1 files changed, 59 insertions, 0 deletions
diff --git a/tests/codegen-llvm/simd/simd-wide-sum.rs b/tests/codegen-llvm/simd/simd-wide-sum.rs
new file mode 100644
index 00000000000..95117b2c748
--- /dev/null
+++ b/tests/codegen-llvm/simd/simd-wide-sum.rs
@@ -0,0 +1,59 @@
+//@ revisions: llvm mir-opt3
+//@ compile-flags: -C opt-level=3 -Z merge-functions=disabled
+//@ edition: 2021
+//@ only-x86_64
+//@ [mir-opt3]compile-flags: -Zmir-opt-level=3
+//@ [mir-opt3]build-pass
+
+// mir-opt3 is a regression test for https://github.com/rust-lang/rust/issues/98016
+
+#![crate_type = "lib"]
+#![feature(portable_simd)]
+
+use std::simd::prelude::*;
+const N: usize = 16;
+
+#[no_mangle]
+// CHECK-LABEL: @wider_reduce_simd
+pub fn wider_reduce_simd(x: Simd<u8, N>) -> u16 {
+    // CHECK: zext <16 x i8>
+    // CHECK-SAME: to <16 x i16>
+    // CHECK: call i16 @llvm.vector.reduce.add.v16i16(<16 x i16>
+    let x: Simd<u16, N> = x.cast();
+    x.reduce_sum()
+}
+
+#[no_mangle]
+// CHECK-LABEL: @wider_reduce_loop
+pub fn wider_reduce_loop(x: Simd<u8, N>) -> u16 {
+    // CHECK: zext <16 x i8>
+    // CHECK-SAME: to <16 x i16>
+    // CHECK: call i16 @llvm.vector.reduce.add.v16i16(<16 x i16>
+    let mut sum = 0_u16;
+    for i in 0..N {
+        sum += u16::from(x[i]);
+    }
+    sum
+}
+
+#[no_mangle]
+// CHECK-LABEL: @wider_reduce_iter
+pub fn wider_reduce_iter(x: Simd<u8, N>) -> u16 {
+    // CHECK: zext <16 x i8>
+    // CHECK-SAME: to <16 x i16>
+    // CHECK: call i16 @llvm.vector.reduce.add.v16i16(<16 x i16>
+    x.as_array().iter().copied().map(u16::from).sum()
+}
+
+// This iterator one is the most interesting, as it's the one
+// which used to not auto-vectorize due to a suboptimality in the
+// `<array::IntoIter as Iterator>::fold` implementation.
+
+#[no_mangle]
+// CHECK-LABEL: @wider_reduce_into_iter
+pub fn wider_reduce_into_iter(x: Simd<u8, N>) -> u16 {
+    // CHECK: zext <16 x i8>
+    // CHECK-SAME: to <16 x i16>
+    // CHECK: call i16 @llvm.vector.reduce.add.v16i16(<16 x i16>
+    x.to_array().into_iter().map(u16::from).sum()
+}