Displaying 2 results from an estimated 2 matches for "lcpxx".
2014 Sep 19
4
[LLVMdev] Please benchmark new x86 vector shuffle lowering, planning to make it the default very soon!
...'t observed any significant regression in our internal codebase.
In one particular case I observed a slowdown (around 1%); here is what
I found when investigating on this slowdown.
1. With the new shuffle lowering, there is one case where we end up
producing the following sequence:
vmovss .LCPxx(%rip), %xmm1
vxorps %xmm0, %xmm0, %xmm0
vblendps $1, %xmm1, %xmm0, %xmm0
Before, we used to generate a simpler:
vmovss .LCPxx(%rip), %xmm1
In this particular case, the 'vblendps' is redundant since the vmovss
would zero the upper bits in %xmm1. I am not sure why we get this
poor-...
2014 Sep 10
13
[LLVMdev] Please benchmark new x86 vector shuffle lowering, planning to make it the default very soon!
On Tue, Sep 9, 2014 at 11:39 PM, Chandler Carruth <chandlerc at google.com> wrote:
> Awesome, thanks for all the information!
>
> See below:
>
> On Tue, Sep 9, 2014 at 6:13 AM, Andrea Di Biagio <andrea.dibiagio at gmail.com>
> wrote:
>>
>> You have already mentioned how the new shuffle lowering is missing
>> some features; for example, you explicitly