[LLVMdev] How to do bitcast for double to <2 x double>

[zhi chen]

Thanks Mats. Yes, it currently leads to "Illegal BitCast". Can I change the
pInst directly to generate the code I want?

On Wed, Apr 15, 2015 at 2:13 PM, mats petersson <mats at planetcatfish.com>
wrote:

> So, you need to bitcast `pinst` to a pointer to Vector of double,
> since it (I hope for your sake) is a pointer to integer. What you are
> trying to do is bitcast a pointer into a vector, which probably will
> lead to an assert or "bad code that doesn't work".
>
> --
> Mats
>
> On 15 April 2015 at 21:57, zhi chen <zchenhn at gmail.com> wrote:
> > What I want to do is to change the pInst from : 2%= load double* %1,
> align 8
> > to 2% = load < 2 x double>* %1, align 16, where <2 x double> should be
> two
> > double identical double values that is same as the one in the previous
> > instruction
> >
> > Instruction* ScalarToVectorLoad(Instruction* pInst) {
> >   Value *loadValue = pInst->getOperand(0);
> >   Instruction *newLoad;   //this one should be 2% = load < 2 x double>*
> %1
> >
> >   BitCastInst *scalarToVector = new BitCastInst(loadValue,
> > VectorType::get(Type::getDoubleTy(currF->getContext()), 2),
> > "vectorizedLoad", pInst);
> >   newLoad = new LoadInst(); //to be implemented...
> >   return newLoad;
> > }
> >
> > On Wed, Apr 15, 2015 at 1:03 PM, mats petersson <mats at planetcatfish.com>
> > wrote:
> >>
> >> Create a type that is a "vector (array) of 2 double", and then a
> >> pointer to that. Now use bitcast your on double pointer to that
> >> pointer type you've created, and then create a load...
> >>
> >> If you need more help, it would help if you post the code you are
> working
> >> on...
> >>
> >> --
> >> Mats
> >>
> >> On 15 April 2015 at 19:51, zhi chen <zchenhn at gmail.com> wrote:
> >> > How can I write code to generate IR for:
> >> > %2 = bitcast double* %1 to <2 x double>*.
> >> > %3 = load <2 x double>* %2, align 16
> >> > Basically, it is similar to x86 _mm_load_pd1 intrinsics.
> >> >
> >> > Thanks,
> >> > Zhi
> >> >
> >> > _______________________________________________
> >> > LLVM Developers mailing list
> >> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> >> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >> >
> >
> >
>
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