base: change bitunion default constructor to default
Current implementation prevents customers from performing zero
initialize on BitUnion class. Customers would get unexpected results
when writing `BitUnion{}`. Changing the default constructor to default
can solve this issue.
After changing the default constructor, the test failed with unused
variable. I also change one with zero initializer and make the other
with maybe_unused label.
```
tests/build/ARM/base/bitunion.test.cc:133:14: error: 'emptySixteen' defined but not used [-Werror=unused-variable]
133 | EmptySixteen emptySixteen;
| ^~~~~~~~~~~~
tests/build/ARM/base/bitunion.test.cc:132:16: error: 'emptyThirtyTwo' defined but not used [-Werror=unused-variable]
132 | EmptyThirtyTwo emptyThirtyTwo;
| ^~~~~~~~~~~~~~
```
Change-Id: Icbed36b3fa6751cbda63e84443eaab6d865d9bd6
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57730
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
2 files changed
