diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index e40acf305ebfe1..9b2be2af79561a 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -1778,7 +1778,8 @@ int X86TTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
     { ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i16, 4 },
     { ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i16, 4 },
 
-    { ISD::TRUNCATE,    MVT::v4i8,   MVT::v4i16,  2 },
+    { ISD::TRUNCATE,    MVT::v2i8,   MVT::v2i16,  1 },
+    { ISD::TRUNCATE,    MVT::v4i8,   MVT::v4i16,  1 },
     { ISD::TRUNCATE,    MVT::v8i8,   MVT::v8i16,  1 },
     { ISD::TRUNCATE,    MVT::v4i8,   MVT::v4i32,  1 },
     { ISD::TRUNCATE,    MVT::v4i16,  MVT::v4i32,  1 },
@@ -1868,10 +1869,10 @@ int X86TTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
     { ISD::SIGN_EXTEND, MVT::v4i64,  MVT::v4i32,  5 },
 
     { ISD::TRUNCATE,    MVT::v2i8,   MVT::v2i16,  2 }, // PAND+PACKUSWB
-    { ISD::TRUNCATE,    MVT::v4i8,   MVT::v4i16,  4 },
-    { ISD::TRUNCATE,    MVT::v8i8,   MVT::v8i16,  2 },
+    { ISD::TRUNCATE,    MVT::v4i8,   MVT::v4i16,  2 }, // PAND+PACKUSWB
+    { ISD::TRUNCATE,    MVT::v8i8,   MVT::v8i16,  2 }, // PAND+PACKUSWB
     { ISD::TRUNCATE,    MVT::v16i8,  MVT::v16i16, 3 },
-    { ISD::TRUNCATE,    MVT::v2i8,   MVT::v2i32,  3 }, // PAND+3*PACKUSWB
+    { ISD::TRUNCATE,    MVT::v2i8,   MVT::v2i32,  3 }, // PAND+2*PACKUSWB
     { ISD::TRUNCATE,    MVT::v2i16,  MVT::v2i32,  1 },
     { ISD::TRUNCATE,    MVT::v4i8,   MVT::v4i32,  3 },
     { ISD::TRUNCATE,    MVT::v4i16,  MVT::v4i32,  3 },
diff --git a/llvm/test/Analysis/CostModel/X86/sse-itoi.ll b/llvm/test/Analysis/CostModel/X86/sse-itoi.ll
index 3d18ad8a06b10b..a17b75769879b0 100644
--- a/llvm/test/Analysis/CostModel/X86/sse-itoi.ll
+++ b/llvm/test/Analysis/CostModel/X86/sse-itoi.ll
@@ -584,13 +584,13 @@ define void @truncate_v8i16_to_v8i8(<8 x i16>* %a) {
 define void @truncate_v4i16_to_v4i8(<4 x i16>* %a) {
 ; SSE2-LABEL: 'truncate_v4i16_to_v4i8'
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = load <4 x i16>, <4 x i16>* %a
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %2 = trunc <4 x i16> %1 to <4 x i8>
+; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %2 = trunc <4 x i16> %1 to <4 x i8>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: store <4 x i8> %2, <4 x i8>* undef, align 4
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
 ; SSE41-LABEL: 'truncate_v4i16_to_v4i8'
 ; SSE41-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = load <4 x i16>, <4 x i16>* %a
-; SSE41-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %2 = trunc <4 x i16> %1 to <4 x i8>
+; SSE41-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %2 = trunc <4 x i16> %1 to <4 x i8>
 ; SSE41-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: store <4 x i8> %2, <4 x i8>* undef, align 4
 ; SSE41-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
diff --git a/llvm/test/Analysis/CostModel/X86/trunc.ll b/llvm/test/Analysis/CostModel/X86/trunc.ll
index 515bd701e18ae0..85ed9d06f19f25 100644
--- a/llvm/test/Analysis/CostModel/X86/trunc.ll
+++ b/llvm/test/Analysis/CostModel/X86/trunc.ll
@@ -175,7 +175,7 @@ define i32 @trunc_vXi8() {
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i8>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 31 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i8>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
-; SSE2-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
+; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i16 = trunc <8 x i16> undef to <8 x i8>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V16i16 = trunc <16 x i16> undef to <16 x i8>
 ; SSE2-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %V32i16 = trunc <32 x i16> undef to <32 x i8>
@@ -196,7 +196,7 @@ define i32 @trunc_vXi8() {
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i8>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 31 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i8>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
-; SSSE3-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
+; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i16 = trunc <8 x i16> undef to <8 x i8>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V16i16 = trunc <16 x i16> undef to <16 x i8>
 ; SSSE3-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %V32i16 = trunc <32 x i16> undef to <32 x i8>
@@ -216,8 +216,8 @@ define i32 @trunc_vXi8() {
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %V16i32 = trunc <16 x i32> undef to <16 x i8>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i8>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 31 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i8>
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
-; SSE42-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
+; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
+; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i16 = trunc <8 x i16> undef to <8 x i8>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V16i16 = trunc <16 x i16> undef to <16 x i8>
 ; SSE42-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %V32i16 = trunc <32 x i16> undef to <32 x i8>
@@ -237,8 +237,8 @@ define i32 @trunc_vXi8() {
 ; AVX1-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %V16i32 = trunc <16 x i32> undef to <16 x i8>
 ; AVX1-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i8>
 ; AVX1-NEXT:  Cost Model: Found an estimated cost of 31 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i8>
-; AVX1-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
-; AVX1-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
+; AVX1-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
+; AVX1-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
 ; AVX1-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i16 = trunc <8 x i16> undef to <8 x i8>
 ; AVX1-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V16i16 = trunc <16 x i16> undef to <16 x i8>
 ; AVX1-NEXT:  Cost Model: Found an estimated cost of 9 for instruction: %V32i16 = trunc <32 x i16> undef to <32 x i8>
@@ -258,8 +258,8 @@ define i32 @trunc_vXi8() {
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %V16i32 = trunc <16 x i32> undef to <16 x i8>
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i8>
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 31 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i8>
-; AVX2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
-; AVX2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
+; AVX2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
+; AVX2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i16 = trunc <8 x i16> undef to <8 x i8>
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V16i16 = trunc <16 x i16> undef to <16 x i8>
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 9 for instruction: %V32i16 = trunc <32 x i16> undef to <32 x i8>
@@ -279,8 +279,8 @@ define i32 @trunc_vXi8() {
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16i32 = trunc <16 x i32> undef to <16 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i8>
-; AVX512F-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
-; AVX512F-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i16 = trunc <8 x i16> undef to <8 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V16i16 = trunc <16 x i16> undef to <16 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V32i16 = trunc <32 x i16> undef to <32 x i8>
@@ -300,8 +300,8 @@ define i32 @trunc_vXi8() {
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16i32 = trunc <16 x i32> undef to <16 x i8>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i8>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i8>
-; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
-; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i16 = trunc <8 x i16> undef to <8 x i8>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16i16 = trunc <16 x i16> undef to <16 x i8>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V32i16 = trunc <32 x i16> undef to <32 x i8>
@@ -321,8 +321,8 @@ define i32 @trunc_vXi8() {
 ; BTVER2-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %V16i32 = trunc <16 x i32> undef to <16 x i8>
 ; BTVER2-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i8>
 ; BTVER2-NEXT:  Cost Model: Found an estimated cost of 31 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i8>
-; BTVER2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
-; BTVER2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
+; BTVER2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i8>
+; BTVER2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i8>
 ; BTVER2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i16 = trunc <8 x i16> undef to <8 x i8>
 ; BTVER2-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V16i16 = trunc <16 x i16> undef to <16 x i8>
 ; BTVER2-NEXT:  Cost Model: Found an estimated cost of 9 for instruction: %V32i16 = trunc <32 x i16> undef to <32 x i8>