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

src/mips/assembler-mips.cc

Index: src/mips/assembler-mips.cc
diff --git a/src/mips/assembler-mips.cc b/src/mips/assembler-mips.cc
index c255d0fbda970efa8e93df9a66d5cc88a23e9fb4..a3a840defd4e015a2bd19c17614bd3edfcfce11e 100644
--- a/src/mips/assembler-mips.cc
+++ b/src/mips/assembler-mips.cc
@@ -1679,7 +1679,7 @@ void Assembler::cfc1(Register rt, FPUControlRegister fs) {
 
 void Assembler::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;
@@ -1997,9 +1997,9 @@ 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_);