[llvm] [AMDGPU] Precommit test for LDS DMA waitcounts. NFC. (PR #75240)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Stanislav Mekhanoshin (rampitec)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/75240.diff


1 Files Affected:

- (added) llvm/test/CodeGen/AMDGPU/lds-dma-waits.ll (+78) 


``````````diff
diff --git a/llvm/test/CodeGen/AMDGPU/lds-dma-waits.ll b/llvm/test/CodeGen/AMDGPU/lds-dma-waits.ll
new file mode 100644
index 00000000000000..688f0314f7d8f4
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/lds-dma-waits.ll
@@ -0,0 +1,78 @@
+; RUN: llc -march=amdgcn -mcpu=gfx900 < %s | FileCheck %s --check-prefixes=GCN,GFX9
+; RUN: llc -march=amdgcn -mcpu=gfx1030 < %s | FileCheck %s --check-prefixes=GCN,GFX10
+
+ at lds.0 = internal addrspace(3) global [64 x float] poison, align 16
+ at 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)
+declare void @llvm.amdgcn.global.load.lds(ptr addrspace(1) nocapture %gptr, ptr addrspace(3) nocapture %lptr, i32 %size, i32 %offset, i32 %aux)
+
+; FIXME: vmcnt(0) is too strong, it shall use vmcnt(2) before the first
+;        ds_read_b32 and vmcnt(0) before the second.
+; FIXME: GFX10 does not get a waitcount at all.
+
+; GCN-LABEL: {{^}}buffer_load_lds_dword_2_arrays:
+; GCN-COUNT-4: buffer_load_dword
+; GFX9: s_waitcnt vmcnt(0)
+
+; FIXME:
+; GFX10-NOT: s_waitcnt
+
+; GCN: ds_read_b32
+
+; FIXME:
+; GCN-NOT: s_waitcnt
+
+; GCN: ds_read_b32
+define amdgpu_kernel void @buffer_load_lds_dword_2_arrays(<4 x i32> %rsrc, i32 %i1, i32 %i2, ptr addrspace(1) %out) {
+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) @lds.0, i32 4, i32 4, i32 0, i32 0, i32 0)
+  call void @llvm.amdgcn.raw.buffer.load.lds(<4 x i32> %rsrc, ptr addrspace(3) @lds.1, i32 4, i32 8, i32 0, i32 0, i32 0)
+  call void @llvm.amdgcn.raw.buffer.load.lds(<4 x i32> %rsrc, ptr addrspace(3) @lds.1, i32 4, i32 12, 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 float, ptr addrspace(3) %gep.0, align 4
+  call void @llvm.amdgcn.wave.barrier()
+  %val.1 = load float, ptr addrspace(3) %gep.1, align 4
+  %tmp.0 = insertelement <2 x float> undef, float %val.0, i32 0
+  %res = insertelement <2 x float> %tmp.0, float %val.1, i32 1
+  store <2 x float> %res, ptr addrspace(1) %out
+  ret void
+}
+
+; On gfx9 if there is a pending FLAT operation, and this is a VMem or LGKM
+; waitcnt and the target can report early completion, then we need to force a waitcnt 0.
+
+; GCN-LABEL: {{^}}global_load_lds_dword_2_arrays:
+; GCN-COUNT-4: global_load_dword
+; GFX9: s_waitcnt vmcnt(0)
+; GFX9-COUNT-2: ds_read_b32
+
+; FIXME:
+; GFX10-NOT: s_waitcnt
+
+; GFX10: ds_read_b32
+
+; FIXME:
+; GFX10-NOT: s_waitcnt
+
+; GFX10: ds_read_b32
+define amdgpu_kernel void @global_load_lds_dword_2_arrays(ptr addrspace(1) nocapture %gptr, i32 %i1, i32 %i2, ptr addrspace(1) %out) {
+main_body:
+  call void @llvm.amdgcn.global.load.lds(ptr addrspace(1) %gptr, ptr addrspace(3) @lds.0, i32 4, i32 0, i32 0)
+  call void @llvm.amdgcn.global.load.lds(ptr addrspace(1) %gptr, ptr addrspace(3) @lds.0, i32 4, i32 4, i32 0)
+  call void @llvm.amdgcn.global.load.lds(ptr addrspace(1) %gptr, ptr addrspace(3) @lds.1, i32 4, i32 8, i32 0)
+  call void @llvm.amdgcn.global.load.lds(ptr addrspace(1) %gptr, ptr addrspace(3) @lds.1, i32 4, i32 12, 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 float, ptr addrspace(3) %gep.0, align 4
+  call void @llvm.amdgcn.wave.barrier()
+  %val.1 = load float, ptr addrspace(3) %gep.1, align 4
+  %tmp.0 = insertelement <2 x float> undef, float %val.0, i32 0
+  %res = insertelement <2 x float> %tmp.0, float %val.1, i32 1
+  store <2 x float> %res, ptr addrspace(1) %out
+  ret void
+}
+
+declare void @llvm.amdgcn.wave.barrier()

``````````

</details>


https://github.com/llvm/llvm-project/pull/75240