diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -1602,7 +1602,9 @@
 
   static const TypeConversionCostTblEntry
   ConversionTbl[] = {
-    { ISD::TRUNCATE, MVT::v4i16, MVT::v4i32,  1 },
+    { ISD::TRUNCATE, MVT::v4i16, MVT::v4i32,  1 },  // xtn
+    { ISD::TRUNCATE, MVT::v8i8,  MVT::v8i16,  1 },  // xtn
+    { ISD::TRUNCATE, MVT::v2i32, MVT::v2i64,  1 },  // xtn
     { ISD::TRUNCATE, MVT::v4i32, MVT::v4i64,  0 },
     { ISD::TRUNCATE, MVT::v8i8,  MVT::v8i32,  3 },
     { ISD::TRUNCATE, MVT::v16i8, MVT::v16i32, 6 },
diff --git a/llvm/test/Analysis/CostModel/AArch64/cast.ll b/llvm/test/Analysis/CostModel/AArch64/cast.ll
--- a/llvm/test/Analysis/CostModel/AArch64/cast.ll
+++ b/llvm/test/Analysis/CostModel/AArch64/cast.ll
@@ -166,20 +166,20 @@
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %s2i8i64 = trunc <2 x i64> undef to <2 x i8>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s2i16i32 = trunc <2 x i32> undef to <2 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s2i16i64 = trunc <2 x i64> undef to <2 x i16>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s2i32i64 = trunc <2 x i64> undef to <2 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %s2i32i64 = trunc <2 x i64> undef to <2 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s4i8i16 = trunc <4 x i16> undef to <4 x i8>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s4i8i32 = trunc <4 x i32> undef to <4 x i8>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s4i8i64 = trunc <4 x i64> undef to <4 x i8>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %s4i16i32 = trunc <4 x i32> undef to <4 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s4i16i64 = trunc <4 x i64> undef to <4 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s4i32i64 = trunc <4 x i64> undef to <4 x i32>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s8i8i16 = trunc <8 x i16> undef to <8 x i8>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %s8i8i16 = trunc <8 x i16> undef to <8 x i8>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %s8i8i32 = trunc <8 x i32> undef to <8 x i8>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s8i8i64 = trunc <8 x i64> undef to <8 x i8>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %s8i16i32 = trunc <8 x i32> undef to <8 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %s8i16i64 = trunc <8 x i64> undef to <8 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %s8i32i64 = trunc <8 x i64> undef to <8 x i32>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %s16i8i16 = trunc <16 x i16> undef to <16 x i8>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %s16i8i16 = trunc <16 x i16> undef to <16 x i8>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %s16i8i32 = trunc <16 x i32> undef to <16 x i8>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %s16i8i64 = trunc <16 x i64> undef to <16 x i8>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %s16i16i32 = trunc <16 x i32> undef to <16 x i16>