stage2 LLVM: Use a packed aggregate for union payload init

Without the packed qualifier, the type layout that we use to
initialize doesn't match the correct layout of the underlying
storage, causing corrupted data and past-the-end writes.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index a24c14c9c6..300a24280a 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -8897,7 +8897,7 @@ pub const FuncGen = struct {
             return union_llvm_ty.constInt(tag_int, .False);
         }
         assert(isByRef(union_ty));
-        // The llvm type of the alloca will the the named LLVM union type, which will not
+        // The llvm type of the alloca will be the named LLVM union type, and will not
         // necessarily match the format that we need, depending on which tag is active. We
         // must construct the correct unnamed struct type here and bitcast, in order to
         // then set the fields appropriately.
@@ -8922,7 +8922,7 @@ pub const FuncGen = struct {
                 const fields: [2]*llvm.Type = .{
                     field_llvm_ty, self.context.intType(8).arrayType(padding_len),
                 };
-                break :p self.context.structType(&fields, fields.len, .False);
+                break :p self.context.structType(&fields, fields.len, .True);
             };
             if (layout.tag_size == 0) {
                 const fields: [1]*llvm.Type = .{payload};