[llvm] [AMDGPU] BackOffBarrier feature added to gfx1250; Removed incorrect "DS Store drain" check. (PR #179818)

[Sameer Sahasrabuddhe via llvm-commits]

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@@ -1941,6 +1941,7 @@ def FeatureISAVersion12 : FeatureSet<
 def FeatureISAVersion12_50_Common : FeatureSet<
   [FeatureGFX12,
    FeatureGFX1250Insts,
+   FeatureBackOffBarrier,
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ssahasra wrote:

This looks like a separate change. If I am understanding correctly, the observable change is that when compiling for GFX1250, we should not see the extra waits. Digging around in git history, it seems like these waits were first introduced in commit 7f97ac94f713b. At least the tests introduced in that commit should be run for GFX1250 to demonstrate the effect of adding this feature.

https://github.com/llvm/llvm-project/pull/179818