[llvm] [GlobalISel] Compact failure targets in large match tables (PR #202642)

[David Zbarsky via llvm-commits]

dzbarsky wrote:

> This seems to implement two largely unrelated changes. The in-opcode root numbers and the relative references. These can be separated. And the first one doesn't really seem like something that should be using after the fact compaction and can just be directly emitted that way.

Thanks, agreed. I split the relative failure-target encoding into #202642 and moved the root-operand opcodes into #210562. LLTOperandMatcher, RegisterBankOperandMatcher, and CopyRenderer now emit operand indices 0–8 directly; larger indices and variadic copies retain the ULEB128 encoding.

https://github.com/llvm/llvm-project/pull/202642