed up the no-execute benchmark by 1.07x.
---
 src/ast.rs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/ast.rs b/src/ast.rs
index a782ece6c..ff2f8cc7e 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -2001,7 +2001,8 @@ pub enum StatementVariant {
     None,
     NotStatement(NotStatement),
     BlockStatement(BlockStatement),
-    IfStatement(IfStatement),
+    // IfStatement is much larger than the rest, so we box it.
+    IfStatement(Box<IfStatement>),
     SwitchStatement(SwitchStatement),
     DecoratedStatement(DecoratedStatement),
 }
@@ -2081,7 +2082,7 @@ fn embedded_node(&self) -> &dyn NodeMut {
             StatementVariant::None => panic!("cannot visit null statement"),
             StatementVariant::NotStatement(node) => node,
             StatementVariant::BlockStatement(node) => node,
-            StatementVariant::IfStatement(node) => node,
+            StatementVariant::IfStatement(node) => &**node,
             StatementVariant::SwitchStatement(node) => node,
             StatementVariant::DecoratedStatement(node) => node,
         }
@@ -3612,7 +3613,7 @@ fn new_decorated_statement(slf: &mut Populator<'_>) -> Box<StatementVariant> {
             }
             ParseKeyword::kw_if => {
                 let embedded = self.allocate_visit::<IfStatement>();
-                Box::new(StatementVariant::IfStatement(*embedded))
+                Box::new(StatementVariant::IfStatement(embedded))
             }
             ParseKeyword::kw_switch => {
                 let embedded = self.allocate_visit::<SwitchStatement>();