diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -5064,6 +5064,7 @@
   //
   static const CostTblEntry AVX2InterleavedLoadTbl[] = {
       {2, MVT::v2i8, 2},  // (load 4i8 and) deinterleave into 2 x 2i8
+      {2, MVT::v4i8, 2},  // (load 8i8 and) deinterleave into 2 x 4i8
 
       {2, MVT::v2i16, 2}, // (load 4i16 and) deinterleave into 2 x 2i16
       {2, MVT::v4i16, 2}, // (load 8i16 and) deinterleave into 2 x 4i16
@@ -5103,6 +5104,7 @@
 
   static const CostTblEntry AVX2InterleavedStoreTbl[] = {
       {2, MVT::v2i8, 1}, // interleave 2 x 2i8 into 4i8 (and store)
+      {2, MVT::v4i8, 1}, // interleave 2 x 4i8 into 8i8 (and store)
 
       {2, MVT::v2i16, 1}, // interleave 2 x 2i16 into 4i16 (and store)
       {2, MVT::v4i16, 1}, // interleave 2 x 4i16 into 8i16 (and store)
diff --git a/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-2.ll b/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-2.ll
--- a/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-2.ll
+++ b/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-2.ll
@@ -27,7 +27,7 @@
 ;
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 3 for VF 2 For instruction:   %v0 = load i8, i8* %in0, align 1
-; AVX2: LV: Found an estimated cost of 17 for VF 4 For instruction:   %v0 = load i8, i8* %in0, align 1
+; AVX2: LV: Found an estimated cost of 3 for VF 4 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 33 for VF 8 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 81 for VF 16 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 166 for VF 32 For instruction:   %v0 = load i8, i8* %in0, align 1
diff --git a/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-2.ll b/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-2.ll
--- a/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-2.ll
+++ b/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-2.ll
@@ -27,7 +27,7 @@
 
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 2 for VF 2 For instruction:   store i8 %v1, i8* %out1, align 1
-; AVX2: LV: Found an estimated cost of 17 for VF 4 For instruction:   store i8 %v1, i8* %out1, align 1
+; AVX2: LV: Found an estimated cost of 2 for VF 4 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 33 for VF 8 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 67 for VF 16 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 166 for VF 32 For instruction:   store i8 %v1, i8* %out1, align 1