Merge changes I9c3e680b,I56c1a4fd,I4eb84d2b

* changes:
  PR tree-optimization/48052
  PR tree-optimization/52563, tree-optimization/62173
  Cherry-pick: PR tree-optimization/65447
tree: 4b1a6fa23a1de80d370cd72261d9e88d2440d608
  1. gcc-4.8/
  2. gcc-4.9/
  3. build-gcc.sh
  4. build.py