Integrate LLVM at llvm/llvm-project@2c440232e261

Updates LLVM usage to match
[2c440232e261](https://github.com/llvm/llvm-project/commit/2c440232e261)

PiperOrigin-RevId: 772680812

Merge pull request #2411 from hzeller:feature-20250616-update-rules-hdl

PiperOrigin-RevId: 772337451

Make benchmark_codegen_main mirror codegen_main more.

Rather than reimplementing lower-level codegen functions, we call the higher-level functions that take flag protos as inputs. This means we rebuild some options data structures, but that seems like a fair trade for making this easier to maintain.

This fixes some previously-broken benchmark targets in `//xls/modules/zstd`. Metadata was getting lost along the way.

PiperOrigin-RevId: 771259562

tools/gather_design_stats: fix cell count attributions and generate e…

Integrate LLVM at llvm/llvm-project@649020c68016

Updates LLVM usage to match
[649020c68016](https://github.com/llvm/llvm-project/commit/649020c68016)

PiperOrigin-RevId: 769431554

Integrate LLVM at llvm/llvm-project@56ebe64ce69a

Updates LLVM usage to match
[56ebe64ce69a](https://github.com/llvm/llvm-project/commit/56ebe64ce69a)

PiperOrigin-RevId: 768227995

Merge pull request #2311 from xlsynth:cdleary/2025-05-31-vast-flop-co…

Add feedbacks / phis from loop jump to loop begin.

Also fix unrolled loops with new FSM not to pipeline fully unrolled loops.

PiperOrigin-RevId: 766812271

Automated rollback of commit a2d15cc08711325180f2b17d8afa47d9f967fdfe.

PiperOrigin-RevId: 766363030

Let z3_ir_translator handle zero-width DynamicBitSlice

PiperOrigin-RevId: 765364231