Add _mm_clflushopt intrinsic

crates/core_arch/missing-x86.md

@@ -72,7 +72,7 @@
 
 <details><summary>["CLFLUSHOPT"]</summary><p>
 
-  * [ ] [`_mm_clflushopt`](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_mm_clflushopt)
+  * [x] [`_mm_clflushopt`](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_mm_clflushopt)
 </p></details>
 
 

crates/core_arch/src/x86/clflushopt.rs

@@ -0,0 +1,45 @@
+//! `CLFLUSHOPT` cache-line flush.
+
+#[cfg(test)]
+use stdarch_test::assert_instr;
+
+#[allow(improper_ctypes)]
+unsafe extern "C" {
+    #[link_name = "llvm.x86.clflushopt"]
+    fn clflushopt(p: *mut i8);
+}
+
+/// Invalidates from every level of the cache hierarchy the cache line that
+/// contains `p`.
+///
+/// Unlike [`_mm_clflush`], `CLFLUSHOPT` is only ordered with respect to older
+/// writes to the flushed cache line and with respect to fence/locked
+/// operations; it is *not* serialized against other `CLFLUSHOPT`/`CLFLUSH`
+/// instructions or unrelated stores. This makes flushing a range of lines
+/// substantially faster, but a fence (e.g. [`_mm_sfence`] or [`_mm_mfence`]) is
+/// required afterward to order the flushes against subsequent operations.
+///
+/// [Intel's documentation](https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm_clflushopt)
+///
+/// [`_mm_clflush`]: crate::arch::x86_64::_mm_clflush
+/// [`_mm_sfence`]: crate::arch::x86_64::_mm_sfence
+/// [`_mm_mfence`]: crate::arch::x86_64::_mm_mfence
+#[inline]
+#[target_feature(enable = "clflushopt")]
+#[cfg_attr(test, assert_instr(clflushopt))]
+#[unstable(feature = "simd_x86_clflushopt", issue = "157096")]
+pub unsafe fn _mm_clflushopt(p: *const u8) {
+    clflushopt(p as *mut i8);
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::core_arch::x86::*;
+    use stdarch_test::simd_test;
+
+    #[simd_test(enable = "clflushopt")]
+    unsafe fn test_mm_clflushopt() {
+        let x = 0_u8;
+        _mm_clflushopt(core::ptr::addr_of!(x));
+    }
+}

crates/core_arch/src/x86/mod.rs

@@ -692,6 +692,10 @@ mod adx;
 #[stable(feature = "simd_x86_adx", since = "1.33.0")]
 pub use self::adx::*;
 
+mod clflushopt;
+#[unstable(feature = "simd_x86_clflushopt", issue = "157096")]
+pub use self::clflushopt::*;
+
 #[cfg(test)]
 use stdarch_test::assert_instr;
 

crates/stdarch-verify/tests/x86-intel.rs

@@ -668,7 +668,7 @@ fn pointed_type(intrinsic: &Intrinsic) -> Result<Type, String> {
         {
             // AMX, KEYLOCKER and XSAVE intrinsics should take `*u8`
             U8
-        } else if intrinsic.name == "_mm_clflush" {
+        } else if intrinsic.name == "_mm_clflush" || intrinsic.name == "_mm_clflushopt" {
             // Just a false match in the following logic
             U8
         } else if ["_mm_storeu_si", "_mm_loadu_si"]