Fix a typo in rust-lang#75781

Author: Amanieu

src/librustc_codegen_llvm/asm.rs

@@ -485,7 +485,7 @@ fn reg_to_llvm(reg: InlineAsmRegOrRegClass, layout: Option<&TyAndLayout<'tcx>>)
                 format!("{{{}{}}}", class, idx)
             } else if reg == InlineAsmReg::AArch64(AArch64InlineAsmReg::x30) {
                 // LLVM doesn't recognize x30
-                "lr".to_string()
+                "{lr}".to_string()
             } else {
                 format!("{{{}}}", reg.name())
             }

src/test/assembly/asm/aarch64-types.rs

@@ -555,6 +555,11 @@ check_reg!(v0_f32x4 f32x4 "s0" "fmov");
 check_reg!(v0_f64x2 f64x2 "s0" "fmov");
 
 // Regression test for #75761
+// CHECK-LABEL: issue_75761:
+// CHECK: stp {{{.*}}}lr
+// CHECK: //APP
+// CHECK: //NO_APP
+// CHECK: ldp {{{.*}}}lr
 pub unsafe fn issue_75761() {
     asm!("", out("v0") _, out("x30") _);
 }