[clang] [Headers][X86] Allow pmuludq/pmuldq to be used in constexpr (PR #153293)

[Simon Pilgrim via cfe-commits]

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@@ -925,6 +925,7 @@ __m128i test_mm_mul_epu32(__m128i A, __m128i B) {
   // CHECK: mul <2 x i64> %{{.*}}, %{{.*}}
   return _mm_mul_epu32(A, B);
 }
+TEST_CONSTEXPR(match_v8hi(_mm_mul_epu32((__m128i)(__v8hi){+1, -2, +3, -4, +5, -6, +7, -8}, (__m128i)(__v8hi){-16, -14, +12, +10, -8, +6, -4, +2}), -16, 18, 11, -15, -40, 82, -50, 6));
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RKSimon wrote:

why are you matching with a <8  x i16>? match_m128i / match_v2di seems better options

https://github.com/llvm/llvm-project/pull/153293