[clang] [X86][Clang] allow CRC32 intrinsics to be used in constexp (PR #173908)

[Simon Pilgrim via cfe-commits]

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@@ -138,3 +138,30 @@ unsigned long long test_mm_crc32_u64(unsigned long long CRC, unsigned long long
   return _mm_crc32_u64(CRC, V);
 }
 #endif
+
+#if defined(__cplusplus) && (__cplusplus >= 201103L)
+TEST_CONSTEXPR(_mm_crc32_u8(0x02a24bf8, 0xba) == 0xa042cf00);
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RKSimon wrote:

(style) Put these below the corresponding main test - _mm_crc32_u8 etc. - see other TEST_CONSTEXPR usaes for examples

https://github.com/llvm/llvm-project/pull/173908