Index: include/llvm/Support/Endian.h
===================================================================
--- include/llvm/Support/Endian.h
+++ include/llvm/Support/Endian.h
@@ -15,6 +15,7 @@
 #define LLVM_SUPPORT_ENDIAN_H
 
 #include "llvm/Support/AlignOf.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/SwapByteOrder.h"
 
@@ -56,6 +57,26 @@
   return byte_swap<value_type, endian>(ret);
 }
 
+/// Read a value of a particular endianness and size from memory.
+template<typename value_type,
+         endianness endian,
+         std::size_t alignment>
+inline value_type read(const void *memory, std::size_t size) {
+  switch (size) {
+  default:
+    llvm_unreachable("Unexpected size");
+    break;
+  case 1:
+    return support::endian::read<int8_t, endian, alignment>(memory);
+  case 2:
+    return support::endian::read<int16_t, endian, alignment>(memory);
+  case 4:
+    return support::endian::read<int32_t, endian, alignment>(memory);
+  case 8:
+    return support::endian::read<int64_t, endian, alignment>(memory);
+  }
+}
+
 /// Read a value of a particular endianness from a buffer, and increment the
 /// buffer past that value.
 template<typename value_type, endianness endian, std::size_t alignment>
Index: lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOI386.h
===================================================================
--- lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOI386.h
+++ lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOI386.h
@@ -142,8 +142,9 @@
     RelI->getOffset(Offset);
     uint8_t *LocalAddress = Section.Address + Offset;
     unsigned NumBytes = 1 << Size;
-    int64_t Addend = 0;
-    memcpy(&Addend, LocalAddress, NumBytes);
+    int64_t Addend =
+        support::endian::read<int64_t, support::little, support::unaligned>(
+            LocalAddress, NumBytes);
 
     ++RelI;
     MachO::any_relocation_info RE2 =
@@ -202,8 +203,9 @@
     RelI->getOffset(Offset);
     uint8_t *LocalAddress = Section.Address + Offset;
     unsigned NumBytes = 1 << Size;
-    int64_t Addend = 0;
-    memcpy(&Addend, LocalAddress, NumBytes);
+    int64_t Addend =
+        support::endian::read<int64_t, support::little, support::unaligned>(
+            LocalAddress, NumBytes);
 
     unsigned SymbolBaseAddr = MachO->getScatteredRelocationValue(RE);
     section_iterator TargetSI = getSectionByAddress(*MachO, SymbolBaseAddr);