[clang] [llvm] [SPIRV][HLSL] Add lowering of `rsqrt` to SPIRV (PR #95849)

[Farzon Lotfi via cfe-commits]

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@@ -62,4 +62,5 @@ let TargetPrefix = "spv" in {
   def int_spv_any : DefaultAttrsIntrinsic<[llvm_i1_ty], [llvm_any_ty]>;
   def int_spv_lerp : Intrinsic<[LLVMMatchType<0>], [llvm_anyfloat_ty, LLVMMatchType<0>,LLVMMatchType<0>], 
     [IntrNoMem, IntrWillReturn] >;
+  def int_spv_rsqrt : DefaultAttrsIntrinsic<[LLVMMatchType<0>], [llvm_anyfloat_ty]>;
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farzonl wrote:

We need a test for this.  Can you add a spirv target to https://github.com/llvm/llvm-project/blob/117921e071a353edbd27f08456ec27ea98ecdb8c/clang/test/CodeGenHLSL/builtins/rsqrt.hlsl

https://github.com/llvm/llvm-project/pull/95849