[PATCH] D21873: RegisterScavenger: Introduce backward() mode.

[Matthias Braun via llvm-commits]

MatzeB created this revision.
MatzeB added a reviewer: qcolombet.
MatzeB added a subscriber: llvm-commits.
MatzeB set the repository for this revision to rL LLVM.
Herald added a subscriber: mcrosier.

This adds two pieces:
- RegisterScavenger:::enterBasicBlockEnd() which behaves similar to
  enterBasicBlock() but starts tracking at the end of the basic block.
- A RegisterScavenger::backward() method. It is subtly different
  from the existing unprocess() method which only considers uses with
  the kill flag set: If a value is dead at the end of a basic block with
  a last use inside the basic block, unprocess() will fail to mark it as
  live. However we cannot change/fix this behaviour because unprocess()
  needs to perform the exact reverse operation of forward().

Note: This is part of a patch series to make FrameLowering/PEI independent of kill flags. Patches building upon this are upcoming. I will not commit this until some of the patches depending on this are accepted.

Repository:
  rL LLVM

http://reviews.llvm.org/D21873

Files:
  include/llvm/CodeGen/RegisterScavenging.h
  lib/CodeGen/RegisterScavenging.cpp

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D21873.62306.patch
Type: text/x-patch
Size: 6402 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20160629/67a9ac92/attachment.bin>