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
@@ -5113,6 +5113,7 @@
 
       {3, MVT::v2i64, 1},  // (load 6i64 and) deinterleave into 3 x 2i64
       {3, MVT::v4i64, 5},  // (load 12i64 and) deinterleave into 3 x 4i64
+      {3, MVT::v8i64, 10},  // (load 24i64 and) deinterleave into 3 x 8i64
 
       {4, MVT::v2i8, 4},  // (load 8i8 and) deinterleave into 4 x 2i8
       {4, MVT::v4i8, 4},   // (load 16i8 and) deinterleave into 4 x 4i8
@@ -5183,6 +5184,7 @@
 
       {3, MVT::v2i64, 4},   // interleave 3 x 2i64 into 6i64 (and store)
       {3, MVT::v4i64, 6},   // interleave 3 x 4i64 into 12i64 (and store)
+      {3, MVT::v8i64, 12},   // interleave 3 x 8i64 into 24i64 (and store)
 
       {4, MVT::v2i8, 4},  // interleave 4 x 2i8 into 8i8 (and store)
       {4, MVT::v4i8, 4},   // interleave 4 x 4i8 into 16i8 (and store)
diff --git a/llvm/test/Analysis/CostModel/X86/interleaved-load-f64-stride-3.ll b/llvm/test/Analysis/CostModel/X86/interleaved-load-f64-stride-3.ll
--- a/llvm/test/Analysis/CostModel/X86/interleaved-load-f64-stride-3.ll
+++ b/llvm/test/Analysis/CostModel/X86/interleaved-load-f64-stride-3.ll
@@ -26,7 +26,7 @@
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   %v0 = load double, double* %in0, align 8
 ; AVX2: LV: Found an estimated cost of 3 for VF 2 For instruction:   %v0 = load double, double* %in0, align 8
 ; AVX2: LV: Found an estimated cost of 8 for VF 4 For instruction:   %v0 = load double, double* %in0, align 8
-; AVX2: LV: Found an estimated cost of 48 for VF 8 For instruction:   %v0 = load double, double* %in0, align 8
+; AVX2: LV: Found an estimated cost of 16 for VF 8 For instruction:   %v0 = load double, double* %in0, align 8
 ; AVX2: LV: Found an estimated cost of 96 for VF 16 For instruction:   %v0 = load double, double* %in0, align 8
 ;
 ; AVX512: LV: Found an estimated cost of 1 for VF 1 For instruction:   %v0 = load double, double* %in0, align 8
diff --git a/llvm/test/Analysis/CostModel/X86/interleaved-load-i64-stride-3.ll b/llvm/test/Analysis/CostModel/X86/interleaved-load-i64-stride-3.ll
--- a/llvm/test/Analysis/CostModel/X86/interleaved-load-i64-stride-3.ll
+++ b/llvm/test/Analysis/CostModel/X86/interleaved-load-i64-stride-3.ll
@@ -26,7 +26,7 @@
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   %v0 = load i64, i64* %in0, align 8
 ; AVX2: LV: Found an estimated cost of 3 for VF 2 For instruction:   %v0 = load i64, i64* %in0, align 8
 ; AVX2: LV: Found an estimated cost of 8 for VF 4 For instruction:   %v0 = load i64, i64* %in0, align 8
-; AVX2: LV: Found an estimated cost of 78 for VF 8 For instruction:   %v0 = load i64, i64* %in0, align 8
+; AVX2: LV: Found an estimated cost of 16 for VF 8 For instruction:   %v0 = load i64, i64* %in0, align 8
 ; AVX2: LV: Found an estimated cost of 156 for VF 16 For instruction:   %v0 = load i64, i64* %in0, align 8
 ;
 ; AVX512: LV: Found an estimated cost of 1 for VF 1 For instruction:   %v0 = load i64, i64* %in0, align 8
diff --git a/llvm/test/Analysis/CostModel/X86/interleaved-store-f64-stride-3.ll b/llvm/test/Analysis/CostModel/X86/interleaved-store-f64-stride-3.ll
--- a/llvm/test/Analysis/CostModel/X86/interleaved-store-f64-stride-3.ll
+++ b/llvm/test/Analysis/CostModel/X86/interleaved-store-f64-stride-3.ll
@@ -26,7 +26,7 @@
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   store double %v2, double* %out2, align 8
 ; AVX2: LV: Found an estimated cost of 6 for VF 2 For instruction:   store double %v2, double* %out2, align 8
 ; AVX2: LV: Found an estimated cost of 9 for VF 4 For instruction:   store double %v2, double* %out2, align 8
-; AVX2: LV: Found an estimated cost of 54 for VF 8 For instruction:   store double %v2, double* %out2, align 8
+; AVX2: LV: Found an estimated cost of 18 for VF 8 For instruction:   store double %v2, double* %out2, align 8
 ; AVX2: LV: Found an estimated cost of 108 for VF 16 For instruction:   store double %v2, double* %out2, align 8
 ;
 ; AVX512: LV: Found an estimated cost of 1 for VF 1 For instruction:   store double %v2, double* %out2, align 8
diff --git a/llvm/test/Analysis/CostModel/X86/interleaved-store-i64-stride-3.ll b/llvm/test/Analysis/CostModel/X86/interleaved-store-i64-stride-3.ll
--- a/llvm/test/Analysis/CostModel/X86/interleaved-store-i64-stride-3.ll
+++ b/llvm/test/Analysis/CostModel/X86/interleaved-store-i64-stride-3.ll
@@ -26,7 +26,7 @@
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   store i64 %v2, i64* %out2, align 8
 ; AVX2: LV: Found an estimated cost of 6 for VF 2 For instruction:   store i64 %v2, i64* %out2, align 8
 ; AVX2: LV: Found an estimated cost of 9 for VF 4 For instruction:   store i64 %v2, i64* %out2, align 8
-; AVX2: LV: Found an estimated cost of 78 for VF 8 For instruction:   store i64 %v2, i64* %out2, align 8
+; AVX2: LV: Found an estimated cost of 18 for VF 8 For instruction:   store i64 %v2, i64* %out2, align 8
 ; AVX2: LV: Found an estimated cost of 156 for VF 16 For instruction:   store i64 %v2, i64* %out2, align 8
 ;
 ; AVX512: LV: Found an estimated cost of 1 for VF 1 For instruction:   store i64 %v2, i64* %out2, align 8