Merge pull request #1921 from a4lg/riscv-inline-asm-general-improvements

RISC-V: Improvements of inline assembly uses

Author: sayantn

crates/core_arch/src/riscv64/mod.rs

@@ -20,7 +20,12 @@ pub use zk::*;
 #[unstable(feature = "riscv_ext_intrinsics", issue = "114544")]
 pub unsafe fn hlv_wu(src: *const u32) -> u32 {
     let value: u32;
-    asm!(".insn i 0x73, 0x4, {}, {}, 0x681", out(reg) value, in(reg) src, options(readonly, nostack));
+    asm!(
+        ".insn i 0x73, 0x4, {}, {}, 0x681",
+        lateout(reg) value,
+        in(reg) src,
+        options(readonly, nostack, preserves_flags)
+    );
     value
 }
 
@@ -38,7 +43,12 @@ pub unsafe fn hlv_wu(src: *const u32) -> u32 {
 #[unstable(feature = "riscv_ext_intrinsics", issue = "114544")]
 pub unsafe fn hlv_d(src: *const i64) -> i64 {
     let value: i64;
-    asm!(".insn i 0x73, 0x4, {}, {}, 0x6C0", out(reg) value, in(reg) src, options(readonly, nostack));
+    asm!(
+        ".insn i 0x73, 0x4, {}, {}, 0x6C0",
+        lateout(reg) value,
+        in(reg) src,
+        options(readonly, nostack, preserves_flags)
+    );
     value
 }
 
@@ -53,5 +63,10 @@ pub unsafe fn hlv_d(src: *const i64) -> i64 {
 #[inline]
 #[unstable(feature = "riscv_ext_intrinsics", issue = "114544")]
 pub unsafe fn hsv_d(dst: *mut i64, src: i64) {
-    asm!(".insn r 0x73, 0x4, 0x37, x0, {}, {}", in(reg) dst, in(reg) src, options(nostack));
+    asm!(
+        ".insn r 0x73, 0x4, 0x37, x0, {}, {}",
+        in(reg) dst,
+        in(reg) src,
+        options(nostack, preserves_flags)
+    );
 }