1 files changed, 33 insertions, 0 deletions
diff --git a/tests/assembly-llvm/slice-is_ascii.rs b/tests/assembly-llvm/slice-is_ascii.rs
new file mode 100644
index 00000000000..e53cd5160cf
--- /dev/null
+++ b/tests/assembly-llvm/slice-is_ascii.rs
@@ -0,0 +1,33 @@
+//@ revisions: WIN LIN
+//@ [WIN] only-windows
+//@ [LIN] only-linux
+//@ assembly-output: emit-asm
+//@ compile-flags: --crate-type=lib -Copt-level=3 -C llvm-args=-x86-asm-syntax=intel
+//@ only-x86_64
+//@ ignore-sgx
+
+#![feature(str_internals)]
+
+// CHECK-LABEL: is_ascii_simple_demo:
+#[no_mangle]
+pub fn is_ascii_simple_demo(bytes: &[u8]) -> bool {
+    // Linux (System V): pointer is rdi; length is rsi
+    // Windows: pointer is rcx; length is rdx.
+
+    // CHECK-NOT: mov
+    // CHECK-NOT: test
+    // CHECK-NOT: cmp
+
+    // CHECK: .[[LOOPHEAD:.+]]:
+    // CHECK-NEXT: mov [[TEMP:.+]], [[LEN:rsi|rdx]]
+    // CHECK-NEXT: sub [[LEN]], 1
+    // CHECK-NEXT: jb .[[LOOPEXIT:.+]]
+    // CHECK-NEXT: cmp byte ptr [{{rdi|rcx}} + [[TEMP]] - 1], 0
+    // CHECK-NEXT: jns .[[LOOPHEAD]]
+
+    // CHECK-NEXT: .[[LOOPEXIT]]:
+    // CHECK-NEXT: test [[TEMP]], [[TEMP]]
+    // CHECK-NEXT: sete al
+    // CHECK-NEXT: ret
+    core::slice::is_ascii_simple(bytes)
+}