[llvm-commits] [llvm] r44874 - /llvm/trunk/lib/CodeGen/MachineLICM.cpp

[Bill Wendling]

On Dec 12, 2007 1:38 AM, Evan Cheng <evan.cheng at apple.com> wrote:
>
>
> On Dec 11, 2007, at 11:40 AM, Bill Wendling <isanbard at gmail.com> wrote:
>
> > Author: void
> > Date: Tue Dec 11 13:40:06 2007
> > New Revision: 44874
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=44874&view=rev
> > Log:
> > Blark! How in the world did this work without this?!
>
> Is this just cosmetic changes? I am sure I see why this is better?
> Just curious.
>
This is the part of the patch that has the "real" change. The rest are cosmetic.

  // Get our Loop information...
  LI = &getAnalysis<MachineLoopInfo>();
  DT = &getAnalysis<MachineDominatorTree>();

+  MapVirtualRegisterDefs();
+

> One thing that is some what annoying to me is if LICM is after live
> variables then it won't need to compute vreg def info or liveness
> info. I wonder if it is possible to move the pass after live variables?
>
I'm sure I could move it, but as Chris asked, isn't it trivial to get
this information anyway? Also, I'm kind of hesitant to put so much
effort into compile-time performance issues when it doesn't even have
partial (let alone full) functionality right now. We don't know what
impact any of those optimizations have or if they are necessary yet.
:-)

-bw