Use this to remove a linear scan from CodeGenProcModel::hasReadOfWrite.
This reduces build time of RISCVGenSubtargetInfo.inc on by machine from
~6 seconds to ~3 seconds.
2 of the 3 callers of each of these already had a reference they
converted to index. Use that reference and make the one caller
that only has an index responsible for looking up the reference from it.
Use this to improve performance of SubtargetEmitter::findWriteResources
and SubtargetEmitter::findReadAdvance. Now we can do a map lookup
instead of a linear search through all WriteRes/ReadAdvance records.
This reduces the build time of RISCVGenSubtargetInfo.inc on my
machine from 43 seconds to 10 seconds.
The function called find_if and converted the iterator to an index.
The caller then had to check the index being non-zero to know if the
find succeeded.
Seems better to just do the find and distance in the caller.
SubtargetEmitter::GenSchedClassTables takes a CodeGenProcModel, but
calls hasReadOfWrite which loops over all ProcModels. We move
hasReadOfWrite to CodeGenProcModel and remove the loop over all
ProcModels. This leads to a 144% speedup on the RISC-V backend of our
downstream.
Refactor of the llvm-tblgen source into:
- a "Basic" library, which contains the bare minimum utilities to build
`llvm-min-tablegen`
- a "Common" library which contains all of the helpers for TableGen
backends. Such helpers can be shared by more than one backend, and even
unit tested (e.g. CodeExpander is, maybe we can add more over time)
Fixes#80647
