From 9dee59071a405b137442ac13f5304e52595d2f32 Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Wed, 15 Jul 2020 22:39:39 +0800
Subject: [PATCH 01/11] Rearrange the pipeline of `pow` to gain efficiency
The check of the `exp` parameter seems useless if we execute the while-loop more than once.
The original implementation of `pow` function using one more comparison if the `exp==0` and may break the pipeline of the cpu, which may generate a slower code.
The performance gap between the old and the new implementation may be small, but IMO, at least the newer one looks more beautiful.
---
bench prog:
```
#![feature(test)]
extern crate test;
#[macro_export]macro_rules! timing{
($a:expr)=>{let time=std::time::Instant::now();{$a;}print!("{:?} ",time.elapsed())};
($a:expr,$b:literal)=>{let time=std::time::Instant::now();let mut a=0;for _ in 0..$b{a^=$a;}print!("{:?} {} ",time.elapsed(),a)}
}
#[inline]
pub fn pow_rust(x:i64, mut exp: u32) -> i64 {
let mut base = x;
let mut acc = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = acc * base;
}
exp /= 2;
base = base * base;
}
if exp == 1 {
acc = acc * base;
}
acc
}
#[inline]
pub fn pow_new(x:i64, mut exp: u32) -> i64 {
if exp==0{
1
}else{
let mut base = x;
let mut acc = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = acc * base;
}
exp >>= 1;
base = base * base;
}
acc * base
}
}
fn main(){
let a=2i64;
let b=1_u32;
println!();
timing!(test::black_box(a).pow(test::black_box(b)),100000000);
timing!(pow_new(test::black_box(a),test::black_box(b)),100000000);
timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000);
println!();
timing!(test::black_box(a).pow(test::black_box(b)),100000000);
timing!(pow_new(test::black_box(a),test::black_box(b)),100000000);
timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000);
println!();
timing!(test::black_box(a).pow(test::black_box(b)),100000000);
timing!(pow_new(test::black_box(a),test::black_box(b)),100000000);
timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000);
println!();
timing!(test::black_box(a).pow(test::black_box(b)),100000000);
timing!(pow_new(test::black_box(a),test::black_box(b)),100000000);
timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000);
println!();
timing!(test::black_box(a).pow(test::black_box(b)),100000000);
timing!(pow_new(test::black_box(a),test::black_box(b)),100000000);
timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000);
println!();
timing!(test::black_box(a).pow(test::black_box(b)),100000000);
timing!(pow_new(test::black_box(a),test::black_box(b)),100000000);
timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000);
println!();
timing!(test::black_box(a).pow(test::black_box(b)),100000000);
timing!(pow_new(test::black_box(a),test::black_box(b)),100000000);
timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000);
println!();
timing!(test::black_box(a).pow(test::black_box(b)),100000000);
timing!(pow_new(test::black_box(a),test::black_box(b)),100000000);
timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000);
println!();
}
```
bench in my laptop:
```
neutron@Neutron:/me/rust$ rc commit.rs
rustc commit.rs && ./commit
3.978419716s 0 4.079765171s 0 3.964630622s 0
3.997127013s 0 4.260304804s 0 3.997638211s 0
3.963195544s 0 4.11657718s 0 4.176054164s 0
3.830128579s 0 3.980396122s 0 3.937258567s 0
3.986055948s 0 4.127804162s 0 4.018943411s 0
4.185568857s 0 4.217512517s 0 3.98313603s 0
3.863018225s 0 4.030447988s 0 3.694878237s 0
4.206987927s 0 4.137608047s 0 4.115564664s 0
neutron@Neutron:/me/rust$ rc commit.rs -O
rustc commit.rs -O && ./commit
162.111993ms 0 165.107125ms 0 166.26924ms 0
175.20479ms 0 205.062565ms 0 176.278791ms 0
174.408975ms 0 166.526899ms 0 201.857604ms 0
146.190062ms 0 168.592821ms 0 154.61411ms 0
199.678912ms 0 168.411598ms 0 162.129996ms 0
147.420765ms 0 209.759326ms 0 154.807907ms 0
165.507134ms 0 188.476239ms 0 157.351524ms 0
121.320123ms 0 126.401229ms 0 114.86428ms 0
```
---
src/libcore/num/mod.rs | 88 +++++++++++++++++++++---------------------
1 file changed, 43 insertions(+), 45 deletions(-)
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index f4a1afd436adb..dd9fd04d41294 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -1103,6 +1103,9 @@ $EndFeature, "
without modifying the original"]
#[inline]
pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
+ if exp == 0 {
+ return Some(1);
+ }
let mut base = self;
let mut acc: Self = 1;
@@ -1113,15 +1116,11 @@ $EndFeature, "
exp /= 2;
base = try_opt!(base.checked_mul(base));
}
-
+ // since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
- if exp == 1 {
- acc = try_opt!(acc.checked_mul(base));
- }
-
- Some(acc)
+ Some(try_opt!(acc.checked_mul(base)))
}
}
@@ -1631,6 +1630,9 @@ $EndFeature, "
without modifying the original"]
#[inline]
pub const fn wrapping_pow(self, mut exp: u32) -> Self {
+ if exp == 0 {
+ return 1;
+ }
let mut base = self;
let mut acc: Self = 1;
@@ -1641,15 +1643,12 @@ $EndFeature, "
exp /= 2;
base = base.wrapping_mul(base);
}
-
+
+ // since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
- if exp == 1 {
- acc = acc.wrapping_mul(base);
- }
-
- acc
+ acc.wrapping_mul(base);
}
}
@@ -1999,6 +1998,9 @@ $EndFeature, "
without modifying the original"]
#[inline]
pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
+ if exp == 0 {
+ return (1,false);
+ }
let mut base = self;
let mut acc: Self = 1;
let mut overflown = false;
@@ -2016,17 +2018,14 @@ $EndFeature, "
base = r.0;
overflown |= r.1;
}
-
+
+ // since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
- if exp == 1 {
- r = acc.overflowing_mul(base);
- acc = r.0;
- overflown |= r.1;
- }
-
- (acc, overflown)
+ r = acc.overflowing_mul(base);
+ r.1 |= overflown;
+ r
}
}
@@ -2050,6 +2049,9 @@ $EndFeature, "
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn pow(self, mut exp: u32) -> Self {
+ if exp == 0 {
+ return 1;
+ }
let mut base = self;
let mut acc = 1;
@@ -2061,14 +2063,11 @@ $EndFeature, "
base = base * base;
}
+ // since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
- if exp == 1 {
- acc = acc * base;
- }
-
- acc
+ acc * base
}
}
@@ -3306,6 +3305,9 @@ assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);", $EndFeature, "
without modifying the original"]
#[inline]
pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
+ if exp == 0 {
+ return Some(1);
+ }
let mut base = self;
let mut acc: Self = 1;
@@ -3317,14 +3319,12 @@ assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);", $EndFeature, "
base = try_opt!(base.checked_mul(base));
}
+ // since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
- if exp == 1 {
- acc = try_opt!(acc.checked_mul(base));
- }
- Some(acc)
+ Some(try_opt!(acc.checked_mul(base)))
}
}
@@ -3715,6 +3715,9 @@ assert_eq!(3u8.wrapping_pow(6), 217);", $EndFeature, "
without modifying the original"]
#[inline]
pub const fn wrapping_pow(self, mut exp: u32) -> Self {
+ if exp == 0 {
+ return 1;
+ }
let mut base = self;
let mut acc: Self = 1;
@@ -3726,14 +3729,11 @@ assert_eq!(3u8.wrapping_pow(6), 217);", $EndFeature, "
base = base.wrapping_mul(base);
}
+ // since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
- if exp == 1 {
- acc = acc.wrapping_mul(base);
- }
-
- acc
+ acc.wrapping_mul(base)
}
}
@@ -4058,16 +4058,14 @@ assert_eq!(3u8.overflowing_pow(6), (217, true));", $EndFeature, "
overflown |= r.1;
}
+ // since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
- if exp == 1 {
- r = acc.overflowing_mul(base);
- acc = r.0;
- overflown |= r.1;
- }
+ r = acc.overflowing_mul(base);
+ r.1 |= overflown;
- (acc, overflown)
+ r
}
}
@@ -4088,6 +4086,9 @@ Basic usage:
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn pow(self, mut exp: u32) -> Self {
+ if exp == 0 {
+ return 1;
+ }
let mut base = self;
let mut acc = 1;
@@ -4099,14 +4100,11 @@ Basic usage:
base = base * base;
}
+ // since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
- if exp == 1 {
- acc = acc * base;
- }
-
- acc
+ acc * base
}
}
From ebafab96fce602b45b81a3c5e5acc5af9b7dec3f Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Thu, 16 Jul 2020 09:25:01 +0800
Subject: [PATCH 02/11] delete an unnecessary semicolon...
Sorry for the typo.
---
src/libcore/num/mod.rs | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index dd9fd04d41294..7f89af944ddd1 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -1648,7 +1648,7 @@ $EndFeature, "
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
- acc.wrapping_mul(base);
+ acc.wrapping_mul(base)
}
}
From 020c0b5cb3e92b232adaf60cd130a443e0f12f43 Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Thu, 16 Jul 2020 09:54:48 +0800
Subject: [PATCH 03/11] delete trailing whitespace
Sorry, too..
---
src/libcore/num/mod.rs | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 7f89af944ddd1..7408b2c31b18f 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -1643,7 +1643,7 @@ $EndFeature, "
exp /= 2;
base = base.wrapping_mul(base);
}
-
+
// since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
@@ -2018,7 +2018,7 @@ $EndFeature, "
base = r.0;
overflown |= r.1;
}
-
+
// since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
From 8f58ce41f1c33089c3746ff3941994042dfb51d5 Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Thu, 16 Jul 2020 14:30:07 +0800
Subject: [PATCH 04/11] Sorry for the missing...
I checked all the implementations, and finally found that there is one function that does not check whether `exp == 0`
---
src/libcore/num/mod.rs | 3 +++
1 file changed, 3 insertions(+)
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 7408b2c31b18f..c576465c622fe 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -4040,6 +4040,9 @@ assert_eq!(3u8.overflowing_pow(6), (217, true));", $EndFeature, "
without modifying the original"]
#[inline]
pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
+ if exp == 0{
+ return (1,false);
+ }
let mut base = self;
let mut acc: Self = 1;
let mut overflown = false;
From f3d476b16a9ec9c1471b0eded0bba4ece458d118 Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Thu, 16 Jul 2020 14:58:20 +0800
Subject: [PATCH 05/11] add extra tests
---
src/libcore/tests/num/int_macros.rs | 31 +++++++++++++++++++++++++++--
1 file changed, 29 insertions(+), 2 deletions(-)
diff --git a/src/libcore/tests/num/int_macros.rs b/src/libcore/tests/num/int_macros.rs
index 8396a0dd62db9..7bdaf8364dd4e 100644
--- a/src/libcore/tests/num/int_macros.rs
+++ b/src/libcore/tests/num/int_macros.rs
@@ -252,15 +252,42 @@ macro_rules! int_module {
assert_eq!($T::from_str_radix("-9", 2).ok(), None::<$T>);
}
+
#[test]
fn test_pow() {
let mut r = 2 as $T;
-
assert_eq!(r.pow(2), 4 as $T);
assert_eq!(r.pow(0), 1 as $T);
+ assert_eq!(r.wrapping_pow(2), 4 as $T);
+ assert_eq!(r.wrapping_pow(0), 1 as $T);
+ assert_eq!(r.checked_pow(2), Some(4 as $T));
+ assert_eq!(r.checked_pow(0), Some(1 as $T));
+ assert_eq!(r.overflowing_pow(2), (4 as $T,false));
+ assert_eq!(r.overflowing_pow(0), (1 as $T,false));
+ assert_eq!(r.saturating_pow(2), 4 as $T);
+ assert_eq!(r.saturating_pow(0), 1 as $T);
+
+ r = MAX;
+ // use `^` to represent .pow() with no overflow.
+ // if itest::MAX == 2^j-1, then itest is a `j` bit int,
+ // so that `itest::MAX*itest::MAX == 2^(2*j)-2^(j+1)+1`,
+ // thussaturating_pow the overflowing result is exactly 1.
+ assert_eq!(r.wrapping_pow(2), 1 as $T);
+ assert_eq!(r.checked_pow(2), None);
+ assert_eq!(r.overflowing_pow(2), (1 as $T,true));
+ assert_eq!(r.saturating_pow(2), MAX);
+ //test for negative exponent.
r = -2 as $T;
- assert_eq!(r.pow(2), 4 as $T);
assert_eq!(r.pow(3), -8 as $T);
+ assert_eq!(r.pow(0), 1 as $T);
+ assert_eq!(r.wrapping_pow(3), -8 as $T);
+ assert_eq!(r.wrapping_pow(0), 1 as $T);
+ assert_eq!(r.checked_pow(3), Some(-8) as $T);
+ assert_eq!(r.checked_pow(0), Some(1) as $T);
+ assert_eq!(r.overflowing_pow(3), (-8 as $T,false));
+ assert_eq!(r.overflowing_pow(0), (1 as $T,false));
+ assert_eq!(r.saturating_pow(3), -8 as $T);
+ assert_eq!(r.saturating_pow(0), 1 as $T);
}
}
};
From 87958456a14fdacb2f4027522b0d6c06ca6da284 Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Thu, 16 Jul 2020 14:59:38 +0800
Subject: [PATCH 06/11] add extra tests.
finished adding the extra tests to prevent further typo
---
src/libcore/tests/num/uint_macros.rs | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/src/libcore/tests/num/uint_macros.rs b/src/libcore/tests/num/uint_macros.rs
index 8f1ca8e6fac2c..530a94f5723d7 100644
--- a/src/libcore/tests/num/uint_macros.rs
+++ b/src/libcore/tests/num/uint_macros.rs
@@ -184,6 +184,31 @@ macro_rules! uint_module {
assert_eq!($T::from_str_radix("Z", 10).ok(), None::<$T>);
assert_eq!($T::from_str_radix("_", 2).ok(), None::<$T>);
}
+
+ #[test]
+ fn test_pow() {
+ let mut r = 2 as $T;
+ assert_eq!(r.pow(2), 4 as $T);
+ assert_eq!(r.pow(0), 1 as $T);
+ assert_eq!(r.wrapping_pow(2), 4 as $T);
+ assert_eq!(r.wrapping_pow(0), 1 as $T);
+ assert_eq!(r.checked_pow(2), Some(4 as $T));
+ assert_eq!(r.checked_pow(0), Some(1 as $T));
+ assert_eq!(r.overflowing_pow(2), (4 as $T,false));
+ assert_eq!(r.overflowing_pow(0), (1 as $T,false));
+ assert_eq!(r.saturating_pow(2), 4 as $T);
+ assert_eq!(r.saturating_pow(0), 1 as $T);
+
+ r = MAX;
+ // use `^` to represent .pow() with no overflow.
+ // if itest::MAX == 2^j-1, then itest is a `j` bit int,
+ // so that `itest::MAX*itest::MAX == 2^(2*j)-2^(j+1)+1`,
+ // thussaturating_pow the overflowing result is exactly 1.
+ assert_eq!(r.wrapping_pow(2), 1 as $T);
+ assert_eq!(r.checked_pow(2), None);
+ assert_eq!(r.overflowing_pow(2), (1 as $T,true));
+ assert_eq!(r.saturating_pow(2), MAX);
+ }
}
};
}
From 319db3089b45ba0fef385d78252082f2d0f8d105 Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Thu, 16 Jul 2020 15:06:30 +0800
Subject: [PATCH 07/11] add pow(2) to negative exp
---
src/libcore/tests/num/int_macros.rs | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/src/libcore/tests/num/int_macros.rs b/src/libcore/tests/num/int_macros.rs
index 7bdaf8364dd4e..3293a6a8ef894 100644
--- a/src/libcore/tests/num/int_macros.rs
+++ b/src/libcore/tests/num/int_macros.rs
@@ -278,14 +278,19 @@ macro_rules! int_module {
assert_eq!(r.saturating_pow(2), MAX);
//test for negative exponent.
r = -2 as $T;
+ assert_eq!(r.pow(2), 4 as $T);
assert_eq!(r.pow(3), -8 as $T);
assert_eq!(r.pow(0), 1 as $T);
+ assert_eq!(r.wrapping_pow(2), 4 as $T);
assert_eq!(r.wrapping_pow(3), -8 as $T);
assert_eq!(r.wrapping_pow(0), 1 as $T);
- assert_eq!(r.checked_pow(3), Some(-8) as $T);
- assert_eq!(r.checked_pow(0), Some(1) as $T);
+ assert_eq!(r.checked_pow(2), Some(4 as $T));
+ assert_eq!(r.checked_pow(3), Some(-8 as $T));
+ assert_eq!(r.checked_pow(0), Some(1 as $T));
+ assert_eq!(r.overflowing_pow(2), (4 as $T,false));
assert_eq!(r.overflowing_pow(3), (-8 as $T,false));
assert_eq!(r.overflowing_pow(0), (1 as $T,false));
+ assert_eq!(r.saturating_pow(2), 4 as $T);
assert_eq!(r.saturating_pow(3), -8 as $T);
assert_eq!(r.saturating_pow(0), 1 as $T);
}
From e2f3e3c8072c69db566eca24c04233886d4c2a02 Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Thu, 16 Jul 2020 15:19:48 +0800
Subject: [PATCH 08/11] add whitespace.
---
src/libcore/tests/num/uint_macros.rs | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/src/libcore/tests/num/uint_macros.rs b/src/libcore/tests/num/uint_macros.rs
index 530a94f5723d7..b84a8a7d9f88b 100644
--- a/src/libcore/tests/num/uint_macros.rs
+++ b/src/libcore/tests/num/uint_macros.rs
@@ -194,8 +194,8 @@ macro_rules! uint_module {
assert_eq!(r.wrapping_pow(0), 1 as $T);
assert_eq!(r.checked_pow(2), Some(4 as $T));
assert_eq!(r.checked_pow(0), Some(1 as $T));
- assert_eq!(r.overflowing_pow(2), (4 as $T,false));
- assert_eq!(r.overflowing_pow(0), (1 as $T,false));
+ assert_eq!(r.overflowing_pow(2), (4 as $T, false));
+ assert_eq!(r.overflowing_pow(0), (1 as $T, false));
assert_eq!(r.saturating_pow(2), 4 as $T);
assert_eq!(r.saturating_pow(0), 1 as $T);
@@ -206,7 +206,7 @@ macro_rules! uint_module {
// thussaturating_pow the overflowing result is exactly 1.
assert_eq!(r.wrapping_pow(2), 1 as $T);
assert_eq!(r.checked_pow(2), None);
- assert_eq!(r.overflowing_pow(2), (1 as $T,true));
+ assert_eq!(r.overflowing_pow(2), (1 as $T, true));
assert_eq!(r.saturating_pow(2), MAX);
}
}
From d5d7ca29958dd13b8543fa471d7d20ec723daf1c Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Thu, 16 Jul 2020 15:20:16 +0800
Subject: [PATCH 09/11] add whitespace
---
src/libcore/tests/num/int_macros.rs | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/src/libcore/tests/num/int_macros.rs b/src/libcore/tests/num/int_macros.rs
index 3293a6a8ef894..2eb7146da2716 100644
--- a/src/libcore/tests/num/int_macros.rs
+++ b/src/libcore/tests/num/int_macros.rs
@@ -274,7 +274,7 @@ macro_rules! int_module {
// thussaturating_pow the overflowing result is exactly 1.
assert_eq!(r.wrapping_pow(2), 1 as $T);
assert_eq!(r.checked_pow(2), None);
- assert_eq!(r.overflowing_pow(2), (1 as $T,true));
+ assert_eq!(r.overflowing_pow(2), (1 as $T, true));
assert_eq!(r.saturating_pow(2), MAX);
//test for negative exponent.
r = -2 as $T;
@@ -287,9 +287,9 @@ macro_rules! int_module {
assert_eq!(r.checked_pow(2), Some(4 as $T));
assert_eq!(r.checked_pow(3), Some(-8 as $T));
assert_eq!(r.checked_pow(0), Some(1 as $T));
- assert_eq!(r.overflowing_pow(2), (4 as $T,false));
- assert_eq!(r.overflowing_pow(3), (-8 as $T,false));
- assert_eq!(r.overflowing_pow(0), (1 as $T,false));
+ assert_eq!(r.overflowing_pow(2), (4 as $T, false));
+ assert_eq!(r.overflowing_pow(3), (-8 as $T, false));
+ assert_eq!(r.overflowing_pow(0), (1 as $T, false));
assert_eq!(r.saturating_pow(2), 4 as $T);
assert_eq!(r.saturating_pow(3), -8 as $T);
assert_eq!(r.saturating_pow(0), 1 as $T);
From 7599e01e92ec585e35726b1ea28f13c0c6f69682 Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Thu, 16 Jul 2020 15:20:44 +0800
Subject: [PATCH 10/11] add whitespace
---
src/libcore/tests/num/int_macros.rs | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/libcore/tests/num/int_macros.rs b/src/libcore/tests/num/int_macros.rs
index 2eb7146da2716..e9046f6d26af0 100644
--- a/src/libcore/tests/num/int_macros.rs
+++ b/src/libcore/tests/num/int_macros.rs
@@ -262,8 +262,8 @@ macro_rules! int_module {
assert_eq!(r.wrapping_pow(0), 1 as $T);
assert_eq!(r.checked_pow(2), Some(4 as $T));
assert_eq!(r.checked_pow(0), Some(1 as $T));
- assert_eq!(r.overflowing_pow(2), (4 as $T,false));
- assert_eq!(r.overflowing_pow(0), (1 as $T,false));
+ assert_eq!(r.overflowing_pow(2), (4 as $T, false));
+ assert_eq!(r.overflowing_pow(0), (1 as $T, false));
assert_eq!(r.saturating_pow(2), 4 as $T);
assert_eq!(r.saturating_pow(0), 1 as $T);
From 364cacb5840c1d96a8b4c1f4d62652200c57470d Mon Sep 17 00:00:00 2001
From: Neutron3529 <qweytr_1@163.com>
Date: Thu, 16 Jul 2020 15:53:18 +0800
Subject: [PATCH 11/11] delete extra line
---
src/libcore/tests/num/int_macros.rs | 1 -
1 file changed, 1 deletion(-)
diff --git a/src/libcore/tests/num/int_macros.rs b/src/libcore/tests/num/int_macros.rs
index e9046f6d26af0..58a585669122c 100644
--- a/src/libcore/tests/num/int_macros.rs
+++ b/src/libcore/tests/num/int_macros.rs
@@ -252,7 +252,6 @@ macro_rules! int_module {
assert_eq!($T::from_str_radix("-9", 2).ok(), None::<$T>);
}
-
#[test]
fn test_pow() {
let mut r = 2 as $T;