[PATCH] D130729: [InferAddressSpaces] [AMDGPU] Add inference for flat_atomic intrinsics

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

rampitec added inline comments.


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Comment at: llvm/test/CodeGen/AMDGPU/gep-const-offset-address-space.ll:158
+; CHECK-NEXT:    v_pk_mov_b32 v[0:1], s[6:7], s[6:7] op_sel:[0,1]
+; CHECK-NEXT:    global_atomic_add_f64 v2, v[0:1], s[0:1]
+; CHECK-NEXT:    s_endpgm
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arsenm wrote:
> rampitec wrote:
> > arsenm wrote:
> > > jrbyrnes wrote:
> > > > arsenm wrote:
> > > > > I wouldn't expect this transform to happen. I would expect to emit the flat instruction for the flat atomic despite the address space
> > > > Not for this PHI test in particular, but for all these tests in which we lower to a global_atomic, right? 
> > > Yes. I expect the flat atomic intrinsic to give the flat instruction regardless of address space
> > If we know its AS exactly why not to do it? Especially that we are widely using code specialization with AS checking when flat atomic is unavailable.
> I thought the whole reason we had these address space specific intrinsics in the first place was because of the painfully divergent behaviors in the instructions
Added @b-sumner. There is some divergence between DS and VMEM, I do not recall global vs flat within the same GPU. But then I believe these intrinsics exist to use what the target can offer, so mostly because of the divergence between GPUs itself.


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  https://reviews.llvm.org/D130729/new/

https://reviews.llvm.org/D130729