RISC-V: Use .insn on (Zkne or Zknd) intrinsics

Using the inline assembly and `.insn` could avoid current issues regarding
intrinsics available when either Zknd or Zkne is available.

Note that, coincidental success of the testing process depends on the
possibly flaky disassembler behavior (which attempts to disassemble
instructions *not* enabled on the target of the output object file) and
should be removed now or if anything breaks.

Author: a4lg

crates/core_arch/src/riscv64/zk.rs

@@ -1,6 +1,8 @@
 #[cfg(test)]
 use stdarch_test::assert_instr;
 
+use crate::arch::asm;
+
 unsafe extern "unadjusted" {
     #[link_name = "llvm.riscv.aes64es"]
     fn _aes64es(rs1: i64, rs2: i64) -> i64;
@@ -14,12 +16,6 @@ unsafe extern "unadjusted" {
     #[link_name = "llvm.riscv.aes64dsm"]
     fn _aes64dsm(rs1: i64, rs2: i64) -> i64;
 
-    #[link_name = "llvm.riscv.aes64ks1i"]
-    fn _aes64ks1i(rs1: i64, rnum: i32) -> i64;
-
-    #[link_name = "llvm.riscv.aes64ks2"]
-    fn _aes64ks2(rs1: i64, rs2: i64) -> i64;
-
     #[link_name = "llvm.riscv.aes64im"]
     fn _aes64im(rs1: i64) -> i64;
 
@@ -135,13 +131,23 @@ pub fn aes64dsm(rs1: u64, rs2: u64) -> u64 {
 /// The `RNUM` parameter is expected to be a constant value inside the range of `0..=10`.
 //#[target_feature(enable = "zkne", enable = "zknd")] // TODO: zkne_or_zknd
 #[rustc_legacy_const_generics(1)]
-#[cfg_attr(test, assert_instr(aes64ks1i, RNUM = 0))]
+#[cfg_attr(test, assert_instr(aes64ks1i, RNUM = 0))] // REMOVE if anything goes wrong
 #[inline]
 #[unstable(feature = "riscv_ext_intrinsics", issue = "114544")]
 pub fn aes64ks1i<const RNUM: u8>(rs1: u64) -> u64 {
     static_assert!(RNUM <= 10);
 
-    unsafe { _aes64ks1i(rs1 as i64, RNUM as i32) as u64 }
+    unsafe {
+        let rd: u64;
+        asm!(
+            ".insn i 0x13, 0x1, {}, {}, {}",
+            lateout(reg) rd,
+            in(reg) rs1,
+            const 0x310 + (RNUM & 0x0f) as u16,
+            options(pure, nomem, nostack)
+        );
+        rd
+    }
 }
 
 /// This instruction implements part of the KeySchedule operation for the AES Block cipher.
@@ -156,11 +162,15 @@ pub fn aes64ks1i<const RNUM: u8>(rs1: u64) -> u64 {
 ///
 /// Section: 3.11
 //#[target_feature(enable = "zkne", enable = "zknd")] // TODO: zkne_or_zknd
-#[cfg_attr(test, assert_instr(aes64ks2))]
+#[cfg_attr(test, assert_instr(aes64ks2))] // REMOVE if anything goes wrong
 #[inline]
 #[unstable(feature = "riscv_ext_intrinsics", issue = "114544")]
 pub fn aes64ks2(rs1: u64, rs2: u64) -> u64 {
-    unsafe { _aes64ks2(rs1 as i64, rs2 as i64) as u64 }
+    unsafe {
+        let rd: u64;
+        asm!(".insn r 0x33, 0x0, 0x3f, {}, {}, {}", lateout(reg) rd, in(reg) rs1, in(reg) rs2, options(pure, nomem, nostack));
+        rd
+    }
 }
 
 /// This instruction accelerates the inverse MixColumns step of the AES Block Cipher, and is used to aid creation of