Replace OS::MemCopy with OS::MemMove (just as fast but more flexible).

src/arm/assembler-arm.cc

Index: src/arm/assembler-arm.cc
diff --git a/src/arm/assembler-arm.cc b/src/arm/assembler-arm.cc
index 3741ac2cbc1d28b05600eafa1394ca1f99c0fafc..b0dbe061e2024cc69c24f164478b021ceb720868 100644
--- a/src/arm/assembler-arm.cc
+++ b/src/arm/assembler-arm.cc
@@ -1996,7 +1996,7 @@ void  Assembler::vstm(BlockAddrMode am,
 
 static void DoubleAsTwoUInt32(double d, uint32_t* lo, uint32_t* hi) {
   uint64_t i;
-  memcpy(&i, &d, 8);
+  OS::MemCopy(&i, &d, 8);
 
   *lo = i & 0xffffffff;
   *hi = i >> 32;
@@ -2700,9 +2700,9 @@ void Assembler::GrowBuffer() {
   // Copy the data.
   int pc_delta = desc.buffer - buffer_;
   int rc_delta = (desc.buffer + desc.buffer_size) - (buffer_ + buffer_size_);
-  memmove(desc.buffer, buffer_, desc.instr_size);
-  memmove(reloc_info_writer.pos() + rc_delta,
-          reloc_info_writer.pos(), desc.reloc_size);
+  OS::MemMove(desc.buffer, buffer_, desc.instr_size);
+  OS::MemMove(reloc_info_writer.pos() + rc_delta,
+              reloc_info_writer.pos(), desc.reloc_size);
 
   // Switch buffers.
   DeleteArray(buffer_);
@@ -2951,7 +2951,7 @@ void Assembler::CheckConstPool(bool force_emit, bool require_jump) {
 
       const double double_data = rinfo.data64();
       uint64_t uint_data = 0;
-      memcpy(&uint_data, &double_data, sizeof(double_data));
+      OS::MemCopy(&uint_data, &double_data, sizeof(double_data));
       emit(uint_data & 0xFFFFFFFF);
       emit(uint_data >> 32);
     }