bootstrap: get rid of TEST_MIRI env var

src/bootstrap/bin/rustc.rs

@@ -285,20 +285,6 @@ fn main() {
             }
         }
 
-        // When running miri tests, we need to generate MIR for all libraries
-        if env::var("TEST_MIRI").ok().map_or(false, |val| val == "true") {
-            // The flags here should be kept in sync with `add_miri_default_args`
-            // in miri's `src/lib.rs`.
-            cmd.arg("-Zalways-encode-mir");
-            cmd.arg("--cfg=miri");
-            // These options are preferred by miri, to be able to perform better validation,
-            // but the bootstrap compiler might not understand them.
-            if stage != "0" {
-                cmd.arg("-Zmir-emit-retag");
-                cmd.arg("-Zmir-opt-level=0");
-            }
-        }
-
         if let Ok(map) = env::var("RUSTC_DEBUGINFO_MAP") {
             cmd.arg("--remap-path-prefix").arg(&map);
         }

src/bootstrap/builder.rs

@@ -981,7 +981,6 @@ pub fn cargo(
                     PathBuf::from("/path/to/nowhere/rustdoc/not/required")
                 },
             )
-            .env("TEST_MIRI", self.config.test_miri.to_string())
             .env("RUSTC_ERROR_METADATA_DST", self.extended_error_dir());
 
         if let Some(host_linker) = self.linker(compiler.host) {