diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 8a48b4eae77e..49dfc60d0ca8 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -8846,7 +8846,8 @@ Value *CodeGenFunction::EmitX86BuiltinExpr(unsigned BuiltinID,
     RHS = Builder.CreateShuffleVector(RHS, RHS,
                                       makeArrayRef(Indices, NumElts / 2));
     // Concat the vectors.
-    Value *Res = Builder.CreateShuffleVector(LHS, RHS,
+    // NOTE: Operands are swapped to match the intrinsic definition.
+    Value *Res = Builder.CreateShuffleVector(RHS, LHS,
                                              makeArrayRef(Indices, NumElts));
     return Builder.CreateBitCast(Res, Ops[0]->getType());
   }
diff --git a/clang/test/CodeGen/avx512bw-builtins.c b/clang/test/CodeGen/avx512bw-builtins.c
index bfdf46d261fa..4288c086924b 100644
--- a/clang/test/CodeGen/avx512bw-builtins.c
+++ b/clang/test/CodeGen/avx512bw-builtins.c
@@ -1632,7 +1632,7 @@ __mmask64 test_mm512_kunpackd(__m512i __A, __m512i __B, __m512i __C, __m512i __D
   // CHECK: [[RHS:%.*]] = bitcast i64 %{{.*}} to <64 x i1>
   // CHECK: [[LHS2:%.*]] = shufflevector <64 x i1> [[LHS]], <64 x i1> [[LHS]], <32 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31>
   // CHECK: [[RHS2:%.*]] = shufflevector <64 x i1> [[RHS]], <64 x i1> [[RHS]], <32 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31>
-  // CHECK: [[CONCAT:%.*]] = shufflevector <32 x i1> [[LHS2]], <32 x i1> [[RHS2]], <64 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31, i32 32, i32 33, i32 34, i32 35, i32 36, i32 37, i32 38, i32 39, i32 40, i32 41, i32 42, i32 43, i32 44, i32 45, i32 46, i32 47, i32 48, i32 49, i32 50, i32 51, i32 52, i32 53, i32 54, i32 55, i32 56, i32 57, i32 58, i32 59, i32 60, i32 61, i32 62, i32 63>
+  // CHECK: [[CONCAT:%.*]] = shufflevector <32 x i1> [[RHS2]], <32 x i1> [[LHS2]], <64 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31, i32 32, i32 33, i32 34, i32 35, i32 36, i32 37, i32 38, i32 39, i32 40, i32 41, i32 42, i32 43, i32 44, i32 45, i32 46, i32 47, i32 48, i32 49, i32 50, i32 51, i32 52, i32 53, i32 54, i32 55, i32 56, i32 57, i32 58, i32 59, i32 60, i32 61, i32 62, i32 63>
   // CHECK: bitcast <64 x i1> [[CONCAT]] to i64
   return _mm512_mask_cmpneq_epu8_mask(_mm512_kunpackd(_mm512_cmpneq_epu8_mask(__B, __A),_mm512_cmpneq_epu8_mask(__C, __D)), __E, __F); 
 }
@@ -1643,7 +1643,7 @@ __mmask32 test_mm512_kunpackw(__m512i __A, __m512i __B, __m512i __C, __m512i __D
   // CHECK: [[RHS:%.*]] = bitcast i32 %{{.*}} to <32 x i1>
   // CHECK: [[LHS2:%.*]] = shufflevector <32 x i1> [[LHS]], <32 x i1> [[LHS]], <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
   // CHECK: [[RHS2:%.*]] = shufflevector <32 x i1> [[RHS]], <32 x i1> [[RHS]], <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-  // CHECK: [[CONCAT:%.*]] = shufflevector <16 x i1> [[LHS2]], <16 x i1> [[RHS2]], <32 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31>
+  // CHECK: [[CONCAT:%.*]] = shufflevector <16 x i1> [[RHS2]], <16 x i1> [[LHS2]], <32 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31>
   return _mm512_mask_cmpneq_epu16_mask(_mm512_kunpackw(_mm512_cmpneq_epu16_mask(__B, __A),_mm512_cmpneq_epu16_mask(__C, __D)), __E, __F); 
 }
 
diff --git a/clang/test/CodeGen/avx512f-builtins.c b/clang/test/CodeGen/avx512f-builtins.c
index 8e6ed959aedf..5847f311ef5b 100644
--- a/clang/test/CodeGen/avx512f-builtins.c
+++ b/clang/test/CodeGen/avx512f-builtins.c
@@ -6281,7 +6281,7 @@ __mmask16 test_mm512_kunpackb(__m512i __A, __m512i __B, __m512i __C, __m512i __D
   // CHECK: [[RHS:%.*]] = bitcast i16 %{{.*}} to <16 x i1>
   // CHECK: [[LHS2:%.*]] = shufflevector <16 x i1> [[LHS]], <16 x i1> [[LHS]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
   // CHECK: [[RHS2:%.*]] = shufflevector <16 x i1> [[RHS]], <16 x i1> [[RHS]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-  // CHECK: [[CONCAT:%.*]] = shufflevector <8 x i1> [[LHS2]], <8 x i1> [[RHS2]], <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
+  // CHECK: [[CONCAT:%.*]] = shufflevector <8 x i1> [[RHS2]], <8 x i1> [[LHS2]], <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
   // CHECK: bitcast <16 x i1> [[CONCAT]] to i16
   return _mm512_mask_cmpneq_epu32_mask(_mm512_kunpackb(_mm512_cmpneq_epu32_mask(__A, __B),
                                                        _mm512_cmpneq_epu32_mask(__C, __D)),