Revert "fix build warnings to compile with linaro -Ofast optimization"

This reverts commit ff6c858beb94e0e589c0cfebdd1c3617ad30b724.
Revert "fix build with Linaro GCC 4.9.1"

This reverts commit 83d764036915fd8b032af9a89dc3f04ef3e7dcf7.
Revert "fix build with Linaro GCC 4.9.1"

This reverts commit 4d6265260829e5b0cfa97c91f2c095918f276d9d.