[llvm] [SPIRV] Addition of @llvm.lround.* and @llvm.llround.* intrinsic (PR #129240)

[Marcos Maronas via llvm-commits]

================
@@ -0,0 +1,106 @@
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv64-unknown-unknown %s -o - | FileCheck %s
----------------
maarquitos14 wrote:

I asked Google folks about that a while ago, this was their response:
```
To understand this part, we must look at the DXIL/HLSL triple:
HLSL uses the OS part to define the shader model, and the Env to define
the shader type. Example:

  - dxil-pc-shadermodel6.6-pixel
  - dxil-pc-shadermodel6.5-compute

So to have a similar model, we used the OS part for vulkan:
  - spirv-unknown-vulkan1.3-pixel
  - spirv-unknown-vulkan1.3-compute

If you switch vulkan to the environment, we would need to move the
pixel/compute/library/vertex to another part.
```

Regarding OpenCL, it was introduced as an environment for something completely unrelated to SPIRV.

https://github.com/llvm/llvm-project/pull/129240