fix comptime pointer reinterpretation array index offset

closes #1835

2 files changed, 18 insertions, 0 deletions

diff --git a/test/behavior.zig b/test/behavior.zig
index 499c20ee20..e32063dec8 100644
--- a/test/behavior.zig
+++ b/test/behavior.zig
@@ -52,6 +52,7 @@ comptime {
     _ = @import("cases/optional.zig");
     _ = @import("cases/pointers.zig");
     _ = @import("cases/popcount.zig");
+    _ = @import("cases/ptrcast.zig");
     _ = @import("cases/pub_enum/index.zig");
     _ = @import("cases/ref_var_in_if_after_if_2nd_switch_prong.zig");
     _ = @import("cases/reflection.zig");
diff --git a/test/cases/ptrcast.zig b/test/cases/ptrcast.zig
new file mode 100644
index 0000000000..071087c5c4
--- /dev/null
+++ b/test/cases/ptrcast.zig
@@ -0,0 +1,17 @@
+const builtin = @import("builtin");
+const std = @import("std");
+const assertOrPanic = std.debug.assertOrPanic;
+
+test "reinterpret bytes as integer with nonzero offset" {
+    testReinterpretBytesAsInteger();
+    comptime testReinterpretBytesAsInteger();
+}
+
+fn testReinterpretBytesAsInteger() void {
+    const bytes = "\x12\x34\x56\x78\xab";
+    const expected = switch (builtin.endian) {
+        builtin.Endian.Little => 0xab785634,
+        builtin.Endian.Big => 0x345678ab,
+    };
+    assertOrPanic(@ptrCast(*align(1) const u32, bytes[1..5].ptr).* == expected);
+}