Make validate_mir ensure the final MIR for all bodies

compiler/rustc_interface/src/passes.rs

@@ -818,6 +818,19 @@ fn run_required_analyses(tcx: TyCtxt<'_>) {
     });
     sess.time("layout_testing", || layout_test::test_layout(tcx));
     sess.time("abi_testing", || abi_test::test_abi(tcx));
+
+    // If `-Zvalidate-mir` is set, we also want to compute the final MIR for each item
+    // (either its `mir_for_ctfe` or `optimized_mir`) since that helps uncover any bugs
+    // in MIR optimizations that may only be reachable through codegen, or other codepaths
+    // that requires the optimized/ctfe MIR, such as polymorphization, coroutine bodies,
+    // or evaluating consts.
+    if tcx.sess.opts.unstable_opts.validate_mir {
+        sess.time("ensuring_final_MIR_is_computable", || {
+            tcx.hir().par_body_owners(|def_id| {
+                tcx.instance_mir(ty::InstanceKind::Item(def_id.into()));
+            });
+        });
+    }
 }
 
 /// Runs the type-checking, region checking and other miscellaneous analysis

tests/crashes/121127.rs

@@ -1,5 +1,5 @@
 //@ known-bug: #121127
-//@ compile-flags: -Zpolymorphize=on -Zinline-mir=yes -C debuginfo=2
+//@ compile-flags: -Zvalidate-mir -Zinline-mir=yes -C debuginfo=2
 // Note that as of PR#123949 this only crashes with debuginfo enabled
 
 #![feature(specialization)]

tests/crashes/122909.rs

@@ -1,4 +1,4 @@
-//@ compile-flags: -Zpolymorphize=on -Zinline-mir=yes
+//@ compile-flags: -Zvalidate-mir -Zinline-mir=yes
 //@ known-bug: #122909
 
 

tests/crashes/126896.rs

@@ -1,5 +1,5 @@
 //@ known-bug: rust-lang/rust#126896
-//@ compile-flags: -Zpolymorphize=on -Zinline-mir=yes
+//@ compile-flags: -Zvalidate-mir -Zinline-mir=yes
 
 #![feature(type_alias_impl_trait)]
 type Two<'a, 'b> = impl std::fmt::Debug;