commit 678c6fad94c5a0631b9ecd72f1f963c77096e5f9
author Federico Stra <stra.federico@gmail.com> Sun Sep 17 14:53:16 2023 +0200
committer Federico Stra <stra.federico@gmail.com> Fri Sep 22 16:03:14 2023 +0200
tree e2fd56fa11ff7be07a040d50a0407dc37ba53d85
parent 03c199af8e0f10c4fe4ead8e97e65286bef86e7d

checked_ilog: improve performance

library/core/src/num/int_macros.rs

diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs
index 1f43520..aed6a34 100644
--- a/library/core/src/num/int_macros.rs
+++ b/library/core/src/num/int_macros.rs
@@ -2477,18 +2477,18 @@
                 None
             } else {
                 let mut n = 0;
-                let mut r = self;
+                let mut r = 1;
 
                 // Optimization for 128 bit wide integers.
                 if Self::BITS == 128 {
                     let b = Self::ilog2(self) / (Self::ilog2(base) + 1);
                     n += b;
-                    r /= base.pow(b as u32);
+                    r *= base.pow(b);
                 }
 
-                while r >= base {
-                    r /= base;
+                while r <= self / base {
                     n += 1;
+                    r *= base;
                 }
                 Some(n)
             }

library/core/src/num/uint_macros.rs

diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
index 23ca378..d7f2ad8 100644
--- a/library/core/src/num/uint_macros.rs
+++ b/library/core/src/num/uint_macros.rs
@@ -810,18 +810,18 @@
                 None
             } else {
                 let mut n = 0;
-                let mut r = self;
+                let mut r = 1;
 
                 // Optimization for 128 bit wide integers.
                 if Self::BITS == 128 {
                     let b = Self::ilog2(self) / (Self::ilog2(base) + 1);
                     n += b;
-                    r /= base.pow(b as u32);
+                    r *= base.pow(b);
                 }
 
-                while r >= base {
-                    r /= base;
+                while r <= self / base {
                     n += 1;
+                    r *= base;
                 }
                 Some(n)
             }