diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
@@ -738,7 +738,7 @@
       return getShuffleCost(TTI::SK_ExtractSubvector, SrcTy, SubIndex, Ty);
 
     if (Shuffle->changesLength())
-      return -1;
+      BaseT::getUserCost(U, Operands);
 
     if (Shuffle->isIdentity())
       return 0;
diff --git a/llvm/test/Analysis/CostModel/AMDGPU/shufflevector.ll b/llvm/test/Analysis/CostModel/AMDGPU/shufflevector.ll
--- a/llvm/test/Analysis/CostModel/AMDGPU/shufflevector.ll
+++ b/llvm/test/Analysis/CostModel/AMDGPU/shufflevector.ll
@@ -1,7 +1,7 @@
-; RUN: opt -cost-model -analyze -mtriple=amdgcn-unknown-amdhsa -mcpu=gfx900 %s | FileCheck -check-prefixes=GFX9,GCN %s
-; RUN: opt -cost-model -analyze -mtriple=amdgcn-unknown-amdhsa -mcpu=fiji %s | FileCheck -check-prefixes=VI,GCN %s
-; RUN: opt -cost-model -cost-kind=code-size -analyze -mtriple=amdgcn-unknown-amdhsa -mcpu=gfx900 %s | FileCheck -check-prefixes=GFX9,GCN %s
-; RUN: opt -cost-model -cost-kind=code-size -analyze -mtriple=amdgcn-unknown-amdhsa -mcpu=fiji %s | FileCheck -check-prefixes=VI,GCN %s
+; RUN: opt -cost-model -analyze -mtriple=amdgcn-unknown-amdhsa -mcpu=gfx900 %s | FileCheck -check-prefixes=GFX9,GCN,TPT %s
+; RUN: opt -cost-model -analyze -mtriple=amdgcn-unknown-amdhsa -mcpu=fiji %s | FileCheck -check-prefixes=VI,GCN,TPT %s
+; RUN: opt -cost-model -cost-kind=code-size -analyze -mtriple=amdgcn-unknown-amdhsa -mcpu=gfx900 %s | FileCheck -check-prefixes=GFX9,GCN,CS %s
+; RUN: opt -cost-model -cost-kind=code-size -analyze -mtriple=amdgcn-unknown-amdhsa -mcpu=fiji %s | FileCheck -check-prefixes=VI,GCN,CS %s
 
 ; GCN-LABEL: 'shufflevector_00_v2i16'
 ; GFX9: estimated cost of 0 for {{.*}} shufflevector <2 x i16> %vec, <2 x i16> undef, <2 x i32> zeroinitializer
@@ -51,3 +51,14 @@
   store <2 x i16> %shuf, <2 x i16> addrspace(1)* %out
   ret void
 }
+
+; GCN-LABEL: 'shufflevector_xxx'
+; TPT: Unknown cost for {{.*}} shufflevector <2 x i8> %vec, <2 x i8> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
+; CS: estimated cost of 8 for {{.*}} shufflevector <2 x i8> %vec, <2 x i8> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
+; Should not assert
+define amdgpu_kernel void @shufflevector_xxx(<4 x i8> addrspace(1)* %out, <2 x i8> addrspace(1)* %vaddr) {
+  %vec = load <2 x i8>, <2 x i8> addrspace(1)* %vaddr
+  %shuf = shufflevector <2 x i8> %vec, <2 x i8> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
+  store <4 x i8> %shuf, <4 x i8> addrspace(1)* %out
+  ret void
+}