[llvm] [AMDGPU] Add target feature require-naturally-aligned-buffer-access (PR #115479)

[Piotr Sobczak via llvm-commits]

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@@ -119,6 +119,12 @@ def FeatureUnalignedDSAccess : SubtargetFeature<"unaligned-ds-access",
   "Hardware supports unaligned local and region loads and stores"
 >;
 
+def FeatureRequireNaturallyAlignedBufferAccess : SubtargetFeature<"require-naturally-aligned-buffer-access",
+  "RequireNaturallyAlignedBufferAccess",
+  "true",
+  "Requires natural alignment of buffer accesses"
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piotrAMD wrote:

Maybe defining the new feature with 'alignment' in its name is unfortunate. This is really about extra out-of-bounds guarantees that are normally not required.
I will add some more describing text here, similar to what I added in the comment in SIISelLowering.cpp.

https://github.com/llvm/llvm-project/pull/115479