[llvm-commits] [llvm] r147719 - /llvm/trunk/lib/CodeGen/BranchFolding.cpp

[Jakob Stoklund Olesen]

On Jan 6, 2012, at 7:35 PM, Evan Cheng wrote:

> Author: evancheng
> Date: Fri Jan  6 21:35:48 2012
> New Revision: 147719
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=147719&view=rev
> Log:
> Revert part of r147716. Looks like x87 instructions kill markers are all messed
> up so branch folding pass can't use the scavenger. :-(  This doesn't breaks
> anything currently. It just means targets which do not carefully update kill
> markers cannot run post-ra scheduler (not new, it has always been the case).
> 
> We should fix this at some point since it's really hacky.

Ugh, yes. The x87 ST registers are a mess.

They should really be marked as reserved because it doesn't make sense to track liveness of stack positions.

Unfortunately, that disables some dead code elimination around x87 inline asm, IIRC. I forget the exact problem.

/jakob