Merge pull request #646 from rchaser53/issue-58645

use copy_op directly insteadof write_scalar

Author: RalfJung

src/intrinsic.rs

@@ -50,22 +50,30 @@ pub trait EvalContextExt<'a, 'mir, 'tcx: 'a+'mir>: crate::MiriEvalContextExt<'a,
 
             "atomic_load" |
             "atomic_load_relaxed" |
-            "atomic_load_acq" |
-            "volatile_load" => {
+            "atomic_load_acq" => {
                 let ptr = this.deref_operand(args[0])?;
                 let val = this.read_scalar(ptr.into())?; // make sure it fits into a scalar; otherwise it cannot be atomic
                 this.write_scalar(val, dest)?;
             }
 
+            "volatile_load" => {
+                let ptr = this.deref_operand(args[0])?;
+                this.copy_op(ptr.into(), dest)?;
+            }
+
             "atomic_store" |
             "atomic_store_relaxed" |
-            "atomic_store_rel" |
-            "volatile_store" => {
+            "atomic_store_rel" => {
                 let ptr = this.deref_operand(args[0])?;
                 let val = this.read_scalar(args[1])?; // make sure it fits into a scalar; otherwise it cannot be atomic
                 this.write_scalar(val, ptr.into())?;
             }
 
+            "volatile_store" => {
+                let ptr = this.deref_operand(args[0])?;
+                this.copy_op(args[1], ptr.into())?;
+            }
+
             "atomic_fence_acq" => {
                 // we are inherently singlethreaded and singlecored, this is a nop
             }

tests/run-pass/volatile.rs

@@ -0,0 +1,12 @@
+// related: #58645
+#![feature(core_intrinsics)]
+use std::intrinsics::{volatile_load, volatile_store};
+
+pub fn main() {
+    unsafe {
+        let i: &mut (isize, isize) = &mut (0, 0);
+        volatile_store(i, (1, 2));
+        assert_eq!(volatile_load(i), (1, 2));
+        assert_eq!(i, &mut (1, 2));
+    }
+}