Auto merge of #117912 - GeorgeWort:master, r=petrochenkov

Name explicit registers in conflict register errors for inline assembly

compiler/rustc_ast/src/ast.rs

@@ -2251,6 +2251,18 @@ pub enum InlineAsmOperand {
     },
 }
 
+impl InlineAsmOperand {
+    pub fn reg(&self) -> Option<&InlineAsmRegOrRegClass> {
+        match self {
+            Self::In { reg, .. }
+            | Self::Out { reg, .. }
+            | Self::InOut { reg, .. }
+            | Self::SplitInOut { reg, .. } => Some(reg),
+            Self::Const { .. } | Self::Sym { .. } => None,
+        }
+    }
+}
+
 /// Inline assembly.
 ///
 /// E.g., `asm!("NOP");`.