Mark inout asm! operands as used in liveness pass

1 files changed, 36 insertions, 0 deletions

diff --git a/src/test/ui/liveness/liveness-issue-77915.rs b/src/test/ui/liveness/liveness-issue-77915.rs
new file mode 100644
index 00000000000..300e4ad8b01
--- /dev/null
+++ b/src/test/ui/liveness/liveness-issue-77915.rs
@@ -0,0 +1,36 @@
+// Ensure inout asm! operands are marked as used by the liveness pass
+
+// only-x86_64
+// check-pass
+
+#![feature(asm)]
+#![allow(dead_code)]
+#![deny(unused_variables)]
+
+// Tests the single variable inout case
+unsafe fn rep_movsb(mut dest: *mut u8, mut src: *const u8, mut n: usize) -> *mut u8 {
+    while n != 0 {
+        asm!(
+            "rep movsb",
+            inout("rcx") n,
+            inout("rsi") src,
+            inout("rdi") dest,
+        );
+    }
+    dest
+}
+
+// Tests the split inout case
+unsafe fn rep_movsb2(mut dest: *mut u8, mut src: *const u8, mut n: usize) -> *mut u8 {
+    while n != 0 {
+        asm!(
+            "rep movsb",
+            inout("rcx") n,
+            inout("rsi") src => src,
+            inout("rdi") dest,
+        );
+    }
+    dest
+}
+
+fn main() {}