[Headers][X86] Allow _mm512_set1_epi32/64 intrinsics to be used in constexpr (#152674)

Pulled out of #152288 as I need this to proceed with several other patches

Author: RKSimon

clang/lib/Headers/avx512fintrin.h

@@ -314,7 +314,7 @@ _mm512_set1_epi16(short __w)
     __w, __w, __w, __w, __w, __w, __w, __w };
 }
 
-static __inline __m512i __DEFAULT_FN_ATTRS512
+static __inline __m512i __DEFAULT_FN_ATTRS512_CONSTEXPR
 _mm512_set1_epi32(int __s)
 {
   return __extension__ (__m512i)(__v16si){
@@ -330,7 +330,7 @@ _mm512_maskz_set1_epi32(__mmask16 __M, int __A)
                                              (__v16si)_mm512_setzero_si512());
 }
 
-static __inline __m512i __DEFAULT_FN_ATTRS512
+static __inline __m512i __DEFAULT_FN_ATTRS512_CONSTEXPR
 _mm512_set1_epi64(long long __d)
 {
   return __extension__(__m512i)(__v8di){ __d, __d, __d, __d, __d, __d, __d, __d };

clang/test/CodeGen/X86/avx512f-builtins.c

@@ -9062,6 +9062,36 @@ __m512i test_mm512_set1_epi16(short d)
   return _mm512_set1_epi16(d);
 }
 
+__m512i test_mm512_set1_epi32(int d)
+{
+  // CHECK-LABEL: test_mm512_set1_epi32
+  // CHECK: insertelement <16 x i32> {{.*}}, i32 0
+  // CHECK: insertelement <16 x i32> {{.*}}, i32 1
+  // CHECK: insertelement <16 x i32> {{.*}}, i32 2
+  // CHECK: insertelement <16 x i32> {{.*}}, i32 3
+  // CHECK: insertelement <16 x i32> {{.*}}, i32 4
+  // CHECK: insertelement <16 x i32> {{.*}}, i32 5
+  // CHECK: insertelement <16 x i32> {{.*}}, i32 6
+  // CHECK: insertelement <16 x i32> {{.*}}, i32 15
+  return _mm512_set1_epi32(d);
+}
+TEST_CONSTEXPR(match_v16si(_mm512_set1_epi32(99), 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99));
+
+__m512i test_mm512_set1_epi64(long long d)
+{
+  // CHECK-LABEL: test_mm512_set1_epi64
+  // CHECK: insertelement <8 x i64> {{.*}}, i32 0
+  // CHECK: insertelement <8 x i64> {{.*}}, i32 1
+  // CHECK: insertelement <8 x i64> {{.*}}, i32 2
+  // CHECK: insertelement <8 x i64> {{.*}}, i32 3
+  // CHECK: insertelement <8 x i64> {{.*}}, i32 4
+  // CHECK: insertelement <8 x i64> {{.*}}, i32 5
+  // CHECK: insertelement <8 x i64> {{.*}}, i32 6
+  // CHECK: insertelement <8 x i64> {{.*}}, i32 7
+  return _mm512_set1_epi64(d);
+}
+TEST_CONSTEXPR(match_v8di(_mm512_set1_epi64(-42), -42, -42, -42, -42, -42, -42, -42, -42));
+
 __m512i test_mm512_set4_epi32 (int __A, int __B, int __C, int __D)
 {
   // CHECK-LABEL: test_mm512_set4_epi32