List of items:
  1. Avoid zero-extending for subsequent 32-bit operations if current operation does not change upper 32-bit or does zero-extending.
  2. Match complex address mode for binary operation where possible (eg. use Add R,MEM).
  3. Detect instruction forms in selector. Eg. kAllowRRR, kAllowRM
  4. Optimize sequence for Int32MulWithOverflow, Int32Div, etc.
  5. Remove Not32/Not64 which is the same as XOR

R=bjaideep@ca.ibm.com, joransiu@ca.ibm.com
BUG=

Review-Url: https://codereview.chromium.org/2649113007
Cr-Commit-Position: refs/heads/master@{#42669}