optimize zipping over array iterators

1 files changed, 25 insertions, 0 deletions

diff --git a/tests/assembly/libs/issue-115339-zip-arrays.rs b/tests/assembly/libs/issue-115339-zip-arrays.rs
new file mode 100644
index 00000000000..26b7b9770bc
--- /dev/null
+++ b/tests/assembly/libs/issue-115339-zip-arrays.rs
@@ -0,0 +1,25 @@
+// assembly-output: emit-asm
+// # zen3 previously exhibited odd vectorization
+// compile-flags: --crate-type=lib -Ctarget-cpu=znver3 -O
+// only-x86_64
+// ignore-sgx
+
+use std::iter;
+
+// previously this produced a long chain of
+// 56:  vpextrb $6, %xmm0, %ecx
+// 57:  orb %cl, 22(%rsi)
+// 58:  vpextrb $7, %xmm0, %ecx
+// 59:  orb %cl, 23(%rsi)
+// [...]
+
+// CHECK-LABEL: zip_arrays:
+#[no_mangle]
+pub fn zip_arrays(mut a: [u8; 32], b: [u8; 32]) -> [u8; 32] {
+    // CHECK-NOT: vpextrb
+    // CHECK-NOT: orb %cl
+    // CHECK: vorps
+    iter::zip(&mut a, b).for_each(|(a, b)| *a |= b);
+    // CHECK: retq
+    a
+}