[libclc] libclc: Update atanpi (PR #188424)

[Wenju He via cfe-commits]

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@@ -20,6 +20,17 @@ __clc_atan_reduced(__CLC_FLOATN v) {
   return z;
 }
 
+_CLC_DEF _CLC_OVERLOAD _CLC_CONST __CLC_FLOATN
+__clc_atanpi_reduced(__CLC_FLOATN v) {
+  __CLC_GENTYPE t = v * v;
+  __CLC_GENTYPE z = __clc_mad(t, __clc_mad(t, __clc_mad(t, __clc_mad(t,
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wenju-he wrote:

there is a small inconsistency __CLC_GENTYPE vs __CLC_FLOATN 

https://github.com/llvm/llvm-project/pull/188424