From 76857343845900e1f5dda72d9e6e8b10a0f79e24 Mon Sep 17 00:00:00 2001
From: Trevor Gross <tmgross@umich.edu>
Date: Thu, 16 May 2024 15:31:01 -0500
Subject: [PATCH] Add `powi` to `f16` and `f128`

This will unblock adding support to compiler_builtins
(<https://github.com/rust-lang/compiler-builtins/pull/614>), which will
then unblock adding tests for these new functions.
---
 library/core/src/intrinsics.rs | 12 ++++++++++++
 library/std/src/f128.rs        | 24 ++++++++++++++++++++++++
 library/std/src/f16.rs         | 24 ++++++++++++++++++++++++
 3 files changed, 60 insertions(+)

diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs
index d1450bf12ce72..d58e1dbb3e4d0 100644
--- a/library/core/src/intrinsics.rs
+++ b/library/core/src/intrinsics.rs
@@ -1594,6 +1594,12 @@ extern "rust-intrinsic" {
     #[rustc_nounwind]
     pub fn sqrtf64(x: f64) -> f64;
 
+    /// Raises an `f16` to an integer power.
+    ///
+    /// The stabilized version of this intrinsic is
+    /// [`f16::powi`](../../std/primitive.f16.html#method.powi)
+    #[rustc_nounwind]
+    pub fn powif16(a: f16, x: i32) -> f16;
     /// Raises an `f32` to an integer power.
     ///
     /// The stabilized version of this intrinsic is
@@ -1606,6 +1612,12 @@ extern "rust-intrinsic" {
     /// [`f64::powi`](../../std/primitive.f64.html#method.powi)
     #[rustc_nounwind]
     pub fn powif64(a: f64, x: i32) -> f64;
+    /// Raises an `f128` to an integer power.
+    ///
+    /// The stabilized version of this intrinsic is
+    /// [`f128::powi`](../../std/primitive.f128.html#method.powi)
+    #[rustc_nounwind]
+    pub fn powif128(a: f128, x: i32) -> f128;
 
     /// Returns the sine of an `f32`.
     ///
diff --git a/library/std/src/f128.rs b/library/std/src/f128.rs
index 4710d7c50b444..491235a872eaf 100644
--- a/library/std/src/f128.rs
+++ b/library/std/src/f128.rs
@@ -7,5 +7,29 @@
 #[cfg(test)]
 mod tests;
 
+#[cfg(not(test))]
+use crate::intrinsics;
+
 #[unstable(feature = "f128", issue = "116909")]
 pub use core::f128::consts;
+
+#[cfg(not(test))]
+impl f128 {
+    /// Raises a number to an integer power.
+    ///
+    /// Using this function is generally faster than using `powf`.
+    /// It might have a different sequence of rounding operations than `powf`,
+    /// so the results are not guaranteed to agree.
+    ///
+    /// # Unspecified precision
+    ///
+    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
+    /// can even differ within the same execution from one invocation to the next.
+    #[inline]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn powi(self, n: i32) -> f128 {
+        unsafe { intrinsics::powif128(self, n) }
+    }
+}
diff --git a/library/std/src/f16.rs b/library/std/src/f16.rs
index c36f9f5d4c6a8..1cb655ffabd84 100644
--- a/library/std/src/f16.rs
+++ b/library/std/src/f16.rs
@@ -7,5 +7,29 @@
 #[cfg(test)]
 mod tests;
 
+#[cfg(not(test))]
+use crate::intrinsics;
+
 #[unstable(feature = "f16", issue = "116909")]
 pub use core::f16::consts;
+
+#[cfg(not(test))]
+impl f16 {
+    /// Raises a number to an integer power.
+    ///
+    /// Using this function is generally faster than using `powf`.
+    /// It might have a different sequence of rounding operations than `powf`,
+    /// so the results are not guaranteed to agree.
+    ///
+    /// # Unspecified precision
+    ///
+    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
+    /// can even differ within the same execution from one invocation to the next.
+    #[inline]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f16", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn powi(self, n: i32) -> f16 {
+        unsafe { intrinsics::powif16(self, n) }
+    }
+}