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
@@ -1620,6 +1620,7 @@
     { ISD::TRUNCATE,    MVT::v4i1,   MVT::v4i16,  2 }, // widen to zmm
     { ISD::TRUNCATE,    MVT::v4i8,   MVT::v4i16,  2 }, // vpmovwb
     { ISD::TRUNCATE,    MVT::v8i1,   MVT::v8i8,   2 }, // widen to zmm
+    { ISD::TRUNCATE,    MVT::v8i1,   MVT::v16i8,  2 }, // widen to zmm
     { ISD::TRUNCATE,    MVT::v8i1,   MVT::v8i16,  2 }, // widen to zmm
     { ISD::TRUNCATE,    MVT::v8i8,   MVT::v8i16,  2 }, // vpmovwb
     { ISD::TRUNCATE,    MVT::v16i1,  MVT::v16i8,  2 }, // widen to zmm
diff --git a/llvm/test/Analysis/CostModel/X86/trunc.ll b/llvm/test/Analysis/CostModel/X86/trunc.ll
--- a/llvm/test/Analysis/CostModel/X86/trunc.ll
+++ b/llvm/test/Analysis/CostModel/X86/trunc.ll
@@ -2490,9 +2490,9 @@
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i8 = trunc <2 x i8> undef to <2 x i1>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %V3i8 = trunc <3 x i8> undef to <3 x i1>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i8 = trunc <4 x i8> undef to <4 x i1>
-; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 10 for instruction: %V5i8 = trunc <5 x i8> undef to <5 x i1>
-; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %V6i8 = trunc <6 x i8> undef to <6 x i1>
-; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 14 for instruction: %V7i8 = trunc <7 x i8> undef to <7 x i1>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V5i8 = trunc <5 x i8> undef to <5 x i1>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V6i8 = trunc <6 x i8> undef to <6 x i1>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V7i8 = trunc <7 x i8> undef to <7 x i1>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i8 = trunc <8 x i8> undef to <8 x i1>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V10i8 = trunc <10 x i8> undef to <10 x i1>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V12i8 = trunc <12 x i8> undef to <12 x i1>