[llvm] [SPIR-V] Enable structurizer for kernel environment (PR #166079)

[Dmitry Sidorov via llvm-commits]

MrSidims wrote:

Closing in favor of https://github.com/KhronosGroup/SPIRV-Registry/blob/main/extensions/INTEL/SPV_INTEL_unstructured_loop_controls.asciidoc implementation

https://github.com/llvm/llvm-project/pull/166079