[clang] [llvm] [HLSL][SPIRV][DXIL] Implement `WaveActiveSum` intrinsic (PR #112400)

[Justin Bogner via cfe-commits]

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@@ -2217,6 +2217,105 @@ __attribute__((convergent)) double3 WaveReadLaneAt(double3, int32_t);
 _HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_read_lane_at)
 __attribute__((convergent)) double4 WaveReadLaneAt(double4, int32_t);
 
+//===----------------------------------------------------------------------===//
+// WaveActiveSum builtins
+//===----------------------------------------------------------------------===//
+
+_HLSL_16BIT_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_active_sum)
+__attribute((convergent)) half WaveActiveSum(half);
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bogner wrote:

Please use the `__attribute__((convergent))` spelling to be consistent with the rest of the file.

https://github.com/llvm/llvm-project/pull/112400