From 352095a3b8ebedeb3810f5ed6a609cfc313e3fd2 Mon Sep 17 00:00:00 2001
From: Devyn Cairns <devyn.cairns@gmail.com>
Date: Wed, 12 Jun 2024 02:47:01 -0700
Subject: [PATCH] trying a little bit of preemptive optimization

---
 crates/nu-engine/src/eval_ir.rs | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/crates/nu-engine/src/eval_ir.rs b/crates/nu-engine/src/eval_ir.rs
index 45fa12e375..f6bfbcb4d9 100644
--- a/crates/nu-engine/src/eval_ir.rs
+++ b/crates/nu-engine/src/eval_ir.rs
@@ -23,17 +23,18 @@ pub fn eval_ir_block<D: DebugContext>(
         //
         // Keep in mind that there is some code generated for each variant; at least at the moment
         // it doesn't seem like LLVM is able to optimize this away
-        let result = match ir_block.register_count {
-            0..=4 => {
+        //
+        // This is organized like a tree to try to make sure we do the fewest number of branches
+        let result = if ir_block.register_count <= 8 {
+            if ir_block.register_count <= 4 {
                 eval_ir_block_static::<D, 4>(engine_state, stack, &block_span, ir_block, input)
-            }
-            5..=8 => {
+            } else {
                 eval_ir_block_static::<D, 8>(engine_state, stack, &block_span, ir_block, input)
             }
-            9..=16 => {
-                eval_ir_block_static::<D, 16>(engine_state, stack, &block_span, ir_block, input)
-            }
-            _ => eval_ir_block_dynamic::<D>(engine_state, stack, &block_span, ir_block, input),
+        } else if ir_block.register_count <= 16 {
+            eval_ir_block_static::<D, 16>(engine_state, stack, &block_span, ir_block, input)
+        } else {
+            eval_ir_block_dynamic::<D>(engine_state, stack, &block_span, ir_block, input)
         };
 
         D::leave_block(engine_state, block);