[PATCH] D24324: AMDGPU: Fix selection failure with dead AssertZext

[Matt Arsenault via llvm-commits]

arsenm created this revision.
arsenm added a reviewer: tstellarAMD.
arsenm added a subscriber: llvm-commits.
Herald added subscribers: nhaehnle, wdng, arsenm.

Remove the dead AssertZext or else the ValueType operand will
fail to select for some reason.


https://reviews.llvm.org/D24324

Files:
  lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
  test/CodeGen/AMDGPU/captured-frame-index.ll

Index: test/CodeGen/AMDGPU/captured-frame-index.ll
===================================================================
--- test/CodeGen/AMDGPU/captured-frame-index.ll
+++ test/CodeGen/AMDGPU/captured-frame-index.ll
@@ -163,4 +163,23 @@
   ret void
 }
 
+ at g1 = external addrspace(1) global i32*
+
+; This was leaving a dead node around resulting in failing to select
+; on the leftover AssertZext's ValueType operand.
+
+; GCN-LABEL: {{^}}cannot_select_assertzext_valuetype:
+; GCN: 	s_add_u32 s{{[0-9]+}}, s{{[0-9]+}}, g1 at GOTPCREL+4
+; GCN: v_mov_b32_e32 [[FI:v[0-9]+]], 0{{$}}
+; GCN: buffer_store_dword [[FI]]
+define void @cannot_select_assertzext_valuetype(i32 addrspace(1)* %out, i32 %idx) #0 {
+entry:
+  %b = alloca i32, align 4
+  %tmp1 = load volatile i32*, i32* addrspace(1)* @g1, align 4
+  %arrayidx = getelementptr inbounds i32, i32* %tmp1, i32 %idx
+  %tmp2 = load i32, i32* %arrayidx, align 4
+  store volatile i32* %b, i32* addrspace(1)* undef
+  ret void
+}
+
 attributes #0 = { nounwind }
Index: lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
+++ lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
@@ -1550,6 +1550,9 @@
 
         CurDAG->UpdateNodeOperands(M, makeArrayRef(NewOps, OpN));
       }
+
+      if (EffectiveFI->use_empty())
+        CurDAG->RemoveDeadNode(EffectiveFI.getNode());
     }
   }
 }


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