Test catch_unwind vanishing

We execpt the try intrinsic to be a direct call if in -Cpanic=abort mode, and
that catch_unwind optimizes out if calling a function that does not unwind.

src/test/codegen/catch-unwind.rs

@@ -0,0 +1,19 @@
+// compile-flags: -O
+
+#![crate_type = "lib"]
+
+extern "C" {
+    fn bar();
+}
+
+// CHECK-LABEL: @foo
+#[no_mangle]
+pub unsafe fn foo() -> i32 {
+    // CHECK: call void @bar
+    // CHECK: ret i32 0
+    std::panic::catch_unwind(|| {
+        bar();
+        0
+    })
+    .unwrap()
+}

src/test/codegen/try-panic-abort.rs

@@ -0,0 +1,17 @@
+// compile-flags: -C panic=abort -O
+
+#![crate_type = "lib"]
+#![feature(unwind_attributes, core_intrinsics)]
+
+extern "C" {
+    #[unwind(allow)]
+    fn bar(data: *mut u8);
+}
+
+// CHECK-LABEL: @foo
+#[no_mangle]
+pub unsafe fn foo() -> i32 {
+    // CHECK: call void @bar
+    // CHECK: ret i32 0
+    std::intrinsics::r#try(|x| bar(x), 0 as *mut u8, 0 as *mut u8)
+}