[llvm-dev] KNL Vectorization with larger vector width

[hameeza ahmed via llvm-dev]

Hello,
Do i need to change following function;

unsigned X86TTIImpl::getNumberOfRegisters(bool Vector) {
  if (Vector && !ST->hasSSE1())
    return 0;

  if (ST->is64Bit()) {
    if (Vector && ST->hasAVX512())
      return 32;
    return 16;
  }
  return 8;
}

to

if (ST->is2048Bit()) {
    if (Vector && ST->hasAVX512())
      return 1024;
    return 512;
  }
  return 256;


please help...

On Tue, Jul 24, 2018 at 5:05 AM, hameeza ahmed <hahmed2305 at gmail.com> wrote:

> Thank You.
> Right now to see the effect i did following changes;
>
> unsigned X86TTIImpl::getRegisterBitWidth(bool Vector) {
>   if (Vector) {
>     if (ST->hasAVX512())
>       return 65536;
>
> here i changed 512 to 65536. Then in loopvectorize.cpp i did following;
>
>  assert(MaxVectorSize <= 2048 && "Did not expect to pack so many elements"
>                                 " into one vector!");
>
> changed 64 to 2048.
>
> It runs fine. I can see in IR <2048xi32> or <1024xi64> emission.
>
> But I cannot see the vector mix like in default knl if iterations=15 we
> see 1<8xi32> and rest scalar. so here when i keep iteration=2047 i get all
> scalar why is that so? similarly in polly as well i cant see vector mixes
> like its happening for KNL it emits <v16i32>, <v8i32>,<v4i32>...so here it
> should emit recursively like <v2048i32> <v1024i32> <v512i32>.....<v32i32>
>
> how to do this?
>
> What am i missing here?
> what further changes do i need to make?
>
> Please help...
>
>
>
>
>
>
> On Tue, Jul 24, 2018 at 1:52 AM, Friedman, Eli <efriedma at codeaurora.org>
> wrote:
>
>> On 7/23/2018 12:40 PM, hameeza ahmed wrote:
>>
>>> Thank You. I got it. Version issue.
>>>
>>> TTI.getRegisterBitWidth(true)
>>>
>>> How to put my target machine info in TTI?
>>>
>>
>> Each target has an implementation, e.g. X86TTIImpl::getRegisterBitWidth.
>>
>>
>> -Eli
>>
>> --
>> Employee of Qualcomm Innovation Center, Inc.
>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
>> Linux Foundation Collaborative Project
>>
>>
>
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