[clang] [CIR][X86] Add support for kunpck builtins (PR #168757)

[Andy Kaylor via cfe-commits]

================
@@ -77,3 +77,27 @@ __m512i test_mm512_undefined_epi32(void) {
   // OGCG: ret <8 x i64> zeroinitializer
   return _mm512_undefined_epi32();
 }
+
+__mmask16 test_mm512_kunpackb(__mmask16 A, __mmask16 B) {
+  // CIR-LABEL: test_mm512_kunpackb
----------------
andykaylor wrote:

For CIR you need to check what's generated for the wrapper function. In this case, `_mm512_kunpackb`

https://github.com/llvm/llvm-project/pull/168757