From ad38f9b80003bfd782e9d0a5bbcca4ebbca3d781 Mon Sep 17 00:00:00 2001
From: Trevor Spiteri <tspiteri@ieee.org>
Date: Tue, 23 Apr 2024 15:49:00 +0200
Subject: [PATCH] unroll first iter of checked_ilog loop to save one
 multiplication

---
 core/src/num/uint_macros.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/core/src/num/uint_macros.rs b/core/src/num/uint_macros.rs
index c13763243f031..a76b84e7e5412 100644
--- a/core/src/num/uint_macros.rs
+++ b/core/src/num/uint_macros.rs
@@ -1093,9 +1093,12 @@ macro_rules! uint_impl {
         pub const fn checked_ilog(self, base: Self) -> Option<u32> {
             if self <= 0 || base <= 1 {
                 None
+            } else if self < base {
+                Some(0)
             } else {
-                let mut n = 0;
-                let mut r = 1;
+                // Since base >= self, n >= 1
+                let mut n = 1;
+                let mut r = base;
 
                 // Optimization for 128 bit wide integers.
                 if Self::BITS == 128 {