add behavior test for comptime pointer casting

comptime `@ptrCast` a subset of an array, then write through it

closes #2444

3 files changed, 15 insertions, 0 deletions

diff --git a/test/behavior/array.zig b/test/behavior/array.zig
index 2f426bf5bf..52a4d7512a 100644
--- a/test/behavior/array.zig
+++ b/test/behavior/array.zig
@@ -61,6 +61,7 @@ test "array concat with undefined" {
 }
 
 test "array concat with tuple" {
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
 
diff --git a/test/behavior/bugs/12571.zig b/test/behavior/bugs/12571.zig
index 4338051b18..ace1e93b3f 100644
--- a/test/behavior/bugs/12571.zig
+++ b/test/behavior/bugs/12571.zig
@@ -14,6 +14,7 @@ const Entry = packed struct {
 test {
     if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
 
     const frame = Frame{ .num = 0x7FDE };
     var entry = Entry{ .other = 0, .frame = .{ .num = 0xFFFFF } };
diff --git a/test/behavior/ptrcast.zig b/test/behavior/ptrcast.zig
index e2d33f898c..0a983f82c6 100644
--- a/test/behavior/ptrcast.zig
+++ b/test/behavior/ptrcast.zig
@@ -257,3 +257,16 @@ test "@ptrCast slice to slice" {
     try expect(buf[1] == 42);
     try expect(alias.len == 4);
 }
+
+test "comptime @ptrCast a subset of an array, then write through it" {
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+
+    comptime {
+        var buff: [16]u8 align(4) = undefined;
+        const len_bytes = @ptrCast(*u32, &buff);
+        len_bytes.* = 16;
+        std.mem.copy(u8, buff[4..], "abcdef");
+    }
+}