rampitec wrote:
> Test case:
>
> ```
> @lds.0 = internal addrspace(3) global [64 x float] poison, align 16
> @lds.1 = internal addrspace(3) global [64 x float] poison, align 16
>
> declare void @llvm.amdgcn.raw.buffer.load.lds(<4 x i32> %rsrc, ptr
> addrspace(3) nocapture, i32 %size, i32 %voffset, i32 %soffset, i32 %offset,
> i32 %aux)
>
> define amdgpu_kernel void @f(<4 x i32> %rsrc, i32 %i1, i32 %i2, ptr
> addrspace(1) %out, ptr addrspace(3) %ptr) {
> main_body:
> call void @llvm.amdgcn.raw.buffer.load.lds(<4 x i32> %rsrc, ptr
> addrspace(3) @lds.0, i32 4, i32 0, i32 0, i32 0, i32 0)
> call void @llvm.amdgcn.raw.buffer.load.lds(<4 x i32> %rsrc, ptr
> addrspace(3) %ptr, i32 4, i32 0, i32 0, i32 0, i32 0)
> %gep.0 = getelementptr float, ptr addrspace(3) @lds.0, i32 %i1
> %gep.1 = getelementptr float, ptr addrspace(3) @lds.1, i32 %i2
> %val.0 = load volatile float, ptr addrspace(3) %gep.0, align 4
> %val.1 = load volatile float, ptr addrspace(3) %gep.1, align 4
> %out.gep.1 = getelementptr float, ptr addrspace(1) %out, i32 1
> store float %val.0, ptr addrspace(1) %out
> store float %val.1, ptr addrspace(1) %out.gep.1
> ret void
> }
> ```
>
> Generates:
>
> ```
> s_load_dwordx8 s[4:11], s[0:1], 0x24
> s_load_dword s2, s[0:1], 0x44
> s_mov_b32 m0, 0
> v_mov_b32_e32 v2, 0
> s_waitcnt lgkmcnt(0)
> buffer_load_dword off, s[4:7], 0 lds
> s_mov_b32 m0, s2
> s_lshl_b32 s0, s8, 2
> buffer_load_dword off, s[4:7], 0 lds
> s_lshl_b32 s1, s9, 2
> v_mov_b32_e32 v0, s0
> v_mov_b32_e32 v1, s1
> s_waitcnt vmcnt(1)
> ds_read_b32 v0, v0
> s_waitcnt vmcnt(0)
> ds_read_b32 v1, v1 offset:256
> s_waitcnt lgkmcnt(0)
> global_store_dwordx2 v2, v[0:1], s[10:11]
> s_endpgm
> ```
>
> The `s_waitcnt vmcnt(1)` seems incorrect, because the second
> buffer-load-to-lds might clobber `@lds.0`.
This is still correct, pointer argument cannot alias module global. A pointer
argument to a kernel is an LDS external requested by the host side, and host
cannot see module LDS.
https://github.com/llvm/llvm-project/pull/74537
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
