[llvm-commits] [llvm] r99436 - in /llvm/trunk/lib/Target/ARM: ARMInstrFormats.td ARMInstrInfo.td ARMInstrVFP.td ARMSubtarget.cpp ARMSubtarget.h

[Jim Grosbach]

On Mar 25, 2010, at 8:42 AM, Anton Korobeynikov wrote:

> Hello, Jim
> 
>> Have you run benchmarks on other variants showing the instructions to be a win? This looks to be a pretty fundamental flaw in the VFP unit.
> This is pretty expected on A8, where VFP unit is not pipelined at all
> (aka "VFP-lite").
> However, for example, on A9 VFP is pipelined and these instructions
> should behave properly.


This isn't expected behaviour on A8 at all. There are additional stalls beyond what can be explained by not being pipelined.