Auto merge of #1523 - RalfJung:test-matrix, r=RalfJung

tweak test matrix

* test big-endian architecture
* test less on macOS host (it is slow)

ci.sh

@@ -43,9 +43,8 @@ if [ "${TRAVIS_OS_NAME:-}" == linux ]; then
   MIRI_TEST_TARGET=x86_64-apple-darwin run_tests
   MIRI_TEST_TARGET=i686-pc-windows-msvc run_tests
 elif [ "${TRAVIS_OS_NAME:-}" == osx ]; then
-  MIRI_TEST_TARGET=i686-unknown-linux-gnu run_tests
+  MIRI_TEST_TARGET=mips64-unknown-linux-gnuabi64 run_tests # big-endian architecture
   MIRI_TEST_TARGET=x86_64-pc-windows-msvc run_tests
-  MIRI_TEST_TARGET=i686-pc-windows-gnu run_tests
 elif [ "${CI_WINDOWS:-}" == True ]; then
   MIRI_TEST_TARGET=x86_64-unknown-linux-gnu run_tests
   MIRI_TEST_TARGET=x86_64-apple-darwin run_tests

tests/run-pass/transmute_fat2.rs

@@ -1,9 +1,13 @@
 fn main() {
-    #[cfg(target_pointer_width="64")]
+    #[cfg(all(target_endian="little", target_pointer_width="64"))]
     let bad = unsafe {
         std::mem::transmute::<u128, &[u8]>(42)
     };
-    #[cfg(target_pointer_width="32")]
+    #[cfg(all(target_endian="big", target_pointer_width="64"))]
+    let bad = unsafe {
+        std::mem::transmute::<u128, &[u8]>(42 << 64)
+    };
+    #[cfg(all(target_endian="little", target_pointer_width="32"))]
     let bad = unsafe {
         std::mem::transmute::<u64, &[u8]>(42)
     };

tests/run-pass/transmute_fat2.stderr

@@ -1 +1 @@
-thread 'main' panicked at 'index out of bounds: the len is 0 but the index is 0', $DIR/transmute_fat2.rs:11:5
+thread 'main' panicked at 'index out of bounds: the len is 0 but the index is 0', $DIR/transmute_fat2.rs:15:5