Merge pull request #484 from RalfJung/mir-opt

Test with opt levels 0 and 1

Author: RalfJung

README.md

@@ -55,6 +55,14 @@ miri` to run your project, if it is a bin project, or run
 `MIRI_SYSROOT=~/.xargo/HOST cargo +nightly miri test` to run all tests in your
 project through Miri.
 
+## Miri `-Z` flags
+
+Miri adds some extra `-Z` flags to control its behavior:
+
+* `-Zmiri-start-fn`: This makes interpretation start with `lang_start` (defined
+  in libstd) instead of starting with `main`.  Requires full MIR!
+* `-Zmiri-disable-validation` disables enforcing the validity invariant.
+
 ## Development and Debugging
 
 Since the heart of Miri (the main interpreter engine) lives in rustc, working on

tests/compiletest.rs

@@ -104,7 +104,11 @@ fn miri_pass(sysroot: &Path, path: &str, target: &str, host: &str, need_fullmir:
         flags.push("-Zmiri-start-fn".to_owned());
     }
     if opt {
-        flags.push("-Zmir-opt-level=3".to_owned());
+        // FIXME: Using level 1 (instead of 3) for now, as the optimizer is pretty broken
+        // and crashes...
+        // Level 0 and 1 are not the same, so this still gives us *some* coverage.
+        // See https://github.com/rust-lang/rust/issues/50411
+        flags.push("-Zmir-opt-level=1".to_owned());
     } else {
         flags.push("-Zmir-opt-level=0".to_owned());
         // For now, only validate without optimizations.  Inlining breaks validation.
@@ -187,9 +191,7 @@ fn test() {
     // uses `libtest` which runs jobs in parallel.
 
     run_pass_miri(false);
-    // FIXME: Disabled for now, as the optimizer is pretty broken and crashes...
-    // See https://github.com/rust-lang/rust/issues/50411
-    //run_pass_miri(true);
+    run_pass_miri(true);
 
     compile_fail_miri();
 }