[LLVMdev] Help!!!!Help!!!! " LLVM ERROR: Cannot select: 0x9fc9680: i32 = fp32_to_fp16 0x9fc0750 [ID=16] " problem!!!!!!!!!!!!!!!!!!

[yalong at multicorewareinc.com]

Hi Renato,
    Thank you your replying.    Yes, we are making a tool in order to generate MIPS IR by ARM asembler. The ir is  Hand-crafted. We want to realise NEON instruction "vcvtt.f16.f32" by llvm.     Yes, MIPS is not supported NEON, but the problem is not related with mips platform. I think this problem only relate with llc of llvm, so this problem is about convertion between half float and float.  The problem I don't understand is  if llvm support half float, how to convert float to half float.        Robin Lau


yalong at multicorewareinc.com
 From: Renato GolinDate: 2014-07-09 01:39To: yalong at multicorewareinc.comCC: Kevin Qin; llvmdevSubject: Re: [LLVMdev] Help!!!!Help!!!! " LLVM ERROR: Cannot select: 0x9fc9680: i32 = fp32_to_fp16 0x9fc0750 [ID=16] " problem!!!!!!!!!!!!!!!!!!On 9 July 2014 23:30, yalong at multicorewareinc.com
<yalong at multicorewareinc.com> wrote:
>     If I use fptrunc and bitcast realise NEON vcvtt ( I can sure, "fptrunc
> double %tmp to float" is right, but "fptrunc float %tmp to half" is wrong).
> My target platform is MIPS.
 
AFAIK, MIPS doesn't support NEON. But that doesn't explain your
problem, which is probably due to hand-crafted IR.
 
Can you provide the full IR, with header and everything? Also the
command line that you're using with the LLVM tool you're using to
compile (llc?lli?).
 
It'd also be good to know how you generated that IR in the frist
place. Was it a tool? A front-end? Hand-crafted?
 
cheers,
--renato

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