WIP performance test

Author: Zoxc

src/bootstrap/bin/rustc.rs

@@ -74,7 +74,7 @@ fn main() {
         if let Some(profile) = env::var_os("RUSTC_TUNE_COMPILER_CODEGEN_UNITS") {
             let cgus = match crate_name {
                 // This crate is large and at the tail of the compiler crates, give it extra CGUs.
-                "rustc_query_impl" => Some(96),
+                //"rustc_query_impl" => Some(96),
                 // This compiles after all other crates so give it default CGUs to speed it up.
                 "rustc_driver" => None,
                 _ => {

src/bootstrap/builder.rs

@@ -1885,10 +1885,7 @@ impl<'a> Builder<'a> {
                 cargo.env(profile_var("CODEGEN_UNITS"), n.to_string());
             }
             (Mode::Rustc, _, _) => {
-                cargo.env(
-                    "RUSTC_TUNE_COMPILER_CODEGEN_UNITS",
-                    if self.config.rust_codegen_units_fast { "fast" } else { "1" },
-                );
+                cargo.env("RUSTC_TUNE_COMPILER_CODEGEN_UNITS", "fast");
             }
             _ => {
                 // Don't set anything