54f074e507
* Re-introduce optional dedicated scratch registers Dedicated scratch registers used for resolving move cycles were removed in #51 and replaced with an algorithm to automatically allocate a scratch register as needed. However in many cases, a client will already have a non-allocatable scratch register available for things like extended jumps (see #91). It makes sense to re-use this register for regalloc than potentially spilling an existing register. * Clarify comment
regalloc2: another register allocator
This is a register allocator that started life as, and is about 50% still, a port of IonMonkey's backtracking register allocator to Rust. In many regards, it has been generalized, optimized, and improved since the initial port, and now supports both SSA and non-SSA use-cases. (However, non-SSA should be considered deprecated; we want to move to SSA-only in the future, to enable some performance improvements. See #4.)
In addition, it contains substantial amounts of testing infrastructure (fuzzing harnesses and checkers) that does not exist in the original IonMonkey allocator.
See the design overview for (much!) more detail on how the allocator works.
License
This crate is licensed under the Apache 2.0 License with LLVM
Exception. This license text can be found in the file LICENSE.
Parts of the code are derived from regalloc.rs: in particular,
src/checker.rs and src/domtree.rs. This crate has the same license
as regalloc.rs, so the license on these files does not differ.