Add regression test for option initialization

Author: oli-obk

tests/codegen/repeat-init.rs

@@ -0,0 +1,80 @@
+//@ compile-flags: -O -Z randomize-layout=no
+//@ only-x86_64
+#![crate_type = "lib"]
+
+extern crate core;
+
+use core::num::NonZero;
+use core::option::Option;
+
+const N: usize = 100;
+
+// CHECK-LABEL: @u8_init
+#[no_mangle]
+pub fn u8_init() -> [u8; N] {
+    // CHECK-NOT: select
+    // CHECK-NOT: br
+    // CHECK-NOT: switch
+    // CHECK-NOT: icmp
+    // CHECK: llvm.memset.p0
+    [0; N]
+}
+
+// CHECK-LABEL: @u8_init_ones
+#[no_mangle]
+pub fn u8_init_ones() -> [u8; N] {
+    // CHECK-NOT: select
+    // CHECK-NOT: br
+    // CHECK-NOT: switch
+    // CHECK-NOT: icmp
+    // CHECK: llvm.memset.p0
+    [1; N]
+}
+
+// CHECK-LABEL: @u16_init
+#[no_mangle]
+pub fn u16_init() -> [u16; N] {
+    // CHECK-NOT: select
+    // CHECK-NOT: br
+    // CHECK-NOT: switch
+    // CHECK-NOT: icmp
+    // CHECK: llvm.memset.p0
+    [0; N]
+}
+
+// This can't be helped
+// CHECK-LABEL: @u16_init_ones
+#[no_mangle]
+pub fn u16_init_ones() -> [u16; N] {
+    // CHECK-NOT: select
+    // CHECK-NOT: br
+    // CHECK-NOT: switch
+    // CHECK: getelementptr
+    // CHECK-NOT: llvm.memset.p0
+    [1; N]
+}
+
+// FIXME: The two bytes of the u16 are the same, so we should
+// just use memset, too.
+// CHECK-LABEL: @u16_init_one_bytes
+#[no_mangle]
+pub fn u16_init_one_bytes() -> [u16; N] {
+    // CHECK-NOT: select
+    // CHECK-NOT: br
+    // CHECK-NOT: switch
+    // CHECK-NOT: icmp
+    // CHECK: llvm.memset.p0
+    [u16::from_be_bytes([1, 1]); N]
+}
+
+// FIXME: undef bytes can just be initialized with the same value as the
+// defined bytes, if the defines bytes are all the same.
+// CHECK-LABEL: @option_none_init
+#[no_mangle]
+pub fn option_none_init() -> [Option<u8>; N] {
+    // CHECK-NOT: select
+    // CHECK: br
+    // CHECK-NOT: switch
+    // CHECK: icmp
+    [None; N]
+}