Backport google/gcc-4_9-branch:r232957 for PR/69403.

Test:
1. Verified bug in
https://code.google.com/p/chrome-os-partner/issues/detail?id=49496
2. Build oak board

BUG=chromium:49496
TEST=See above description

Change-Id: Ibd93ed16d3940fc2bbe7445d0a44b4050d498ae4
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/google/gcc-4_9-mobile@232960 138bc75d-0d04-0410-961f-82ee72b054a4
Reviewed-on: https://chromium-review.googlesource.com/324617
Commit-Ready: Han Shen <shenhan@chromium.org>
Tested-by: Han Shen <shenhan@chromium.org>
Reviewed-by: Caroline Tice <cmtice@chromium.org>
Reviewed-by: Han Shen <shenhan@chromium.org>
4 files changed