[llvm] [SPIR-V] Lower llvm.x.with.overflow intrinsics (PR #95012)

[Michal Paszkowski via llvm-commits]

michalpaszkowski wrote:

The major (sole) role of the SPIRVPrepareFunctions pass is to prepare and expose all aggregate related instructions and intrinsics to SPIRVEmitIntrinsics pass where:
```
// This pass performs the following transformation on LLVM IR level required
// for the following translation to SPIR-V:
// - replaces direct usages of aggregate constants with target-specific
//   intrinsics;
// - replaces aggregates-related instructions (extract/insert, ld/st, etc)
//   with a target-specific intrinsics;
```

https://github.com/llvm/llvm-project/pull/95012