A64: initialize members of MemOperand.

src/a64/assembler-a64-inl.h

Index: src/a64/assembler-a64-inl.h
diff --git a/src/a64/assembler-a64-inl.h b/src/a64/assembler-a64-inl.h
index 7cf3329ffba5dfe16e2f57db88bd6e7b1d07970d..7216c47dcd6178fd8622ca612aa4221251db3ca9 100644
--- a/src/a64/assembler-a64-inl.h
+++ b/src/a64/assembler-a64-inl.h
@@ -393,7 +393,8 @@ Operand Operand::UntagSmiAndScale(Register smi, int scale) {
 
 
 MemOperand::MemOperand(Register base, ptrdiff_t offset, AddrMode addrmode)
-  : base_(base), regoffset_(NoReg), offset_(offset), addrmode_(addrmode) {
+  : base_(base), regoffset_(NoReg), offset_(offset), addrmode_(addrmode),
+    shift_(NO_SHIFT), extend_(NO_EXTEND), shift_amount_(0) {
   ASSERT(base.Is64Bits() && !base.IsZero());
 }