added two more tests that result in no waitcnt:

- fence does not specify LDS
- fence is not a release

Author: ssahasra

llvm/test/CodeGen/AMDGPU/insert-waitcnts-fence-soft.mir

@@ -84,6 +84,46 @@ body:             |
 
 ...
 
+# Expected no vmcnt since the fence does not specify LDS
+
+---
+name: dma_then_no_lds
+body:             |
+  bb.0:
+    ; GCN-LABEL: name: dma_then_no_lds
+    ; GCN: S_WAITCNT 0
+    ; GCN-NEXT: BUFFER_LOAD_DWORD_LDS_IDXEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr4, 4, 0, 0, implicit $exec, implicit $m0 :: (load (s32) from `ptr addrspace(1) poison` + 4, addrspace 1), (store (s32) into `ptr addrspace(3) poison` + 4, addrspace 3)
+    ; GCN-NEXT: $vgpr2 = GLOBAL_LOAD_DWORD $vgpr4_vgpr5, 0, 0, implicit $exec
+    ; GCN-NEXT: $vgpr1 = V_ADD_F32_e32 $vgpr1, $vgpr1, implicit $mode, implicit $exec
+    ; GCN-NEXT: S_ENDPGM 0
+    BUFFER_LOAD_DWORD_LDS_IDXEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr4, 4, 0, 0, implicit $exec, implicit $m0 :: (load (s32) from `ptr addrspace(1) poison` + 4), (store (s32) into `ptr addrspace(3) poison` + 4)
+    $vgpr2 = GLOBAL_LOAD_DWORD $vgpr4_vgpr5, 0, 0, implicit $exec
+    S_WAITCNT_FENCE_soft 5, 5, 5
+    $vgpr1 = V_ADD_F32_e32 $vgpr1, $vgpr1, implicit $mode, implicit $exec
+    S_ENDPGM 0
+
+...
+
+# Expected no vmcnt since the fence is not a release
+
+---
+name: no_release
+body:             |
+  bb.0:
+    ; GCN-LABEL: name: no_release
+    ; GCN: S_WAITCNT 0
+    ; GCN-NEXT: BUFFER_LOAD_DWORD_LDS_IDXEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr4, 4, 0, 0, implicit $exec, implicit $m0 :: (load (s32) from `ptr addrspace(1) poison` + 4, addrspace 1), (store (s32) into `ptr addrspace(3) poison` + 4, addrspace 3)
+    ; GCN-NEXT: $vgpr2 = GLOBAL_LOAD_DWORD $vgpr4_vgpr5, 0, 0, implicit $exec
+    ; GCN-NEXT: $vgpr1 = V_ADD_F32_e32 $vgpr1, $vgpr1, implicit $mode, implicit $exec
+    ; GCN-NEXT: S_ENDPGM 0
+    BUFFER_LOAD_DWORD_LDS_IDXEN $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr4, 4, 0, 0, implicit $exec, implicit $m0 :: (load (s32) from `ptr addrspace(1) poison` + 4), (store (s32) into `ptr addrspace(3) poison` + 4)
+    $vgpr2 = GLOBAL_LOAD_DWORD $vgpr4_vgpr5, 0, 0, implicit $exec
+    S_WAITCNT_FENCE_soft 4, 5, 15
+    $vgpr1 = V_ADD_F32_e32 $vgpr1, $vgpr1, implicit $mode, implicit $exec
+    S_ENDPGM 0
+
+...
+
 # Expected no vmcnt since direct loads to LDS don't matter at wavefront scope.
 
 ---