Auto merge of #74724 - Manishearth:rollup-plbt8fe, r=Manishearth

Rollup of 8 pull requests

Successful merges:

 - #72954 (revise RwLock for HermitCore)
 - #74367 (Rearrange the pipeline of `pow` to gain efficiency)
 - #74491 (Optimize away BitAnd and BitOr when possible)
 - #74639 (Downgrade glibc to 2.11.1 for ppc, ppc64 and s390x)
 - #74661 (Refactor `region_name`: add `RegionNameHighlight`)
 - #74692 (delay_span_bug instead of silent ignore)
 - #74698 (fixed error reporting for mismatched traits)
 - #74715 (Add a system for creating diffs across multiple mir optimizations.)

Failed merges:

r? @ghost

Cargo.lock

@@ -1242,9 +1242,9 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.14"
+version = "0.1.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b9586eedd4ce6b3c498bc3b4dd92fc9f11166aa908a914071953768066c67909"
+checksum = "3deed196b6e7f9e44a2ae8d94225d80302d81208b1bb673fd21fe634645c85a9"
 dependencies = [
  "compiler_builtins",
  "libc",

src/ci/docker/README.md

@@ -238,7 +238,7 @@ For targets: `powerpc-unknown-linux-gnu`
 - Target options > Emit assembly for CPU = powerpc -- pure 32-bit PowerPC
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
-- C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
+- C-library > glibc version = 2.11.1 -- ~SLE11-SP4 glibc
 - C compiler > gcc version = 5.2.0
 - C compiler > C++ = ENABLE -- to cross compile LLVM
 
@@ -255,7 +255,7 @@ For targets: `powerpc64-unknown-linux-gnu`
 - Target options > Tune for CPU = power6 -- (+)
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
-- C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
+- C-library > glibc version = 2.11.1 -- ~SLE11-SP4 glibc
 - C compiler > gcc version = 5.2.0
 - C compiler > C++ = ENABLE -- to cross compile LLVM
 
@@ -272,7 +272,7 @@ For targets: `s390x-unknown-linux-gnu`
 - Target options > Bitness = 64-bit
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
-- C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
+- C-library > glibc version = 2.11.1 -- ~SLE11-SP4 glibc
 - C compiler > gcc version = 5.2.0
 - C compiler > gcc extra config = --with-arch=z10 -- LLVM's minimum support
 - C compiler > C++ = ENABLE -- to cross compile LLVM

src/ci/docker/host-x86_64/dist-powerpc-linux/powerpc-linux-gnu.config

@@ -290,7 +290,7 @@ CT_BINUTILS_EXTRA_CONFIG_ARRAY=""
 # C-library
 #
 CT_LIBC="glibc"
-CT_LIBC_VERSION="2.12.2"
+CT_LIBC_VERSION="2.11.1"
 CT_LIBC_glibc=y
 # CT_LIBC_musl is not set
 # CT_LIBC_uClibc is not set
@@ -309,9 +309,9 @@ CT_THREADS="nptl"
 # CT_LIBC_GLIBC_V_2_14_1 is not set
 # CT_LIBC_GLIBC_V_2_14 is not set
 # CT_LIBC_GLIBC_V_2_13 is not set
-CT_LIBC_GLIBC_V_2_12_2=y
+# CT_LIBC_GLIBC_V_2_12_2 is not set
 # CT_LIBC_GLIBC_V_2_12_1 is not set
-# CT_LIBC_GLIBC_V_2_11_1 is not set
+CT_LIBC_GLIBC_V_2_11_1=y
 # CT_LIBC_GLIBC_V_2_11 is not set
 # CT_LIBC_GLIBC_V_2_10_1 is not set
 # CT_LIBC_GLIBC_V_2_9 is not set

src/ci/docker/host-x86_64/dist-powerpc64-linux/powerpc64-linux-gnu.config

@@ -290,7 +290,7 @@ CT_BINUTILS_EXTRA_CONFIG_ARRAY=""
 # C-library
 #
 CT_LIBC="glibc"
-CT_LIBC_VERSION="2.12.2"
+CT_LIBC_VERSION="2.11.1"
 CT_LIBC_glibc=y
 # CT_LIBC_musl is not set
 # CT_LIBC_uClibc is not set
@@ -309,9 +309,9 @@ CT_THREADS="nptl"
 # CT_LIBC_GLIBC_V_2_14_1 is not set
 # CT_LIBC_GLIBC_V_2_14 is not set
 # CT_LIBC_GLIBC_V_2_13 is not set
-CT_LIBC_GLIBC_V_2_12_2=y
+# CT_LIBC_GLIBC_V_2_12_2 is not set
 # CT_LIBC_GLIBC_V_2_12_1 is not set
-# CT_LIBC_GLIBC_V_2_11_1 is not set
+CT_LIBC_GLIBC_V_2_11_1=y
 # CT_LIBC_GLIBC_V_2_11 is not set
 # CT_LIBC_GLIBC_V_2_10_1 is not set
 # CT_LIBC_GLIBC_V_2_9 is not set

src/ci/docker/host-x86_64/dist-s390x-linux/s390x-linux-gnu.config

@@ -270,7 +270,7 @@ CT_BINUTILS_EXTRA_CONFIG_ARRAY=""
 # C-library
 #
 CT_LIBC="glibc"
-CT_LIBC_VERSION="2.12.2"
+CT_LIBC_VERSION="2.11.1"
 CT_LIBC_glibc=y
 # CT_LIBC_musl is not set
 # CT_LIBC_uClibc is not set
@@ -289,9 +289,9 @@ CT_THREADS="nptl"
 # CT_LIBC_GLIBC_V_2_14_1 is not set
 # CT_LIBC_GLIBC_V_2_14 is not set
 # CT_LIBC_GLIBC_V_2_13 is not set
-CT_LIBC_GLIBC_V_2_12_2=y
+# CT_LIBC_GLIBC_V_2_12_2 is not set
 # CT_LIBC_GLIBC_V_2_12_1 is not set
-# CT_LIBC_GLIBC_V_2_11_1 is not set
+CT_LIBC_GLIBC_V_2_11_1=y
 # CT_LIBC_GLIBC_V_2_11 is not set
 # CT_LIBC_GLIBC_V_2_10_1 is not set
 # CT_LIBC_GLIBC_V_2_9 is not set

src/libcore/num/mod.rs

@@ -1095,6 +1095,9 @@ $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;
 
@@ -1105,15 +1108,11 @@ $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)))
             }
         }
 
@@ -1622,6 +1621,9 @@ $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;
 
@@ -1633,14 +1635,11 @@ $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)
             }
         }
 
@@ -1989,6 +1988,9 @@ $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;
@@ -2007,16 +2009,13 @@ $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;
-                }
-
-                (acc, overflown)
+                r = acc.overflowing_mul(base);
+                r.1 |= overflown;
+                r
             }
         }
 
@@ -2040,6 +2039,9 @@ $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;
 
@@ -2051,14 +2053,11 @@ $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
             }
         }
 
@@ -3295,6 +3294,9 @@ 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;
 
@@ -3306,14 +3308,12 @@ 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)))
             }
         }
 
@@ -3704,6 +3704,9 @@ 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;
 
@@ -3715,14 +3718,11 @@ 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)
             }
         }
 
@@ -4029,6 +4029,9 @@ 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;
@@ -4047,16 +4050,14 @@ 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
             }
         }
 
@@ -4077,6 +4078,9 @@ 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;
 
@@ -4088,14 +4092,11 @@ 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
         }
     }
 

src/libcore/tests/num/int_macros.rs

@@ -255,12 +255,43 @@ macro_rules! int_module {
             #[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(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(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);
             }
         }
     };