diff --git a/clang/include/clang/Basic/BuiltinsX86.td b/clang/include/clang/Basic/BuiltinsX86.td
index 500aa85fe5356..0b1c9b3dbfdc3 100644
--- a/clang/include/clang/Basic/BuiltinsX86.td
+++ b/clang/include/clang/Basic/BuiltinsX86.td
@@ -3193,31 +3193,31 @@ let Features = "avx512bw", Attributes = [NoThrow, Const, Constexpr] in {
   def kordi : X86Builtin<"unsigned long long int(unsigned long long int, unsigned long long int)">;
 }
 
-let Features = "avx512dq", Attributes = [NoThrow, Const] in {
+let Features = "avx512dq", Attributes = [NoThrow, Const, Constexpr] in {
   def kortestcqi : X86Builtin<"int(unsigned char, unsigned char)">;
   def kortestzqi : X86Builtin<"int(unsigned char, unsigned char)">;
 }
 
-let Features = "avx512f", Attributes = [NoThrow, Const] in {
+let Features = "avx512f", Attributes = [NoThrow, Const, Constexpr] in {
   def kortestchi : X86Builtin<"int(unsigned short, unsigned short)">;
   def kortestzhi : X86Builtin<"int(unsigned short, unsigned short)">;
 }
 
-let Features = "avx512bw", Attributes = [NoThrow, Const] in {
+let Features = "avx512bw", Attributes = [NoThrow, Const, Constexpr] in {
   def kortestcsi : X86Builtin<"int(unsigned int, unsigned int)">;
   def kortestzsi : X86Builtin<"int(unsigned int, unsigned int)">;
   def kortestcdi : X86Builtin<"int(unsigned long long int, unsigned long long int)">;
   def kortestzdi : X86Builtin<"int(unsigned long long int, unsigned long long int)">;
 }
 
-let Features = "avx512dq", Attributes = [NoThrow, Const] in {
+let Features = "avx512dq", Attributes = [NoThrow, Const, Constexpr] in {
   def ktestcqi : X86Builtin<"int(unsigned char, unsigned char)">;
   def ktestzqi : X86Builtin<"int(unsigned char, unsigned char)">;
   def ktestchi : X86Builtin<"int(unsigned short, unsigned short)">;
   def ktestzhi : X86Builtin<"int(unsigned short, unsigned short)">;
 }
 
-let Features = "avx512bw", Attributes = [NoThrow, Const] in {
+let Features = "avx512bw", Attributes = [NoThrow, Const, Constexpr] in {
   def ktestcsi : X86Builtin<"int(unsigned int, unsigned int)">;
   def ktestzsi : X86Builtin<"int(unsigned int, unsigned int)">;
   def ktestcdi : X86Builtin<"int(unsigned long long int, unsigned long long int)">;
diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
index ab6b3ed1be0aa..7b1f3c5a7189a 100644
--- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp
+++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
@@ -3792,6 +3792,42 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call,
           return Result;
         });
 
+  case clang::X86::BI__builtin_ia32_ktestcqi:
+  case clang::X86::BI__builtin_ia32_ktestchi:
+  case clang::X86::BI__builtin_ia32_ktestcsi:
+  case clang::X86::BI__builtin_ia32_ktestcdi:
+    return interp__builtin_elementwise_int_binop(
+        S, OpPC, Call, [](const APSInt &A, const APSInt &B) {
+          return APInt(sizeof(unsigned char) * 8, (~A & B) == 0);
+        });
+
+  case clang::X86::BI__builtin_ia32_ktestzqi:
+  case clang::X86::BI__builtin_ia32_ktestzhi:
+  case clang::X86::BI__builtin_ia32_ktestzsi:
+  case clang::X86::BI__builtin_ia32_ktestzdi:
+    return interp__builtin_elementwise_int_binop(
+        S, OpPC, Call, [](const APSInt &A, const APSInt &B) {
+          return APInt(sizeof(unsigned char) * 8, (A & B) == 0);
+        });
+
+  case clang::X86::BI__builtin_ia32_kortestcqi:
+  case clang::X86::BI__builtin_ia32_kortestchi:
+  case clang::X86::BI__builtin_ia32_kortestcsi:
+  case clang::X86::BI__builtin_ia32_kortestcdi:
+    return interp__builtin_elementwise_int_binop(
+        S, OpPC, Call, [](const APSInt &A, const APSInt &B) {
+          return APInt(sizeof(unsigned char) * 8, ~(A | B) == 0);
+        });
+
+  case clang::X86::BI__builtin_ia32_kortestzqi:
+  case clang::X86::BI__builtin_ia32_kortestzhi:
+  case clang::X86::BI__builtin_ia32_kortestzsi:
+  case clang::X86::BI__builtin_ia32_kortestzdi:
+    return interp__builtin_elementwise_int_binop(
+        S, OpPC, Call, [](const APSInt &A, const APSInt &B) {
+          return APInt(sizeof(unsigned char) * 8, (A | B) == 0);
+        });
+
   case clang::X86::BI__builtin_ia32_lzcnt_u16:
   case clang::X86::BI__builtin_ia32_lzcnt_u32:
   case clang::X86::BI__builtin_ia32_lzcnt_u64:
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index d0404b957ab03..2abc1c3b5f624 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -15614,6 +15614,54 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
     return Success(Val, E);
   }
 
+  case clang::X86::BI__builtin_ia32_ktestcqi:
+  case clang::X86::BI__builtin_ia32_ktestchi:
+  case clang::X86::BI__builtin_ia32_ktestcsi:
+  case clang::X86::BI__builtin_ia32_ktestcdi: {
+    APSInt A, B;
+    if (!EvaluateInteger(E->getArg(0), A, Info) ||
+        !EvaluateInteger(E->getArg(1), B, Info))
+      return false;
+
+    return Success((~A & B) == 0, E);
+  }
+
+  case clang::X86::BI__builtin_ia32_ktestzqi:
+  case clang::X86::BI__builtin_ia32_ktestzhi:
+  case clang::X86::BI__builtin_ia32_ktestzsi:
+  case clang::X86::BI__builtin_ia32_ktestzdi: {
+    APSInt A, B;
+    if (!EvaluateInteger(E->getArg(0), A, Info) ||
+        !EvaluateInteger(E->getArg(1), B, Info))
+      return false;
+
+    return Success((A & B) == 0, E);
+  }
+
+  case clang::X86::BI__builtin_ia32_kortestcqi:
+  case clang::X86::BI__builtin_ia32_kortestchi:
+  case clang::X86::BI__builtin_ia32_kortestcsi:
+  case clang::X86::BI__builtin_ia32_kortestcdi: {
+    APSInt A, B;
+    if (!EvaluateInteger(E->getArg(0), A, Info) ||
+        !EvaluateInteger(E->getArg(1), B, Info))
+      return false;
+
+    return Success(~(A | B) == 0, E);
+  }
+
+  case clang::X86::BI__builtin_ia32_kortestzqi:
+  case clang::X86::BI__builtin_ia32_kortestzhi:
+  case clang::X86::BI__builtin_ia32_kortestzsi:
+  case clang::X86::BI__builtin_ia32_kortestzdi: {
+    APSInt A, B;
+    if (!EvaluateInteger(E->getArg(0), A, Info) ||
+        !EvaluateInteger(E->getArg(1), B, Info))
+      return false;
+
+    return Success((A | B) == 0, E);
+  }
+
   case clang::X86::BI__builtin_ia32_lzcnt_u16:
   case clang::X86::BI__builtin_ia32_lzcnt_u32:
   case clang::X86::BI__builtin_ia32_lzcnt_u64: {
diff --git a/clang/lib/Headers/avx512bwintrin.h b/clang/lib/Headers/avx512bwintrin.h
index ac75b6ccde735..21915a4ec2934 100644
--- a/clang/lib/Headers/avx512bwintrin.h
+++ b/clang/lib/Headers/avx512bwintrin.h
@@ -92,69 +92,65 @@ _kxor_mask64(__mmask64 __A, __mmask64 __B) {
   return (__mmask64)__builtin_ia32_kxordi((__mmask64)__A, (__mmask64)__B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_kortestc_mask32_u8(__mmask32 __A, __mmask32 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_kortestc_mask32_u8(__mmask32 __A, __mmask32 __B) {
   return (unsigned char)__builtin_ia32_kortestcsi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_kortestz_mask32_u8(__mmask32 __A, __mmask32 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_kortestz_mask32_u8(__mmask32 __A, __mmask32 __B) {
   return (unsigned char)__builtin_ia32_kortestzsi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _kortest_mask32_u8(__mmask32 __A, __mmask32 __B, unsigned char *__C) {
   *__C = (unsigned char)__builtin_ia32_kortestcsi(__A, __B);
   return (unsigned char)__builtin_ia32_kortestzsi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _kortestc_mask64_u8(__mmask64 __A, __mmask64 __B) {
   return (unsigned char)__builtin_ia32_kortestcdi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _kortestz_mask64_u8(__mmask64 __A, __mmask64 __B) {
   return (unsigned char)__builtin_ia32_kortestzdi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _kortest_mask64_u8(__mmask64 __A, __mmask64 __B, unsigned char *__C) {
   *__C = (unsigned char)__builtin_ia32_kortestcdi(__A, __B);
   return (unsigned char)__builtin_ia32_kortestzdi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_ktestc_mask32_u8(__mmask32 __A, __mmask32 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_ktestc_mask32_u8(__mmask32 __A, __mmask32 __B) {
   return (unsigned char)__builtin_ia32_ktestcsi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_ktestz_mask32_u8(__mmask32 __A, __mmask32 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_ktestz_mask32_u8(__mmask32 __A, __mmask32 __B) {
   return (unsigned char)__builtin_ia32_ktestzsi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _ktest_mask32_u8(__mmask32 __A, __mmask32 __B, unsigned char *__C) {
   *__C = (unsigned char)__builtin_ia32_ktestcsi(__A, __B);
   return (unsigned char)__builtin_ia32_ktestzsi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _ktestc_mask64_u8(__mmask64 __A, __mmask64 __B) {
   return (unsigned char)__builtin_ia32_ktestcdi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _ktestz_mask64_u8(__mmask64 __A, __mmask64 __B) {
   return (unsigned char)__builtin_ia32_ktestzdi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _ktest_mask64_u8(__mmask64 __A, __mmask64 __B, unsigned char *__C) {
   *__C = (unsigned char)__builtin_ia32_ktestcdi(__A, __B);
   return (unsigned char)__builtin_ia32_ktestzdi(__A, __B);
diff --git a/clang/lib/Headers/avx512dqintrin.h b/clang/lib/Headers/avx512dqintrin.h
index fef1a2d64d538..29156e7e96434 100644
--- a/clang/lib/Headers/avx512dqintrin.h
+++ b/clang/lib/Headers/avx512dqintrin.h
@@ -59,55 +59,49 @@ _kxor_mask8(__mmask8 __A, __mmask8 __B) {
   return (__mmask8)__builtin_ia32_kxorqi((__mmask8)__A, (__mmask8)__B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_kortestc_mask8_u8(__mmask8 __A, __mmask8 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_kortestc_mask8_u8(__mmask8 __A, __mmask8 __B) {
   return (unsigned char)__builtin_ia32_kortestcqi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_kortestz_mask8_u8(__mmask8 __A, __mmask8 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_kortestz_mask8_u8(__mmask8 __A, __mmask8 __B) {
   return (unsigned char)__builtin_ia32_kortestzqi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _kortest_mask8_u8(__mmask8 __A, __mmask8 __B, unsigned char *__C) {
   *__C = (unsigned char)__builtin_ia32_kortestcqi(__A, __B);
   return (unsigned char)__builtin_ia32_kortestzqi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_ktestc_mask8_u8(__mmask8 __A, __mmask8 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_ktestc_mask8_u8(__mmask8 __A, __mmask8 __B) {
   return (unsigned char)__builtin_ia32_ktestcqi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_ktestz_mask8_u8(__mmask8 __A, __mmask8 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_ktestz_mask8_u8(__mmask8 __A, __mmask8 __B) {
   return (unsigned char)__builtin_ia32_ktestzqi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _ktest_mask8_u8(__mmask8 __A, __mmask8 __B, unsigned char *__C) {
   *__C = (unsigned char)__builtin_ia32_ktestcqi(__A, __B);
   return (unsigned char)__builtin_ia32_ktestzqi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_ktestc_mask16_u8(__mmask16 __A, __mmask16 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_ktestc_mask16_u8(__mmask16 __A, __mmask16 __B) {
   return (unsigned char)__builtin_ia32_ktestchi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_ktestz_mask16_u8(__mmask16 __A, __mmask16 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_ktestz_mask16_u8(__mmask16 __A, __mmask16 __B) {
   return (unsigned char)__builtin_ia32_ktestzhi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _ktest_mask16_u8(__mmask16 __A, __mmask16 __B, unsigned char *__C) {
   *__C = (unsigned char)__builtin_ia32_ktestchi(__A, __B);
   return (unsigned char)__builtin_ia32_ktestzhi(__A, __B);
diff --git a/clang/lib/Headers/avx512fintrin.h b/clang/lib/Headers/avx512fintrin.h
index 18c4a44a4c76e..aa77e270f99a1 100644
--- a/clang/lib/Headers/avx512fintrin.h
+++ b/clang/lib/Headers/avx512fintrin.h
@@ -8081,31 +8081,27 @@ _mm512_kor(__mmask16 __A, __mmask16 __B) {
   return (__mmask16) __builtin_ia32_korhi ((__mmask16) __A, (__mmask16) __B);
 }
 
-static __inline__ int __DEFAULT_FN_ATTRS
-_mm512_kortestc (__mmask16 __A, __mmask16 __B)
-{
+static __inline__ int __DEFAULT_FN_ATTRS_CONSTEXPR
+_mm512_kortestc(__mmask16 __A, __mmask16 __B) {
   return __builtin_ia32_kortestchi ((__mmask16) __A, (__mmask16) __B);
 }
 
-static __inline__ int __DEFAULT_FN_ATTRS
-_mm512_kortestz (__mmask16 __A, __mmask16 __B)
-{
+static __inline__ int __DEFAULT_FN_ATTRS_CONSTEXPR
+_mm512_kortestz(__mmask16 __A, __mmask16 __B) {
   return __builtin_ia32_kortestzhi ((__mmask16) __A, (__mmask16) __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_kortestc_mask16_u8(__mmask16 __A, __mmask16 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_kortestc_mask16_u8(__mmask16 __A, __mmask16 __B) {
   return (unsigned char)__builtin_ia32_kortestchi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-_kortestz_mask16_u8(__mmask16 __A, __mmask16 __B)
-{
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
+_kortestz_mask16_u8(__mmask16 __A, __mmask16 __B) {
   return (unsigned char)__builtin_ia32_kortestzhi(__A, __B);
 }
 
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
+static __inline__ unsigned char __DEFAULT_FN_ATTRS_CONSTEXPR
 _kortest_mask16_u8(__mmask16 __A, __mmask16 __B, unsigned char *__C) {
   *__C = (unsigned char)__builtin_ia32_kortestchi(__A, __B);
   return (unsigned char)__builtin_ia32_kortestzhi(__A, __B);
diff --git a/clang/test/CodeGen/X86/avx512bw-builtins.c b/clang/test/CodeGen/X86/avx512bw-builtins.c
index be2cd480f7558..d2f5da22cd07c 100644
--- a/clang/test/CodeGen/X86/avx512bw-builtins.c
+++ b/clang/test/CodeGen/X86/avx512bw-builtins.c
@@ -209,6 +209,10 @@ unsigned char test_kortestz_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m
                              _mm512_cmpneq_epu16_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_kortestz_mask32_u8(0x0000'0000, 0x0000'0000) == 1);
+TEST_CONSTEXPR(_kortestz_mask32_u8(0x0000'0000, 0x8000'0000) == 0);
+TEST_CONSTEXPR(_kortestz_mask32_u8(0x0123'4567, 0xFEDC'BA98) == 0);
+
 unsigned char test_kortestc_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_kortestc_mask32_u8
   // CHECK: [[LHS:%.*]] = bitcast i32 %{{.*}} to <32 x i1>
@@ -222,6 +226,10 @@ unsigned char test_kortestc_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m
                              _mm512_cmpneq_epu16_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_kortestc_mask32_u8(0x0000'0000, 0x0000'0000) == 0);
+TEST_CONSTEXPR(_kortestc_mask32_u8(0x0000'0000, 0x8000'0000) == 0);
+TEST_CONSTEXPR(_kortestc_mask32_u8(0x0123'4567, 0xFEDC'BA98) == 1);
+
 unsigned char test_kortest_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D, unsigned char *CF) {
   // CHECK-LABEL: test_kortest_mask32_u8
   // CHECK: [[LHS:%.*]] = bitcast i32 %{{.*}} to <32 x i1>
@@ -242,6 +250,30 @@ unsigned char test_kortest_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m5
                             _mm512_cmpneq_epu16_mask(__C, __D), CF);
 }
 
+// Test constexpr handling.
+#if defined(__cplusplus) && (__cplusplus >= 201103L)
+constexpr unsigned char
+test_kortest_mask32_u8(unsigned int A, unsigned int B) {
+  unsigned char all_ones{};
+  return (_kortest_mask32_u8(A, B, &all_ones) << 4) | all_ones;
+}
+
+void _kortest_mask32_u8() {
+  constexpr unsigned int A1 = 0x0000'0000;
+  constexpr unsigned int B1 = 0x0000'0000;
+  constexpr unsigned char expected_result_1 = 0x10;
+  static_assert(test_kortest_mask32_u8(A1, B1) == expected_result_1);
+  constexpr unsigned int A2 = 0x0000'0000;
+  constexpr unsigned int B2 = 0x8000'0000;
+  constexpr unsigned char expected_result_2 = 0x00;
+  static_assert(test_kortest_mask32_u8(A2, B2) == expected_result_2);
+  constexpr unsigned int A3 = 0x0123'4567;
+  constexpr unsigned int B3 = 0xFEDC'BA98;
+  constexpr unsigned char expected_result_3 = 0x01;
+  static_assert(test_kortest_mask32_u8(A3, B3) == expected_result_3);
+}
+#endif
+
 unsigned char test_kortestz_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_kortestz_mask64_u8
   // CHECK: [[LHS:%.*]] = bitcast i64 %{{.*}} to <64 x i1>
@@ -255,6 +287,10 @@ unsigned char test_kortestz_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m
                              _mm512_cmpneq_epu8_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_kortestz_mask64_u8(0x0000'0000'0000'0000, 0x0000'0000'0000'0000) == 1);
+TEST_CONSTEXPR(_kortestz_mask64_u8(0x0000'0000'0000'0000, 0x8000'0000'0000'0000) == 0);
+TEST_CONSTEXPR(_kortestz_mask64_u8(0x0123'4567'89AB'CDEF, 0xFEDC'BA98'7654'3210) == 0);
+
 unsigned char test_kortestc_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_kortestc_mask64_u8
   // CHECK: [[LHS:%.*]] = bitcast i64 %{{.*}} to <64 x i1>
@@ -268,6 +304,10 @@ unsigned char test_kortestc_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m
                              _mm512_cmpneq_epu8_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_kortestc_mask64_u8(0x0000'0000'0000'0000, 0x0000'0000'0000'0000) == 0);
+TEST_CONSTEXPR(_kortestc_mask64_u8(0x0023'4567'89AB'CDEF, 0xFEDC'BA98'7654'3210) == 0);
+TEST_CONSTEXPR(_kortestc_mask64_u8(0x0123'4567'89AB'CDEF, 0xFEDC'BA98'7654'3210) == 1);
+
 unsigned char test_kortest_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D, unsigned char *CF) {
   // CHECK-LABEL: test_kortest_mask64_u8
   // CHECK: [[LHS:%.*]] = bitcast i64 %{{.*}} to <64 x i1>
@@ -288,6 +328,30 @@ unsigned char test_kortest_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m5
                             _mm512_cmpneq_epu8_mask(__C, __D), CF);
 }
 
+// Test constexpr handling.
+#if defined(__cplusplus) && (__cplusplus >= 201103L)
+constexpr unsigned char
+test_kortest_mask64_u8(unsigned long long A, unsigned long long B) {
+  unsigned char all_ones{};
+  return (_kortest_mask64_u8(A, B, &all_ones) << 4) | all_ones;
+}
+
+void _kortest_mask64_u8() {
+  constexpr unsigned long long A1 = 0x0000'0000'0000'0000;
+  constexpr unsigned long long B1 = 0x0000'0000'0000'0000;
+  constexpr unsigned char expected_result_1 = 0x10;
+  static_assert(test_kortest_mask64_u8(A1, B1) == expected_result_1);
+  constexpr unsigned long long A2 = 0x0000'0000'0000'0000;
+  constexpr unsigned long long B2 = 0x8000'0000'0000'0000;
+  constexpr unsigned char expected_result_2 = 0x00;
+  static_assert(test_kortest_mask64_u8(A2, B2) == expected_result_2);
+  constexpr unsigned long long A3 = 0x0123'4567'89AB'CDEF;
+  constexpr unsigned long long B3 = 0xFEDC'BA98'7654'3210;
+  constexpr unsigned char expected_result_3 = 0x01;
+  static_assert(test_kortest_mask64_u8(A3, B3) == expected_result_3);
+}
+#endif
+
 unsigned char test_ktestz_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_ktestz_mask32_u8
   // CHECK: [[LHS:%.*]] = bitcast i32 %{{.*}} to <32 x i1>
@@ -298,6 +362,11 @@ unsigned char test_ktestz_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m51
                            _mm512_cmpneq_epu16_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_ktestz_mask32_u8(0x0000'0000, 0x0000'0000) == 1);
+TEST_CONSTEXPR(_ktestz_mask32_u8(0x0000'0000, 0x8000'0000) == 1);
+TEST_CONSTEXPR(_ktestz_mask32_u8(0xF000'0000, 0x8000'0000) == 0);
+TEST_CONSTEXPR(_ktestz_mask32_u8(0x0123'4567, 0x0123'4567) == 0);
+
 unsigned char test_ktestc_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_ktestc_mask32_u8
   // CHECK: [[LHS:%.*]] = bitcast i32 %{{.*}} to <32 x i1>
@@ -308,6 +377,11 @@ unsigned char test_ktestc_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m51
                            _mm512_cmpneq_epu16_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_ktestc_mask32_u8(0x0000'0000, 0x0000'0000) == 1);
+TEST_CONSTEXPR(_ktestc_mask32_u8(0x0000'0000, 0x8000'0000) == 0);
+TEST_CONSTEXPR(_ktestc_mask32_u8(0xF000'0000, 0x8000'0000) == 1);
+TEST_CONSTEXPR(_ktestc_mask32_u8(0x0123'4567, 0x0123'4567) == 1);
+
 unsigned char test_ktest_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D, unsigned char *CF) {
   // CHECK-LABEL: test_ktest_mask32_u8
   // CHECK: [[LHS:%.*]] = bitcast i32 %{{.*}} to <32 x i1>
@@ -322,6 +396,34 @@ unsigned char test_ktest_mask32_u8(__m512i __A, __m512i __B, __m512i __C, __m512
                           _mm512_cmpneq_epu16_mask(__C, __D), CF);
 }
 
+// Test constexpr handling.
+#if defined(__cplusplus) && (__cplusplus >= 201103L)
+constexpr unsigned char
+test_ktest_mask32_u8(unsigned int A, unsigned int B) {
+  unsigned char and_not{};
+  return (_ktest_mask32_u8(A, B, &and_not) << 4) | and_not;
+}
+
+void _ktest_mask32_u8() {
+  constexpr unsigned int A1 = 0x0000'0000;
+  constexpr unsigned int B1 = 0x0000'0000;
+  constexpr unsigned char expected_result_1 = 0x11;
+  static_assert(test_ktest_mask32_u8(A1, B1) == expected_result_1);
+  constexpr unsigned int A2 = 0x0000'0000;
+  constexpr unsigned int B2 = 0x8000'0000;
+  constexpr unsigned char expected_result_2 = 0x10;
+  static_assert(test_ktest_mask32_u8(A2, B2) == expected_result_2);
+  constexpr unsigned int A3 = 0xF000'0000;
+  constexpr unsigned int B3 = 0x8000'0000;
+  constexpr unsigned char expected_result_3 = 0x01;
+  static_assert(test_ktest_mask32_u8(A3, B3) == expected_result_3);
+  constexpr unsigned int A4 = 0x0123'4567;
+  constexpr unsigned int B4 = 0x0123'4567;
+  constexpr unsigned char expected_result_4 = 0x01;
+  static_assert(test_ktest_mask32_u8(A4, B4) == expected_result_4);
+}
+#endif
+
 unsigned char test_ktestz_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_ktestz_mask64_u8
   // CHECK: [[LHS:%.*]] = bitcast i64 %{{.*}} to <64 x i1>
@@ -332,6 +434,11 @@ unsigned char test_ktestz_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m51
                            _mm512_cmpneq_epu8_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_ktestz_mask64_u8(0x0000'0000'0000'0000, 0x0000'0000'0000'0000) == 1);
+TEST_CONSTEXPR(_ktestz_mask64_u8(0x0000'0000'0000'0000, 0x8000'0000'0000'0000) == 1);
+TEST_CONSTEXPR(_ktestz_mask64_u8(0xF000'0000'0000'0000, 0x8000'0000'0000'0000) == 0);
+TEST_CONSTEXPR(_ktestz_mask64_u8(0x0123'4567'89AB'CDEF, 0x0123'4567'89AB'CDEF) == 0);
+
 unsigned char test_ktestc_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_ktestc_mask64_u8
   // CHECK: [[LHS:%.*]] = bitcast i64 %{{.*}} to <64 x i1>
@@ -342,6 +449,11 @@ unsigned char test_ktestc_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m51
                            _mm512_cmpneq_epu8_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_ktestc_mask64_u8(0x0000'0000'0000'0000, 0x0000'0000'0000'0000) == 1);
+TEST_CONSTEXPR(_ktestc_mask64_u8(0x0000'0000'0000'0000, 0x8000'0000'0000'0000) == 0);
+TEST_CONSTEXPR(_ktestc_mask64_u8(0xF000'0000'0000'0000, 0x8000'0000'0000'0000) == 1);
+TEST_CONSTEXPR(_ktestc_mask64_u8(0x0123'4567'89AB'CDEF, 0x0123'4567'89AB'CDEF) == 1);
+
 unsigned char test_ktest_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D, unsigned char *CF) {
   // CHECK-LABEL: test_ktest_mask64_u8
   // CHECK: [[LHS:%.*]] = bitcast i64 %{{.*}} to <64 x i1>
@@ -356,6 +468,34 @@ unsigned char test_ktest_mask64_u8(__m512i __A, __m512i __B, __m512i __C, __m512
                           _mm512_cmpneq_epu8_mask(__C, __D), CF);
 }
 
+// Test constexpr handling.
+#if defined(__cplusplus) && (__cplusplus >= 201402L)
+constexpr unsigned char
+test_ktest_mask64_u8(unsigned long long A, unsigned long long B) {
+  unsigned char and_not{};
+  return (_ktest_mask64_u8(A, B, &and_not) << 4) | and_not;
+}
+
+void _ktest_mask64_u8() {
+  constexpr unsigned long long A1 = 0x0000'0000'0000'0000;
+  constexpr unsigned long long B1 = 0x0000'0000'0000'0000;
+  constexpr unsigned char expected_result_1 = 0x11;
+  static_assert(test_ktest_mask64_u8(A1, B1) == expected_result_1);
+  constexpr unsigned long long A2 = 0x0000'0000'0000'0000;
+  constexpr unsigned long long B2 = 0x8000'0000'0000'0000;
+  constexpr unsigned char expected_result_2 = 0x10;
+  static_assert(test_ktest_mask64_u8(A2, B2) == expected_result_2);
+  constexpr unsigned long long A3 = 0xF000'0000'0000'0000;
+  constexpr unsigned long long B3 = 0x8000'0000'0000'0000;
+  constexpr unsigned char expected_result_3 = 0x01;
+  static_assert(test_ktest_mask64_u8(A3, B3) == expected_result_3);
+  constexpr unsigned long long A4 = 0x0123'4567'89AB'CDEF;
+  constexpr unsigned long long B4 = 0x0123'4567'89AB'CDEF;
+  constexpr unsigned char expected_result_4 = 0x01;
+  static_assert(test_ktest_mask64_u8(A4, B4) == expected_result_4);
+}
+#endif
+
 __mmask32 test_kadd_mask32(__m512i __A, __m512i __B, __m512i __C, __m512i __D, __m512i __E, __m512i __F) {
   // CHECK-LABEL: test_kadd_mask32
   // CHECK: [[LHS:%.*]] = bitcast i32 %{{.*}} to <32 x i1>
diff --git a/clang/test/CodeGen/X86/avx512dq-builtins.c b/clang/test/CodeGen/X86/avx512dq-builtins.c
index 9c4ada3a2b7b8..efe983ce5b10c 100644
--- a/clang/test/CodeGen/X86/avx512dq-builtins.c
+++ b/clang/test/CodeGen/X86/avx512dq-builtins.c
@@ -117,6 +117,10 @@ unsigned char test_kortestz_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m5
                             _mm512_cmpneq_epu64_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_kortestz_mask8_u8(0x00, 0x00) == 1);
+TEST_CONSTEXPR(_kortestz_mask8_u8(0x00, 0x80) == 0);
+TEST_CONSTEXPR(_kortestz_mask8_u8(0x01, 0xFE) == 0);
+
 unsigned char test_kortestc_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_kortestc_mask8_u8
   // CHECK: [[LHS:%.*]] = bitcast i8 %{{.*}} to <8 x i1>
@@ -130,6 +134,10 @@ unsigned char test_kortestc_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m5
                             _mm512_cmpneq_epu64_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_kortestc_mask8_u8(0x00, 0x00) == 0);
+TEST_CONSTEXPR(_kortestc_mask8_u8(0x00, 0x80) == 0);
+TEST_CONSTEXPR(_kortestc_mask8_u8(0x01, 0xFE) == 1);
+
 unsigned char test_kortest_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D, unsigned char *CF) {
   // CHECK-LABEL: test_kortest_mask8_u8
   // CHECK: [[LHS:%.*]] = bitcast i8 %{{.*}} to <8 x i1>
@@ -150,6 +158,30 @@ unsigned char test_kortest_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m51
                            _mm512_cmpneq_epu64_mask(__C, __D), CF);
 }
 
+// Test constexpr handling.
+#if defined(__cplusplus) && (__cplusplus >= 201103L)
+constexpr unsigned char
+test_kortest_mask8_u8(unsigned char A, unsigned char B) {
+  unsigned char all_ones{};
+  return (_kortest_mask8_u8(A, B, &all_ones) << 4) | all_ones;
+}
+
+void _kortest_mask8_u8() {
+  constexpr unsigned char A1 = 0x00;
+  constexpr unsigned char B1 = 0x00;
+  constexpr unsigned char expected_result_1 = 0x10;
+  static_assert(test_kortest_mask8_u8(A1, B1) == expected_result_1);
+  constexpr unsigned char A2 = 0x00;
+  constexpr unsigned char B2 = 0x80;
+  constexpr unsigned char expected_result_2 = 0x00;
+  static_assert(test_kortest_mask8_u8(A2, B2) == expected_result_2);
+  constexpr unsigned char A3 = 0x01;
+  constexpr unsigned char B3 = 0xFE;
+  constexpr unsigned char expected_result_3 = 0x01;
+  static_assert(test_kortest_mask8_u8(A3, B3) == expected_result_3);
+}
+#endif
+
 unsigned char test_ktestz_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_ktestz_mask8_u8
   // CHECK: [[LHS:%.*]] = bitcast i8 %{{.*}} to <8 x i1>
@@ -160,6 +192,11 @@ unsigned char test_ktestz_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m512
                           _mm512_cmpneq_epu64_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_ktestz_mask8_u8(0x00, 0x00) == 1);
+TEST_CONSTEXPR(_ktestz_mask8_u8(0x00, 0x80) == 1);
+TEST_CONSTEXPR(_ktestz_mask8_u8(0xF0, 0x80) == 0);
+TEST_CONSTEXPR(_ktestz_mask8_u8(0x01, 0x01) == 0);
+
 unsigned char test_ktestc_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_ktestc_mask8_u8
   // CHECK: [[LHS:%.*]] = bitcast i8 %{{.*}} to <8 x i1>
@@ -170,6 +207,11 @@ unsigned char test_ktestc_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m512
                           _mm512_cmpneq_epu64_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_ktestc_mask8_u8(0x00, 0x00) == 1);
+TEST_CONSTEXPR(_ktestc_mask8_u8(0x00, 0x80) == 0);
+TEST_CONSTEXPR(_ktestc_mask8_u8(0xF0, 0x80) == 1);
+TEST_CONSTEXPR(_ktestc_mask8_u8(0x01, 0x01) == 1);
+
 unsigned char test_ktest_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D, unsigned char *CF) {
   // CHECK-LABEL: test_ktest_mask8_u8
   // CHECK: [[LHS:%.*]] = bitcast i8 %{{.*}} to <8 x i1>
@@ -184,6 +226,34 @@ unsigned char test_ktest_mask8_u8(__m512i __A, __m512i __B, __m512i __C, __m512i
                          _mm512_cmpneq_epu64_mask(__C, __D), CF);
 }
 
+// Test constexpr handling.
+#if defined(__cplusplus) && (__cplusplus >= 201103L)
+constexpr unsigned char
+test_ktest_mask8_u8(unsigned char A, unsigned char B) {
+  unsigned char all_ones{};
+  return (_ktest_mask8_u8(A, B, &all_ones) << 4) | all_ones;
+}
+
+void _ktest_mask8_u8() {
+  constexpr unsigned char A1 = 0x00;
+  constexpr unsigned char B1 = 0x00;
+  constexpr unsigned char expected_result_1 = 0x11;
+  static_assert(test_ktest_mask8_u8(A1, B1) == expected_result_1);
+  constexpr unsigned char A2 = 0x00;
+  constexpr unsigned char B2 = 0x80;
+  constexpr unsigned char expected_result_2 = 0x10;
+  static_assert(test_ktest_mask8_u8(A2, B2) == expected_result_2);
+  constexpr unsigned char A3 = 0xF0;
+  constexpr unsigned char B3 = 0x80;
+  constexpr unsigned char expected_result_3 = 0x01;
+  static_assert(test_ktest_mask8_u8(A3, B3) == expected_result_3);
+  constexpr unsigned char A4 = 0x01;
+  constexpr unsigned char B4 = 0x01;
+  constexpr unsigned char expected_result_4 = 0x01;
+  static_assert(test_ktest_mask8_u8(A4, B4) == expected_result_4);
+}
+#endif
+
 unsigned char test_ktestz_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_ktestz_mask16_u8
   // CHECK: [[LHS:%.*]] = bitcast i16 %{{.*}} to <16 x i1>
@@ -194,6 +264,11 @@ unsigned char test_ktestz_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m51
                            _mm512_cmpneq_epu32_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_ktestz_mask16_u8(0x0000, 0x0000) == 1);
+TEST_CONSTEXPR(_ktestz_mask16_u8(0x0000, 0x8000) == 1);
+TEST_CONSTEXPR(_ktestz_mask16_u8(0xF000, 0x8000) == 0);
+TEST_CONSTEXPR(_ktestz_mask16_u8(0x0123, 0x0123) == 0);
+
 unsigned char test_ktestc_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_ktestc_mask16_u8
   // CHECK: [[LHS:%.*]] = bitcast i16 %{{.*}} to <16 x i1>
@@ -204,6 +279,11 @@ unsigned char test_ktestc_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m51
                            _mm512_cmpneq_epu32_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_ktestc_mask16_u8(0x0000, 0x0000) == 1);
+TEST_CONSTEXPR(_ktestc_mask16_u8(0x0000, 0x8000) == 0);
+TEST_CONSTEXPR(_ktestc_mask16_u8(0xF000, 0x8000) == 1);
+TEST_CONSTEXPR(_ktestc_mask16_u8(0x0123, 0x0123) == 1);
+
 unsigned char test_ktest_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D, unsigned char *CF) {
   // CHECK-LABEL: test_ktest_mask16_u8
   // CHECK: [[LHS:%.*]] = bitcast i16 %{{.*}} to <16 x i1>
@@ -218,6 +298,34 @@ unsigned char test_ktest_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m512
                           _mm512_cmpneq_epu32_mask(__C, __D), CF);
 }
 
+// Test constexpr handling.
+#if defined(__cplusplus) && (__cplusplus >= 201103L)
+constexpr unsigned char
+test_ktest_mask16_u8(unsigned int A, unsigned int B) {
+  unsigned char all_ones{};
+  return (_ktest_mask16_u8(A, B, &all_ones) << 4) | all_ones;
+}
+
+void _ktest_mask16_u8() {
+  constexpr unsigned int A1 = 0x0000;
+  constexpr unsigned int B1 = 0x0000;
+  constexpr unsigned char expected_result_1 = 0x11;
+  static_assert(test_ktest_mask16_u8(A1, B1) == expected_result_1);
+  constexpr unsigned int A2 = 0x0000;
+  constexpr unsigned int B2 = 0x8000;
+  constexpr unsigned char expected_result_2 = 0x10;
+  static_assert(test_ktest_mask16_u8(A2, B2) == expected_result_2);
+  constexpr unsigned int A3 = 0xF000;
+  constexpr unsigned int B3 = 0x8000;
+  constexpr unsigned char expected_result_3 = 0x01;
+  static_assert(test_ktest_mask16_u8(A3, B3) == expected_result_3);
+  constexpr unsigned int A4 = 0x0123;
+  constexpr unsigned int B4 = 0x0123;
+  constexpr unsigned char expected_result_4 = 0x01;
+  static_assert(test_ktest_mask16_u8(A4, B4) == expected_result_4);
+}
+#endif
+
 __mmask8 test_kadd_mask8(__m512i __A, __m512i __B, __m512i __C, __m512i __D, __m512i __E, __m512i __F) {
   // CHECK-LABEL: test_kadd_mask8
   // CHECK: [[LHS:%.*]] = bitcast i8 %{{.*}} to <8 x i1>
diff --git a/clang/test/CodeGen/X86/avx512f-builtins.c b/clang/test/CodeGen/X86/avx512f-builtins.c
index 69599379b6b3d..be55d5b42dc02 100644
--- a/clang/test/CodeGen/X86/avx512f-builtins.c
+++ b/clang/test/CodeGen/X86/avx512f-builtins.c
@@ -8965,6 +8965,10 @@ int test_mm512_kortestc(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
                          _mm512_cmpneq_epu32_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_mm512_kortestc(0x0000, 0x0000) == 0);
+TEST_CONSTEXPR(_mm512_kortestc(0x0000, 0x8000) == 0);
+TEST_CONSTEXPR(_mm512_kortestc(0x0123, 0xFEDC) == 1);
+
 int test_mm512_kortestz(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_mm512_kortestz
   // CHECK: [[LHS:%.*]] = bitcast i16 %{{.*}} to <16 x i1>
@@ -8977,6 +8981,10 @@ int test_mm512_kortestz(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
                          _mm512_cmpneq_epu32_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_mm512_kortestz(0x0000, 0x0000) == 1);
+TEST_CONSTEXPR(_mm512_kortestz(0x0000, 0x8000) == 0);
+TEST_CONSTEXPR(_mm512_kortestz(0x0123, 0xFEDC) == 0);
+
 unsigned char test_kortestz_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_kortestz_mask16_u8
   // CHECK: [[LHS:%.*]] = bitcast i16 %{{.*}} to <16 x i1>
@@ -8990,6 +8998,10 @@ unsigned char test_kortestz_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m
                              _mm512_cmpneq_epu32_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_kortestz_mask16_u8(0x0000, 0x0000) == 1);
+TEST_CONSTEXPR(_kortestz_mask16_u8(0x0000, 0x8000) == 0);
+TEST_CONSTEXPR(_kortestz_mask16_u8(0x0123, 0xFEDC) == 0);
+
 unsigned char test_kortestc_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D) {
   // CHECK-LABEL: test_kortestc_mask16_u8
   // CHECK: [[LHS:%.*]] = bitcast i16 %{{.*}} to <16 x i1>
@@ -9003,6 +9015,10 @@ unsigned char test_kortestc_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m
                              _mm512_cmpneq_epu32_mask(__C, __D));
 }
 
+TEST_CONSTEXPR(_kortestc_mask16_u8(0x0000, 0x0000) == 0);
+TEST_CONSTEXPR(_kortestc_mask16_u8(0x0000, 0x8000) == 0);
+TEST_CONSTEXPR(_kortestc_mask16_u8(0x0123, 0xFEDC) == 1);
+
 unsigned char test_kortest_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m512i __D, unsigned char *CF) {
   // CHECK-LABEL: test_kortest_mask16_u8
   // CHECK: [[LHS:%.*]] = bitcast i16 %{{.*}} to <16 x i1>
@@ -9023,6 +9039,30 @@ unsigned char test_kortest_mask16_u8(__m512i __A, __m512i __B, __m512i __C, __m5
                             _mm512_cmpneq_epu32_mask(__C, __D), CF);
 }
 
+// Test constexpr handling.
+#if defined(__cplusplus) && (__cplusplus >= 201103L)
+constexpr unsigned char
+test_kortest_mask16_u8(unsigned short A, unsigned short B) {
+  unsigned char all_ones{};
+  return (_kortest_mask16_u8(A, B, &all_ones) << 4) | all_ones;
+}
+
+void _kortest_mask16_u8() {
+  constexpr unsigned short A1 = 0x0000;
+  constexpr unsigned short B1 = 0x0000;
+  constexpr unsigned char expected_result_1 = 0x10;
+  static_assert(test_kortest_mask16_u8(A1, B1) == expected_result_1);
+  constexpr unsigned short A2 = 0x0000;
+  constexpr unsigned short B2 = 0x8000;
+  constexpr unsigned char expected_result_2 = 0x00;
+  static_assert(test_kortest_mask16_u8(A2, B2) == expected_result_2);
+  constexpr unsigned short A3 = 0x0123;
+  constexpr unsigned short B3 = 0xFEDC;
+  constexpr unsigned char expected_result_3 = 0x01;
+  static_assert(test_kortest_mask16_u8(A3, B3) == expected_result_3);
+}
+#endif
+
 __mmask16 test_mm512_kunpackb(__m512i __A, __m512i __B, __m512i __C, __m512i __D, __m512i __E, __m512i __F) {
   // CHECK-LABEL: test_mm512_kunpackb
   // CHECK: [[LHS:%.*]] = bitcast i16 %{{.*}} to <16 x i1>