[PATCH] D77777: [nvptx] Add `nvvm.texsurf.handle` internalizer.

[David Majnemer via Phabricator via cfe-commits]

majnemer added a comment.

In D77777#1975618 <https://reviews.llvm.org/D77777#1975618>, @hliao wrote:

> In D77777#1975406 <https://reviews.llvm.org/D77777#1975406>, @tra wrote:
>
> > In D77777#1975178 <https://reviews.llvm.org/D77777#1975178>, @hliao wrote:
> >
> > > the 1st argument in `llvm.nvvm.texsurf.hande.internal` or the 2nd one in `llvm.nvvm.texsurf.handle` must be kept as an immediate or constant value, i.e. that global variable. However, optimizations will find common code in the following
> > >
> > >   if (cond) {
> > >     %hnd = texsurf.handle.internal(@tex1);
> > >   } else {
> > >     %hnd = texsurf.handle.internal(@tex2)
> > >   }
> > >   = use(%hnd)
> > >
> > >
> > > and hoist or sink it into
> > >
> > >   if (cond) {
> > >     %ptr = @tex1;
> > >   } else {
> > >     %ptr = @tex2;
> > >   }
> > >   %hnd = texsurf.handle.intenal(%ptr);
> > >   = use(%hnd)
> > >
> > >
> > > The backend cannot handle non immediate operand in `texsurf.handle`. The similar thing happens to `read.register` as well as it also assumes its argument is always an immediate value.
> >
> >
> > I wonder if we can use `token` types to represent the handle? https://reviews.llvm.org/D11861
> >  @majnemer -- would this use case be suitable for the `token` type?
>
>
> If we still could make PHI over token, it canont serve this purpose. Check `llvm::canReplaceOperandWithVariable` for operand for details.


It is not possible to PHI a token value. Token values disable the call to canReplaceOperandWithVariable.


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https://reviews.llvm.org/D77777