Rollup merge of #82808 - bjorn3:sync_cg_clif-2021-03-05, r=bjorn3

Sync rustc_codegen_cranelift

The main highlight of this sync is removal of support for the old x86 Cranelift backend. This made it possible to use native atomic instructions rather than hackishly using a global mutex. 128bit integer support has also seen a few bugfixes and performance improvements. And finally I have formatted everything using the same rustfmt config as the rest of this repo.

r? ``@ghost``

``@rustbot`` label +A-codegen +A-cranelift +T-compiler

Author: JohnTitor

compiler/rustc_codegen_cranelift/.cirrus.yml

@@ -0,0 +1,25 @@
+task:
+  name: freebsd
+  freebsd_instance:
+    image: freebsd-12-1-release-amd64
+  setup_rust_script:
+    - pkg install -y curl git bash
+    - curl https://sh.rustup.rs -sSf --output rustup.sh
+    - sh rustup.sh --default-toolchain none -y --profile=minimal
+  cargo_bin_cache:
+    folder: ~/.cargo/bin
+  target_cache:
+    folder: target
+  prepare_script:
+    - . $HOME/.cargo/env
+    - git config --global user.email "user@example.com"
+    - git config --global user.name "User"
+    - ./prepare.sh
+  test_script:
+    - . $HOME/.cargo/env
+    - # Enable backtraces for easier debugging
+    - export RUST_BACKTRACE=1
+    - # Reduce amount of benchmark runs as they are slow
+    - export COMPILE_RUNS=2
+    - export RUN_RUNS=2
+    - ./test.sh

compiler/rustc_codegen_cranelift/.github/workflows/main.yml

@@ -12,9 +12,6 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest]
-        env:
-          - BACKEND: ""
-          - BACKEND: --oldbe
 
     steps:
     - uses: actions/checkout@v2
@@ -54,7 +51,7 @@ jobs:
         export COMPILE_RUNS=2
         export RUN_RUNS=2
 
-        ./test.sh $BACKEND
+        ./test.sh
 
     - name: Package prebuilt cg_clif
       run: tar cvfJ cg_clif.tar.xz build