Check if output is immediate value

src/librustc_codegen_llvm/asm.rs

@@ -29,11 +29,17 @@ impl AsmBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
         let mut indirect_outputs = vec![];
         for (i, (out, &place)) in ia.outputs.iter().zip(&outputs).enumerate() {
             if out.is_rw {
-                inputs.push(self.load_operand(place).immediate());
+                let operand = self.load_operand(place);
+                if let OperandValue::Immediate(_) = operand.val {
+                    inputs.push(operand.immediate());
+                }
                 ext_constraints.push(i.to_string());
             }
             if out.is_indirect {
-                indirect_outputs.push(self.load_operand(place).immediate());
+                let operand = self.load_operand(place);
+                if let OperandValue::Immediate(_) = operand.val {
+                    indirect_outputs.push(operand.immediate());
+                }
             } else {
                 output_types.push(place.layout.llvm_type(self.cx()));
             }

src/test/ui/asm/issue-62046.rs

@@ -0,0 +1,11 @@
+// build-fail
+// ignore-emscripten no asm! support
+
+#![feature(asm)]
+
+fn main() {
+    unsafe {
+        asm!("nop" : "+r"("r15"));
+        //~^ malformed inline assembly
+    }
+}

src/test/ui/asm/issue-62046.stderr

@@ -0,0 +1,11 @@
+error[E0668]: malformed inline assembly
+  --> $DIR/issue-62046.rs:8:9
+   |
+LL |         asm!("nop" : "+r"("r15"));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0668`.