diff options
Diffstat (limited to 'src/Sema.zig')
| -rw-r--r-- | src/Sema.zig | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/Sema.zig b/src/Sema.zig index 2b1e31017b..f852710b95 100644 --- a/src/Sema.zig +++ b/src/Sema.zig @@ -4624,6 +4624,8 @@ fn validateUnionInit( // If the union is comptime, we want `first_block_index` // to point at %c so that the bitcast becomes the last instruction in the block. // + // Store instruction may be missing; if field type has only one possible value, this case is handled below. + // // In the case of a comptime-known pointer to a union, the // the field_ptr instruction is missing, so we have to pattern-match // based only on the store instructions. @@ -4634,7 +4636,10 @@ fn validateUnionInit( var init_val: ?Value = null; while (block_index > 0) : (block_index -= 1) { const store_inst = block.instructions.items[block_index]; - if (store_inst.toRef() == field_ptr_ref) break; + if (store_inst.toRef() == field_ptr_ref) { + first_block_index = block_index; + break; + } switch (air_tags[@intFromEnum(store_inst)]) { .store, .store_safe => {}, else => continue, @@ -4659,6 +4664,11 @@ fn validateUnionInit( const tag_ty = union_ty.unionTagTypeHypothetical(mod); const tag_val = try mod.enumValueFieldIndex(tag_ty, field_index); + const field_type = union_ty.unionFieldType(tag_val, mod).?; + + if (try sema.typeHasOnePossibleValue(field_type)) |field_only_value| { + init_val = field_only_value; + } if (init_val) |val| { // Our task is to delete all the `field_ptr` and `store` instructions, and insert |