llvm dev - Dec 2014 - [LLVMdev] Cannot split vector result of AVX intrinsic _mm256_rsqrt_ps

I'm getting this on LLVM trunk:

SplitVectorResult #0: 0x27e6250: v8f32 = llvm.x86.avx.rsqrt.ps.256
0x2739310, 0x2739420 [ORD=16] [ID=0]
LLVM ERROR: Do not know how to split the result of this operator!
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Oddly, when I build the same code without -flto I don't see this issue.

I see a similar bug was reported over a year ago and has had no
activity (though it doesn't use LTO):
http://llvm.org/bugs/show_bug.cgi?id=17909

This sounds like the somehow the frontend is allowing the intrinsic to be
used but the backend thinks it not legal and is trying to split the vector
type to a legal type.

Can you provide your source and command line.

On Sat, Dec 13, 2014 at 2:17 PM, Steven Noonan <steven at uplinklabs.net>
wrote:
>
> I'm getting this on LLVM trunk:
>
> SplitVectorResult #0: 0x27e6250: v8f32 = llvm.x86.avx.rsqrt.ps.256
> 0x2739310, 0x2739420 [ORD=16] [ID=0]
> LLVM ERROR: Do not know how to split the result of this operator!
> clang: error: linker command failed with exit code 1 (use -v to see
> invocation)
>
> Oddly, when I build the same code without -flto I don't see this issue.
>
> I see a similar bug was reported over a year ago and has had no
> activity (though it doesn't use LTO):
> http://llvm.org/bugs/show_bug.cgi?id=17909
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>

-- 
~Craig
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20141213/b5802837/attachment.html>

Steven's problem sounds similar to:
http://llvm.org/bugs/show_bug.cgi?id=19416

The cpu/feature flags aren't being passed through correctly with -flto?

In bug 17909, the run script shows "-target-cpu core2" for code that
includes AVX.

Is this expected behavior?

$ cat avx.ll
define <4 x double> @wrap_a_round(<4 x double> %a) {
  %round = tail call <4 x double> @llvm.x86.avx.round.pd.256(<4 x
double>
%a, i32 0)
  ret <4 x double> %round
}

declare <4 x double> @llvm.x86.avx.round.pd.256(<4 x double>, i32)

$ ./llc -mcpu=core2 avx.ll
SplitVectorResult #0: 0x7fdc29849970: v4f64 = llvm.x86.avx.round.pd.256
0x7fdc29849750, 0x7fdc29849640, 0x7fdc29849860 [ORD=2] [ID=0]

LLVM ERROR: Do not know how to split the result of this operator!



On Sat, Dec 13, 2014 at 5:49 PM, Craig Topper <craig.topper at gmail.com>
wrote:
> This sounds like the somehow the frontend is allowing the intrinsic to be
> used but the backend thinks it not legal and is trying to split the vector
> type to a legal type.
>
> Can you provide your source and command line.
>
> On Sat, Dec 13, 2014 at 2:17 PM, Steven Noonan <steven at
uplinklabs.net>
> wrote:
>>
>> I'm getting this on LLVM trunk:
>>
>> SplitVectorResult #0: 0x27e6250: v8f32 = llvm.x86.avx.rsqrt.ps.256
>> 0x2739310, 0x2739420 [ORD=16] [ID=0]
>> LLVM ERROR: Do not know how to split the result of this operator!
>> clang: error: linker command failed with exit code 1 (use -v to see
>> invocation)
>>
>> Oddly, when I build the same code without -flto I don't see this
issue.
>>
>> I see a similar bug was reported over a year ago and has had no
>> activity (though it doesn't use LTO):
>> http://llvm.org/bugs/show_bug.cgi?id=17909
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>
>
>
> --
> ~Craig
>
> _______________________________________________
> 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/20150106/89bf9a54/attachment.html>