Use memcpy to read double value in the deoptimizer.

src/deoptimizer.h

Index: src/deoptimizer.h
diff --git a/src/deoptimizer.h b/src/deoptimizer.h
index 602a21a0e20b199e7ca9a229b79c0be5be9c4783..1b6e814661f261f1b8cbd7976c55d8a7f2fcd1eb 100644
--- a/src/deoptimizer.h
+++ b/src/deoptimizer.h
@@ -17,17 +17,9 @@ namespace internal {
 
 
 static inline double read_double_value(Address p) {
-  // Prevent gcc from using load-double (mips ldc1) on (possibly)
-  // non-64-bit aligned address.
-  // We assume that the address is 32-bit aligned.
-  DCHECK(IsAligned(reinterpret_cast<intptr_t>(p), kInt32Size));
-  union conversion {
-    double d;
-    uint32_t u[2];
-  } c;
-  c.u[0] = Memory::uint32_at(p);
-  c.u[1] = Memory::uint32_at(p + 4);
-  return c.d;
+  double d;
+  memcpy(&d, p, sizeof(d));
+  return d;
 }