Remove V8_HOST_CAN_READ_UNALIGNED and its uses.

src/deoptimizer.h

Index: src/deoptimizer.h
diff --git a/src/deoptimizer.h b/src/deoptimizer.h
index 5d401deedd6c8d9f06c15b7f9b61a3f352680176..4bbb8af5a5c1771cdcbb007e8852ac37f7ce1993 100644
--- a/src/deoptimizer.h
+++ b/src/deoptimizer.h
@@ -17,19 +17,15 @@ namespace internal {
 
 
 static inline double read_double_value(Address p) {
-#ifdef V8_HOST_CAN_READ_UNALIGNED
-  return Memory::double_at(p);
-#else  // V8_HOST_CAN_READ_UNALIGNED
   // Prevent gcc from using load-double (mips ldc1) on (possibly)
   // non-64-bit aligned address.
   union conversion {
     double d;
     uint32_t u[2];
   } c;
-  c.u[0] = *reinterpret_cast<uint32_t*>(p);
-  c.u[1] = *reinterpret_cast<uint32_t*>(p + 4);
+  c.u[0] = Memory::uint32_at(p);

[Jakob Kummerow, 2014/09/12 11:08:44]

Since Memory::uint32_at does a reinterpret_cast<uint32_t*>, this is only safe
when p is 4-byte aligned. I understand that this is guaranteed by current
callers, but please add a comment and/or DCHECK to make it explicit.

[Sven Panne, 2014/09/12 13:12:08]

Even simpler: Just use memcpy...

+  c.u[1] = Memory::uint32_at(p + 4);
   return c.d;
-#endif  // V8_HOST_CAN_READ_UNALIGNED
 }