[llvm] [AMDGPU] Fix LDS allocation granularity in occupancy computation for RDNA 2 (PR #219495)

[Matt Arsenault via llvm-commits]

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arsenm wrote:

These has*(ST) predicates should never be used, directly check the feature bit. 

It would also be better to properly track this instead of basing this on the only happens to be related instruction feature 

https://github.com/llvm/llvm-project/pull/219495