[llvm] r323582 - [GlobalISel][Legalizer] Convert the FP constants to the right APFloat type for G_FCONSTANT.

[Hans Wennborg via llvm-commits]

Merged in r323742.

On Mon, Jan 29, 2018 at 7:45 PM, Amara Emerson <aemerson at apple.com> wrote:

> Hi Hans,
>
> Can we merge this into 6.0 please.
>
> Thanks,
> Amara
>
> > On Jan 26, 2018, at 11:07 PM, Amara Emerson via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
> >
> > Author: aemerson
> > Date: Fri Jan 26 23:07:20 2018
> > New Revision: 323582
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=323582&view=rev
> > Log:
> > [GlobalISel][Legalizer] Convert the FP constants to the right APFloat
> type for G_FCONSTANT.
> >
> > We weren't converting the immediate ConstantFP during legalization,
> which caused
> > the wrong bit patterns to be emitted for half type FP constants.
> >
> > Fixes PR36106.
> >
> > Modified:
> >    llvm/trunk/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
> >    llvm/trunk/test/CodeGen/AArch64/GlobalISel/legalize-constant.mir
> >
> > Modified: llvm/trunk/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
> CodeGen/GlobalISel/LegalizerHelper.cpp?rev=323582&r1=323581&r2=323582&
> view=diff
> > ============================================================
> ==================
> > --- llvm/trunk/lib/CodeGen/GlobalISel/LegalizerHelper.cpp (original)
> > +++ llvm/trunk/lib/CodeGen/GlobalISel/LegalizerHelper.cpp Fri Jan 26
> 23:07:20 2018
> > @@ -715,7 +715,24 @@ LegalizerHelper::widenScalar(MachineInst
> >   }
> >   case TargetOpcode::G_FCONSTANT: {
> >     unsigned DstExt = MRI.createGenericVirtualRegister(WideTy);
> > -    MIRBuilder.buildFConstant(DstExt, *MI.getOperand(1).getFPImm());
> > +    const ConstantFP *CFP = MI.getOperand(1).getFPImm();
> > +    APFloat Val = CFP->getValueAPF();
> > +    LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
> > +    auto LLT2Sem = [](LLT Ty) {
> > +      switch (Ty.getSizeInBits()) {
> > +      case 32:
> > +        return &APFloat::IEEEsingle();
> > +        break;
> > +      case 64:
> > +        return &APFloat::IEEEdouble();
> > +        break;
> > +      default:
> > +        llvm_unreachable("Unhandled fp widen type");
> > +      }
> > +    };
> > +    bool LosesInfo;
> > +    Val.convert(*LLT2Sem(WideTy), APFloat::rmTowardZero, &LosesInfo);
> > +    MIRBuilder.buildFConstant(DstExt, *ConstantFP::get(Ctx, Val));
> >     MIRBuilder.buildFPTrunc(MI.getOperand(0).getReg(), DstExt);
> >     MI.eraseFromParent();
> >     return Legalized;
> >
> > Modified: llvm/trunk/test/CodeGen/AArch64/GlobalISel/legalize-
> constant.mir
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
> CodeGen/AArch64/GlobalISel/legalize-constant.mir?rev=
> 323582&r1=323581&r2=323582&view=diff
> > ============================================================
> ==================
> > --- llvm/trunk/test/CodeGen/AArch64/GlobalISel/legalize-constant.mir
> (original)
> > +++ llvm/trunk/test/CodeGen/AArch64/GlobalISel/legalize-constant.mir
> Fri Jan 26 23:07:20 2018
> > @@ -75,7 +75,7 @@ body: |
> >     ; CHECK: %w0 = COPY [[C]](s32)
> >     ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_FCONSTANT double 2.000000e+00
> >     ; CHECK: %x0 = COPY [[C1]](s64)
> > -    ; CHECK: [[C2:%[0-9]+]]:_(s32) = G_FCONSTANT half 0xH0000
> > +    ; CHECK: [[C2:%[0-9]+]]:_(s32) = G_FCONSTANT float 0.000000e+00
> >     ; CHECK: [[FPTRUNC:%[0-9]+]]:_(s16) = G_FPTRUNC [[C2]](s32)
> >     ; CHECK: [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[FPTRUNC]](s16)
> >     ; CHECK: %w0 = COPY [[ANYEXT]](s32)
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20180130/efe99d6f/attachment.html>