[clang] [Clang][X86] Add tests for AVX512 integer comparison intrinsics to be used in constexpr (PR #169452)

[Simon Pilgrim via cfe-commits]

================
@@ -645,20 +645,123 @@ __mmask16 test_mm_cmp_epi8_mask(__m128i __a, __m128i __b) {
   return (__mmask16)_mm_cmp_epi8_mask(__a, __b, 0);
 }
 
+// cmpeq tests
 TEST_CONSTEXPR(_mm_cmpeq_epi8_mask(
-    ((__m128i)(__v16qi){5, 3, 7, 2, 9, 3, 7, 1, 5, 4, 8, 2, 9, 6, 7, 5}),
-    ((__m128i)(__v16qi){5, 2, 7, 3, 9, 4, 6, 1, 5, 3, 8, 1, 9, 5, 7, 5})
-) == (__mmask16)0xd595);
+    ((__m128i)(__v16qi){0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}),
+    ((__m128i)(__v16qi){0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0})
+) == (__mmask16)0xffff);
+
+TEST_CONSTEXPR(_mm_cmpeq_epi8_mask(
+    ((__m128i)(__v16qi){1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}),
+    ((__m128i)(__v16qi){1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1})
+) == (__mmask16)0xffff);
+
+TEST_CONSTEXPR(_mm_cmpeq_epi8_mask(
+    ((__m128i)(__v16qi){127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127}),
+    ((__m128i)(__v16qi){-128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128})
+) == (__mmask16)0x0000);
+
+TEST_CONSTEXPR(_mm_cmpeq_epi8_mask(
+    ((__m128i)(__v16qi){-31, 90, -66, 3, 27, -22, -64, 111, -87, 105, -19, 0, 26, -111, 24, -72}),
+    ((__m128i)(__v16qi){-84, -98, 20, -83, -98, 80, -46, -9, 22, -120, -123, 53, 117, -85, 50, 94})
+) == (__mmask16)0x0000);
+
----------------
RKSimon wrote:

You need _mm_mask_cmpeq_epi8_mask (et al) test coverage as well

https://github.com/llvm/llvm-project/pull/169452