The isplit_lohi instruction breaks an integer into two halves. This will
typically be used to get the two halves of an `i64` value on 32-bit
CPUs.
The iconcat_lohi is the reverse operation. It reconstructs the `i64`
from the low and high bits.
It's not super fast to clone a function, but it is faster than
re-parsing the test case file it came from.
Some tests want to mutate the function, and there may be other tests in
the same script that need the original function.
We have multiple pre-computed constant hash tables that all use the same
quadratic probing algorithm.
Add a constant_hash Rust module to match the meta/constant_hash.py module.
Move the simple_hash() function into constant_hash. Its Python equivalent is in
the constant_hash.py module.
Rather than switching on instruction formats to discover the destination of a
branch, use the analyze_branch method which returns a BranchInfo enum with just
the relevant information.
This makes CFG algorithms independent of future instruction formats for
branches. Only analyze_branch needs to be updated when adding a new format.
