Index: llvm/include/llvm/CodeGen/BasicTTIImpl.h
===================================================================
--- llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -694,8 +694,8 @@
     std::pair<unsigned, MVT> SrcLT = TLI->getTypeLegalizationCost(DL, Src);
     std::pair<unsigned, MVT> DstLT = TLI->getTypeLegalizationCost(DL, Dst);
 
-    unsigned SrcSize = SrcLT.second.getSizeInBits();
-    unsigned DstSize = DstLT.second.getSizeInBits();
+    TypeSize SrcSize = SrcLT.second.getSizeInBits();
+    TypeSize DstSize = DstLT.second.getSizeInBits();
     bool IntOrPtrSrc = Src->isIntegerTy() || Src->isPointerTy();
     bool IntOrPtrDst = Dst->isIntegerTy() || Dst->isPointerTy();
 
@@ -769,8 +769,7 @@
     // Check vector-to-vector casts.
     if (DstVTy && SrcVTy) {
       // If the cast is between same-sized registers, then the check is simple.
-      if (SrcLT.first == DstLT.first &&
-          SrcLT.second.getSizeInBits() == DstLT.second.getSizeInBits()) {
+      if (SrcLT.first == DstLT.first && SrcSize == DstSize) {
 
         // Assume that Zext is done using AND.
         if (Opcode == Instruction::ZExt)
Index: llvm/test/Analysis/CostModel/AArch64/sve-bitcast.ll
===================================================================
--- /dev/null
+++ llvm/test/Analysis/CostModel/AArch64/sve-bitcast.ll
@@ -0,0 +1,11 @@
+; RUN: opt -mtriple=aarch64-linux-gnu -mattr=+sve -cost-model -analyze < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
+
+; CHECK: Found an estimated cost of 0 for instruction:   %b = bitcast <vscale x 2 x double> %a to <vscale x 2 x i64>
+
+define <vscale x 2 x i64> @foo(<vscale x 2 x double> %a, i32 %x) {
+  %b = bitcast <vscale x 2 x double> %a to <vscale x 2 x i64>
+  ret <vscale x 2 x i64> %b
+}