Auto merge of rust-lang#129060 - matthiaskrgr:rollup-s72gpif, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#122884 (Optimize integer `pow` by removing the exit branch)
 - rust-lang#127857 (Allow to customize `// TODO:` comment for deprecated safe autofix)
 - rust-lang#129034 (Add `#[must_use]` attribute to `Coroutine` trait)
 - rust-lang#129049 (compiletest: Don't panic on unknown JSON-like output lines)
 - rust-lang#129050 (Emit a warning instead of an error if `--generate-link-to-definition` is used with other output formats than HTML)
 - rust-lang#129056 (Fix one usage of target triple in bootstrap)
 - rust-lang#129058 (Add mw back to review rotation)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

Diff for: core/src/lib.rs

@@ -170,6 +170,7 @@
 #![feature(internal_impls_macro)]
 #![feature(ip)]
 #![feature(is_ascii_octdigit)]
+#![feature(is_val_statically_known)]
 #![feature(isqrt)]
 #![feature(link_cfg)]
 #![feature(offset_of_enum)]

Diff for: core/src/num/int_macros.rs

@@ -1496,18 +1496,17 @@ macro_rules! int_impl {
             let mut base = self;
             let mut acc: Self = 1;
 
-            while exp > 1 {
+            loop {
                 if (exp & 1) == 1 {
                     acc = try_opt!(acc.checked_mul(base));
+                    // since exp!=0, finally the exp must be 1.
+                    if exp == 1 {
+                        return Some(acc);
+                    }
                 }
                 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.
-            acc.checked_mul(base)
         }
 
         /// Strict exponentiation. Computes `self.pow(exp)`, panicking if
@@ -1547,18 +1546,17 @@ macro_rules! int_impl {
             let mut base = self;
             let mut acc: Self = 1;
 
-            while exp > 1 {
+            loop {
                 if (exp & 1) == 1 {
                     acc = acc.strict_mul(base);
+                    // since exp!=0, finally the exp must be 1.
+                    if exp == 1 {
+                        return acc;
+                    }
                 }
                 exp /= 2;
                 base = base.strict_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.
-            acc.strict_mul(base)
         }
 
         /// Returns the square root of the number, rounded down.
@@ -2175,26 +2173,44 @@ macro_rules! int_impl {
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
+        #[rustc_allow_const_fn_unstable(is_val_statically_known)]
         pub const fn wrapping_pow(self, mut exp: u32) -> Self {
             if exp == 0 {
                 return 1;
             }
             let mut base = self;
             let mut acc: Self = 1;
 
-            while exp > 1 {
-                if (exp & 1) == 1 {
-                    acc = acc.wrapping_mul(base);
+            if intrinsics::is_val_statically_known(exp) {
+                while exp > 1 {
+                    if (exp & 1) == 1 {
+                        acc = acc.wrapping_mul(base);
+                    }
+                    exp /= 2;
+                    base = base.wrapping_mul(base);
                 }
-                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.
-            acc.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.
+                acc.wrapping_mul(base)
+            } else {
+                // This is faster than the above when the exponent is not known
+                // at compile time. We can't use the same code for the constant
+                // exponent case because LLVM is currently unable to unroll
+                // this loop.
+                loop {
+                    if (exp & 1) == 1 {
+                        acc = acc.wrapping_mul(base);
+                        // since exp!=0, finally the exp must be 1.
+                        if exp == 1 {
+                            return acc;
+                        }
+                    }
+                    exp /= 2;
+                    base = base.wrapping_mul(base);
+                }
+            }
         }
 
         /// Calculates `self` + `rhs`.
@@ -2690,9 +2706,14 @@ macro_rules! int_impl {
             // Scratch space for storing results of overflowing_mul.
             let mut r;
 
-            while exp > 1 {
+            loop {
                 if (exp & 1) == 1 {
                     r = acc.overflowing_mul(base);
+                    // since exp!=0, finally the exp must be 1.
+                    if exp == 1 {
+                        r.1 |= overflown;
+                        return r;
+                    }
                     acc = r.0;
                     overflown |= r.1;
                 }
@@ -2701,14 +2722,6 @@ macro_rules! int_impl {
                 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.
-            r = acc.overflowing_mul(base);
-            r.1 |= overflown;
-            r
         }
 
         /// Raises self to the power of `exp`, using exponentiation by squaring.
@@ -2728,26 +2741,45 @@ macro_rules! int_impl {
                       without modifying the original"]
         #[inline]
         #[rustc_inherit_overflow_checks]
+        #[rustc_allow_const_fn_unstable(is_val_statically_known)]
         pub const fn pow(self, mut exp: u32) -> Self {
             if exp == 0 {
                 return 1;
             }
             let mut base = self;
             let mut acc = 1;
 
-            while exp > 1 {
-                if (exp & 1) == 1 {
-                    acc = acc * base;
+            if intrinsics::is_val_statically_known(exp) {
+                while exp > 1 {
+                    if (exp & 1) == 1 {
+                        acc = acc * base;
+                    }
+                    exp /= 2;
+                    base = base * base;
                 }
-                exp /= 2;
-                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.
-            acc * 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.
+                acc * base
+            } else {
+                // This is faster than the above when the exponent is not known
+                // at compile time. We can't use the same code for the constant
+                // exponent case because LLVM is currently unable to unroll
+                // this loop.
+                loop {
+                    if (exp & 1) == 1 {
+                        acc = acc * base;
+                        // since exp!=0, finally the exp must be 1.
+                        if exp == 1 {
+                            return acc;
+                        }
+                    }
+                    exp /= 2;
+                    base = base * base;
+                }
+            }
         }
 
         /// Returns the square root of the number, rounded down.

Diff for: core/src/num/uint_macros.rs

@@ -1622,20 +1622,17 @@ macro_rules! uint_impl {
             let mut base = self;
             let mut acc: Self = 1;
 
-            while exp > 1 {
+            loop {
                 if (exp & 1) == 1 {
                     acc = try_opt!(acc.checked_mul(base));
+                    // since exp!=0, finally the exp must be 1.
+                    if exp == 1 {
+                        return Some(acc);
+                    }
                 }
                 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.
-
-            acc.checked_mul(base)
         }
 
         /// Strict exponentiation. Computes `self.pow(exp)`, panicking if
@@ -1675,18 +1672,17 @@ macro_rules! uint_impl {
             let mut base = self;
             let mut acc: Self = 1;
 
-            while exp > 1 {
+            loop {
                 if (exp & 1) == 1 {
                     acc = acc.strict_mul(base);
+                    // since exp!=0, finally the exp must be 1.
+                    if exp == 1 {
+                        return acc;
+                    }
                 }
                 exp /= 2;
                 base = base.strict_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.
-            acc.strict_mul(base)
         }
 
         /// Saturating integer addition. Computes `self + rhs`, saturating at
@@ -2138,26 +2134,44 @@ macro_rules! uint_impl {
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
+        #[rustc_allow_const_fn_unstable(is_val_statically_known)]
         pub const fn wrapping_pow(self, mut exp: u32) -> Self {
             if exp == 0 {
                 return 1;
             }
             let mut base = self;
             let mut acc: Self = 1;
 
-            while exp > 1 {
-                if (exp & 1) == 1 {
-                    acc = acc.wrapping_mul(base);
+            if intrinsics::is_val_statically_known(exp) {
+                while exp > 1 {
+                    if (exp & 1) == 1 {
+                        acc = acc.wrapping_mul(base);
+                    }
+                    exp /= 2;
+                    base = base.wrapping_mul(base);
                 }
-                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.
-            acc.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.
+                acc.wrapping_mul(base)
+            } else {
+                // This is faster than the above when the exponent is not known
+                // at compile time. We can't use the same code for the constant
+                // exponent case because LLVM is currently unable to unroll
+                // this loop.
+                loop {
+                    if (exp & 1) == 1 {
+                        acc = acc.wrapping_mul(base);
+                        // since exp!=0, finally the exp must be 1.
+                        if exp == 1 {
+                            return acc;
+                        }
+                    }
+                    exp /= 2;
+                    base = base.wrapping_mul(base);
+                }
+            }
         }
 
         /// Calculates `self` + `rhs`.
@@ -2603,9 +2617,14 @@ macro_rules! uint_impl {
             // Scratch space for storing results of overflowing_mul.
             let mut r;
 
-            while exp > 1 {
+            loop {
                 if (exp & 1) == 1 {
                     r = acc.overflowing_mul(base);
+                    // since exp!=0, finally the exp must be 1.
+                    if exp == 1 {
+                        r.1 |= overflown;
+                        return r;
+                    }
                     acc = r.0;
                     overflown |= r.1;
                 }
@@ -2614,15 +2633,6 @@ macro_rules! uint_impl {
                 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.
-            r = acc.overflowing_mul(base);
-            r.1 |= overflown;
-
-            r
         }
 
         /// Raises self to the power of `exp`, using exponentiation by squaring.
@@ -2640,26 +2650,45 @@ macro_rules! uint_impl {
                       without modifying the original"]
         #[inline]
         #[rustc_inherit_overflow_checks]
+        #[rustc_allow_const_fn_unstable(is_val_statically_known)]
         pub const fn pow(self, mut exp: u32) -> Self {
             if exp == 0 {
                 return 1;
             }
             let mut base = self;
             let mut acc = 1;
 
-            while exp > 1 {
-                if (exp & 1) == 1 {
-                    acc = acc * base;
+            if intrinsics::is_val_statically_known(exp) {
+                while exp > 1 {
+                    if (exp & 1) == 1 {
+                        acc = acc * base;
+                    }
+                    exp /= 2;
+                    base = base * base;
                 }
-                exp /= 2;
-                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.
-            acc * 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.
+                acc * base
+            } else {
+                // This is faster than the above when the exponent is not known
+                // at compile time. We can't use the same code for the constant
+                // exponent case because LLVM is currently unable to unroll
+                // this loop.
+                loop {
+                    if (exp & 1) == 1 {
+                        acc = acc * base;
+                        // since exp!=0, finally the exp must be 1.
+                        if exp == 1 {
+                            return acc;
+                        }
+                    }
+                    exp /= 2;
+                    base = base * base;
+                }
+            }
         }
 
         /// Returns the square root of the number, rounded down.