[clang] [llvm] [HLSL] Adding HLSL `clip` function. (PR #114588)

[Finn Plummer via cfe-commits]

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@@ -770,6 +770,15 @@ def CheckAccessFullyMapped : DXILOp<71, checkAccessFullyMapped> {
   let stages = [Stages<DXIL1_0, [all_stages]>];
 }
 
+def Discard : DXILOp<82, discard> {
+  let Doc = "discard the current pixel";
+  let LLVMIntrinsic = int_dx_discard;
+  let arguments = [Int1Ty];
+  let result = VoidTy;
+  let stages = [Stages<DXIL1_0, [pixel]>];
+  let attributes = [Attributes<DXIL1_0, [ReadNone]>];
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inbelic wrote:

```suggestion
```
This attribute is not specified in `hctdb.py`.

https://github.com/llvm/llvm-project/pull/114588