LiveRegUnits: Add accumulateBackward() function
Re-Commit r292543 with a fix for the situation when the chain end is
MBB.end().
This function can be used to accumulate the set of all read and modified
register in a sequence of instructions.
Use this code in AArch64A57FPLoadBalancing::scavengeRegister() to prove
the concept.
- The AArch64A57LoadBalancing code is using a backwards analysis now
which is irrespective of kill flags. This is the main motivation for
this change.
Differential Revision: http://reviews.llvm.org/D22082
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292705
91177308-0d34-0410-b5e6-
96231b3b80d8