1 files changed, 16 insertions, 0 deletions
diff --git a/tests/codegen-llvm/slice-is-ascii.rs b/tests/codegen-llvm/slice-is-ascii.rs
new file mode 100644
index 00000000000..67537c871a0
--- /dev/null
+++ b/tests/codegen-llvm/slice-is-ascii.rs
@@ -0,0 +1,16 @@
+//@ only-x86_64
+//@ compile-flags: -C opt-level=3 -C target-cpu=x86-64
+#![crate_type = "lib"]
+
+/// Check that the fast-path of `is_ascii` uses a `pmovmskb` instruction.
+/// Platforms lacking an equivalent instruction use other techniques for
+/// optimizing `is_ascii`.
+// CHECK-LABEL: @is_ascii_autovectorized
+#[no_mangle]
+pub fn is_ascii_autovectorized(s: &[u8]) -> bool {
+    // CHECK: load <32 x i8>
+    // CHECK-NEXT: icmp slt <32 x i8>
+    // CHECK-NEXT: bitcast <32 x i1>
+    // CHECK-NEXT: icmp eq i32
+    s.is_ascii()
+}