5774e068b7
Previously, the block successor accumulation and the blockparam branch arg setup were decoupled. The lowering backend implicitly specified the order of successor edges via its `MachTerminator` enum on the last instruction in the block, while the `Lower` toplevel machine-independent driver set up blockparam branch args in the edge order seen in CLIF. In some cases, these orders did not match -- for example, when the conditional branch depended on an FP condition that was implemented by swapping taken/not-taken edges and inverting the condition code. This PR refactors the successor handling to be centralized in `Lower` rather than flow through the terminator `MachInst`, and adds a successor block and its blockparam args at the same time, ensuring the orders match.
This crate contains the core Cranelift code generator. It translates code from an intermediate representation into executable machine code.