From 6b9f7e26c9e43700225b7c2479305015df75a2b9 Mon Sep 17 00:00:00 2001
From: Bogdan Romanyuk <wrongnull@gmail.com>
Date: Thu, 9 Nov 2023 15:01:59 +0300
Subject: [PATCH] preserve 'undefined' in @bitCast

---
 src/Sema.zig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/Sema.zig b/src/Sema.zig
index f79f29dc0c..5827f22dd4 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -30719,6 +30719,8 @@ fn bitCast(
     }
 
     if (try sema.resolveValue(inst)) |val| {
+        if (val.isUndef(mod))
+            return mod.undefRef(dest_ty);
         if (try sema.bitCastVal(block, inst_src, val, old_ty, dest_ty, 0)) |result_val| {
             return Air.internedToRef(result_val.toIntern());
         }