[clang] [llvm] [SPIR-V] Implement SPV_KHR_untyped_pointers extension (PR #201233)

[Dmitry Sidorov via llvm-commits]

MrSidims wrote:

> thanks, please ping me for final approval once all feedback has been addressed/replied to

@sarnex thanks for review! I actually addressed all of the comments, but was caught mid-flight answering them by the regression reported in pre-commit and started working on https://github.com/llvm/llvm-project/pull/214240 :) apologies for the confusion

https://github.com/llvm/llvm-project/pull/201233