Index: lldb/trunk/source/Core/DumpDataExtractor.cpp
===================================================================
--- lldb/trunk/source/Core/DumpDataExtractor.cpp
+++ lldb/trunk/source/Core/DumpDataExtractor.cpp
@@ -583,8 +583,10 @@
             } else if (item_bit_size == ast->getTypeSize(ast->LongDoubleTy)) {
               const auto &semantics =
                   ast->getFloatTypeSemantics(ast->LongDoubleTy);
-              const auto byte_size =
-                  (llvm::APFloat::getSizeInBits(semantics) + 7) / 8;
+
+              offset_t byte_size = item_byte_size;
+              if (&semantics == &llvm::APFloatBase::x87DoubleExtended())
+                byte_size = (llvm::APFloat::getSizeInBits(semantics) + 7) / 8;
 
               llvm::APInt apint;
               if (GetAPInt(DE, &offset, byte_size, apint)) {