[clang] [llvm] [HLSL] Implement the `degrees` intrinsic (PR #111209)

[Sarah Spall via cfe-commits]

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@@ -2625,6 +2645,8 @@ bool SPIRVInstructionSelector::selectIntrinsic(Register ResVReg,
     return selectFmix(ResVReg, ResType, I);
   case Intrinsic::spv_length:
     return selectLength(ResVReg, ResType, I);
+  case Intrinsic::spv_degrees:
+    return selectDegrees(ResVReg, ResType, I);
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spall wrote:

Assuming it does take 1 operand, can you use selectExtInst here instead of a custom function? 

https://github.com/llvm/llvm-project/pull/111209