1 files changed, 22 insertions, 0 deletions
diff --git a/src/librustc_codegen_llvm/diagnostics.rs b/src/librustc_codegen_llvm/diagnostics.rs
index 94776f17c79..242b7a1a119 100644
--- a/src/librustc_codegen_llvm/diagnostics.rs
+++ b/src/librustc_codegen_llvm/diagnostics.rs
@@ -47,4 +47,26 @@ unsafe { simd_add(i32x2(0, 0), i32x2(1, 2)); } // ok!
 ```
 "##,
 
+E0668: r##"
+Malformed inline assembly rejected by LLVM.
+
+LLVM checks the validity of the constraints and the assembly string passed to
+it. This error implies that LLVM seems something wrong with the inline
+assembly call.
+
+In particular, it can happen if you forgot the closing bracket of a register
+constraint (see issue #51430):
+```ignore (error-emitted-at-codegen-which-cannot-be-handled-by-compile_fail)
+#![feature(asm)]
+
+fn main() {
+    let rax: u64;
+    unsafe {
+        asm!("" :"={rax"(rax));
+        println!("Accumulator is: {}", rax);
+    }
+}
+```
+"##,
+
 }