FileCheck const_prop_miscompile.

tests/mir-opt/const_prop/indirect_mutation.rs

@@ -0,0 +1,41 @@
+// unit-test: ConstProp
+// Check that we do not propagate past an indirect mutation.
+#![feature(raw_ref_op)]
+
+// EMIT_MIR indirect_mutation.foo.ConstProp.diff
+fn foo() {
+    // CHECK-LABEL: fn foo(
+    // CHECK: debug u => _1;
+    // CHECK: debug y => _3;
+    // CHECK: _1 = (const 1_i32,);
+    // CHECK: _2 = &mut (_1.0: i32);
+    // CHECK: (*_2) = const 5_i32;
+    // CHECK: _4 = (_1.0: i32);
+    // CHECK: _3 = Eq(move _4, const 5_i32);
+
+    let mut u = (1,);
+    *&mut u.0 = 5;
+    let y = { u.0 } == 5;
+}
+
+// EMIT_MIR indirect_mutation.bar.ConstProp.diff
+fn bar() {
+    // CHECK-LABEL: fn bar(
+    // CHECK: debug v => _1;
+    // CHECK: debug y => _4;
+    // CHECK: _3 = &raw mut (_1.0: i32);
+    // CHECK: (*_3) = const 5_i32;
+    // CHECK: _5 = (_1.0: i32);
+    // CHECK: _4 = Eq(move _5, const 5_i32);
+
+    let mut v = (1,);
+    unsafe {
+        *&raw mut v.0 = 5;
+    }
+    let y = { v.0 } == 5;
+}
+
+fn main() {
+    foo();
+    bar();
+}