Auto merge of #86416 - Amanieu:asm_clobber_only, r=nagisa

Add clobber-only register classes for asm!

These are needed to properly express a function call ABI using a clobber
list, even though we don't support passing actual values into/out of
these registers.

1 files changed, 19 insertions, 0 deletions

diff --git a/src/test/codegen/asm-clobbers.rs b/src/test/codegen/asm-clobbers.rs
new file mode 100644
index 00000000000..9d7c8b5f155
--- /dev/null
+++ b/src/test/codegen/asm-clobbers.rs
@@ -0,0 +1,19 @@
+// compile-flags: -O
+// only-x86_64
+
+#![crate_type = "rlib"]
+#![feature(asm)]
+
+// CHECK-LABEL: @x87_clobber
+// CHECK: ~{st},~{st(1)},~{st(2)},~{st(3)},~{st(4)},~{st(5)},~{st(6)},~{st(7)}
+#[no_mangle]
+pub unsafe fn x87_clobber() {
+    asm!("foo", out("st") _);
+}
+
+// CHECK-LABEL: @mmx_clobber
+// CHECK: ~{st},~{st(1)},~{st(2)},~{st(3)},~{st(4)},~{st(5)},~{st(6)},~{st(7)}
+#[no_mangle]
+pub unsafe fn mmx_clobber() {
+    asm!("bar", out("mm0") _, out("mm1") _);
+}