[PATCH] D76107: AMDGPU: Don't handle kernarg.segment.ptr in functions

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

In D76107#1920799 <https://reviews.llvm.org/D76107#1920799>, @rampitec wrote:

> In D76107#1920749 <https://reviews.llvm.org/D76107#1920749>, @arsenm wrote:
>
> > In D76107#1920704 <https://reviews.llvm.org/D76107#1920704>, @rampitec wrote:
> >
> > > A trap would be better, we can easily spot it.
> >
> >
> >
> >
> > In D76107#1920704 <https://reviews.llvm.org/D76107#1920704>, @rampitec wrote:
> >
> > > A trap would be better, we can easily spot it.
> >
> >
> > A trap isn’t particularly different from the null dereference if you try to actually use it. I was leaning more towards a compile time error
>
>
> It is actually very different. A null pointer dereference means debugging, tracking the pointer, analyzing IR step by step until you see why was null emitted. A trap on the contrary is immediately visible in the ISA dump and immediately triggers the alarm, that compiler have spotted the code which should never been executed.


The trap adds extra complexity to the implementation since now the queue ptr needs to be passed to the function. This should probably be considered a backend internal intrinsic now, so I'm not sure it's worth the effort


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