[clang] [Headers][X86] Enable constexpr handling for pmulhw/pmulhuw intrinsics (PR #152540)

[Phoebe Wang via cfe-commits]

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@@ -940,18 +940,21 @@ __m128i test_mm_mulhi_epi16(__m128i A, __m128i B) {
   // CHECK: call <8 x i16> @llvm.x86.sse2.pmulh.w(<8 x i16> %{{.*}}, <8 x i16> %{{.*}})
   return _mm_mulhi_epi16(A, B);
 }
+TEST_CONSTEXPR(match_v8hi(_mm_mulhi_epi16((__m128i)(__v8hi){+1, -2, +3, -4, +5, -6, +7, -8}, (__m128i)(__v8hi){-16, -14, +12, +10, -8, +6, -4, +2}), -1, 0, 0, -1, -1, -1, -1, -1));
 
 __m128i test_mm_mulhi_epu16(__m128i A, __m128i B) {
   // CHECK-LABEL: test_mm_mulhi_epu16
   // CHECK: call <8 x i16> @llvm.x86.sse2.pmulhu.w(<8 x i16> %{{.*}}, <8 x i16> %{{.*}})
   return _mm_mulhi_epu16(A, B);
 }
+TEST_CONSTEXPR(match_v8hi(_mm_mulhi_epu16((__m128i)(__v8hi){+1, -2, +3, -4, +5, -6, +7, -8}, (__m128i)(__v8hi){-16, -14, +12, +10, -8, +6, -4, +2}), 0, -16, 0, 9, 4, 5, 6, 1));
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phoebewang wrote:

ditto.

https://github.com/llvm/llvm-project/pull/152540