[LLVMdev] X86TargetLowering::LowerToBT

[Quentin Colombet]

On Jan 22, 2015, at 3:29 PM, Chris Sears <chris.sears at gmail.com> wrote:

> The status quo is:
> 
> a) 40b REX+BT instruction for the 64b case
> b) 48b TEST for the 32b case
> c) unless it's small TEST
> 
> You are currently paying a 16b penalty for TEST vs BT in the 32b case.
> That may be worth testing the -Os flag.

Seems like a must do for -Oz at least.

Cheers,
Q. 

> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150122/8ec4832d/attachment.html>