[clang] [llvm] [HLSL] Implement `WaveReadLaneAt` intrinsic (PR #111010)

[Chris B via cfe-commits]

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@@ -87,6 +87,7 @@ class CGHLSLRuntime {
   GENERATE_HLSL_INTRINSIC_FUNCTION(SDot, sdot)
   GENERATE_HLSL_INTRINSIC_FUNCTION(UDot, udot)
   GENERATE_HLSL_INTRINSIC_FUNCTION(WaveIsFirstLane, wave_is_first_lane)
+  GENERATE_HLSL_INTRINSIC_FUNCTION(WaveReadLaneAt, waveReadLaneAt)
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llvm-beanz wrote:

The equivalent AMD GPU intrinsic is named `int_amdgcn_readlane`, which translates to `llvm.amdgcn.readlane`. Having `dx.readlane` or `dx.wave.readlane` seems like a preferable naming approach.

https://github.com/llvm/llvm-project/pull/111010