llvm dev - Aug 2013 - [LLVMdev] Making MipsOptimizeMathLibCalls generic

MipsOptimizeMathLibCalls.cpp converts:

  g = sqrt (f);

into:

  r1 = sqrt (f) readonly;
  if (g is a NaN)
    r2 = sqrt (f);
  g = phi (r1, r2)

I'd like to do the same on z.  Would it be OK to make this pass generic
and do the transformation whenever FSQRT isLegalOrCustom for the type?

If so, should it stay a separate pass, or should I merge it with
something else?

Thanks,
Richard

Ping.

Richard Sandiford <rsandifo at linux.vnet.ibm.com>
writes:
> MipsOptimizeMathLibCalls.cpp converts:
>
>   g = sqrt (f);
>
> into:
>
>   r1 = sqrt (f) readonly;
>   if (g is a NaN)
>     r2 = sqrt (f);
>   g = phi (r1, r2)
>
> I'd like to do the same on z.  Would it be OK to make this pass generic
> and do the transformation whenever FSQRT isLegalOrCustom for the type?
>
> If so, should it stay a separate pass, or should I merge it with
> something else?
>
> Thanks,
> Richard
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

Assuming it is okay to make this pass generic, I would consider running it
as the last IR pass (at the end of TargetPassConfig::addIRPasses).


On Fri, Aug 16, 2013 at 5:13 AM, Richard Sandiford <
rsandifo at linux.vnet.ibm.com> wrote:
> Ping.
>
> Richard Sandiford <rsandifo at linux.vnet.ibm.com> writes:
> > MipsOptimizeMathLibCalls.cpp converts:
> >
> >   g = sqrt (f);
> >
> > into:
> >
> >   r1 = sqrt (f) readonly;
> >   if (g is a NaN)
> >     r2 = sqrt (f);
> >   g = phi (r1, r2)
> >
> > I'd like to do the same on z.  Would it be OK to make this pass
generic
> > and do the transformation whenever FSQRT isLegalOrCustom for the type?
> >
> > If so, should it stay a separate pass, or should I merge it with
> > something else?
> >
> > Thanks,
> > Richard
> >
> > _______________________________________________
> > LLVM Developers mailing list
> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
> _______________________________________________
> 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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