tree 6010aff2211c497a0b42531216d829a92ae31a93
parent d7ee972862e2952ed895497eba5760c738a7da11
author Jan Voung <jvoung@chromium.org> 1406739963 -0700
committer Jan Voung <jvoung@chromium.org> 1406739963 -0700

Fix bug when atomic load is fused with an arith op (and not in the entry BB)

Normally, the FakeUse for preserving the atomic load ends
up on the load's Dest. However, for fused load+add, the load
is deleted, and its Dest is no longer defined. This trips
up the liveness analysis when it happens on a non-entry
block. So the FakeUse should be for the add's dest instead,
in that case.

We have no access to the add, so introduce a
getLastInserted() helper. A couple of ways to do that:
- modify insert() to track explicitly
- rewind from Next one step

Either that, or we disable the fusing for atomic loads.

BUG=  https://code.google.com/p/nativeclient/issues/detail?id=3882
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/417353003