R600: Fix asserts related to constant initializers

This would assert if a constant address space was extern
and therefore didn't have an initializer. If the initializer
was undef, it would hit the unreachable unhandled initializer case.

An extern global should never really occur since we don't have
machine linking, but bugpoint likes to remove initializers.

llvm-svn: 210967

2 files changed, 40 insertions, 5 deletions

diff --git a/llvm/lib/Target/R600/AMDGPUISelLowering.cpp b/llvm/lib/Target/R600/AMDGPUISelLowering.cpp
index 3ea789da5aa..7867de23fd2 100644
--- a/llvm/lib/Target/R600/AMDGPUISelLowering.cpp
+++ b/llvm/lib/Target/R600/AMDGPUISelLowering.cpp
@@ -655,6 +655,14 @@ SDValue AMDGPUTargetLowering::LowerConstantInitializer(const Constant* Init,
     return DAG.getNode(ISD::TokenFactor, DL, MVT::Other, Chains);
   }
 
+  if (isa<UndefValue>(Init)) {
+    EVT VT = EVT::getEVT(InitTy);
+    PointerType *PtrTy = PointerType::get(InitTy, AMDGPUAS::PRIVATE_ADDRESS);
+    return DAG.getStore(Chain, DL, DAG.getUNDEF(VT), InitPtr,
+                        MachinePointerInfo(UndefValue::get(PtrTy)), false, false,
+                        TD->getPrefTypeAlignment(InitTy));
+  }
+
   Init->dump();
   llvm_unreachable("Unhandled constant initializer");
 }
@@ -694,11 +702,19 @@ SDValue AMDGPUTargetLowering::LowerGlobalAddress(AMDGPUMachineFunction* MFI,
     unsigned Size = TD->getTypeAllocSize(EltType);
     unsigned Alignment = TD->getPrefTypeAlignment(EltType);
 
+    MVT PrivPtrVT = getPointerTy(AMDGPUAS::PRIVATE_ADDRESS);
+    MVT ConstPtrVT = getPointerTy(AMDGPUAS::CONSTANT_ADDRESS);
+
+    int FI = FrameInfo->CreateStackObject(Size, Alignment, false);
+    SDValue InitPtr = DAG.getFrameIndex(FI, PrivPtrVT);
+
     const GlobalVariable *Var = cast<GlobalVariable>(GV);
+    if (!Var->hasInitializer()) {
+      // This has no use, but bugpoint will hit it.
+      return DAG.getZExtOrTrunc(InitPtr, SDLoc(Op), ConstPtrVT);
+    }
+
     const Constant *Init = Var->getInitializer();
-    int FI = FrameInfo->CreateStackObject(Size, Alignment, false);
-    SDValue InitPtr = DAG.getFrameIndex(FI,
-        getPointerTy(AMDGPUAS::PRIVATE_ADDRESS));
     SmallVector<SDNode*, 8> WorkList;
 
     for (SDNode::use_iterator I = DAG.getEntryNode()->use_begin(),
@@ -717,8 +733,7 @@ SDValue AMDGPUTargetLowering::LowerGlobalAddress(AMDGPUMachineFunction* MFI,
       }
       DAG.UpdateNodeOperands(*I, Ops);
     }
-    return DAG.getZExtOrTrunc(InitPtr, SDLoc(Op),
-        getPointerTy(AMDGPUAS::CONSTANT_ADDRESS));
+    return DAG.getZExtOrTrunc(InitPtr, SDLoc(Op), ConstPtrVT);
   }
   }
 }
diff --git a/llvm/test/CodeGen/R600/no-initializer-constant-addrspace.ll b/llvm/test/CodeGen/R600/no-initializer-constant-addrspace.ll
new file mode 100644
index 00000000000..ab82e7ee799
--- /dev/null
+++ b/llvm/test/CodeGen/R600/no-initializer-constant-addrspace.ll
@@ -0,0 +1,20 @@
+; RUN: llc -march=r600 -mcpu=SI -o /dev/null %s
+; RUN: llc -march=r600 -mcpu=cypress -o /dev/null %s
+
+@extern_const_addrspace = external unnamed_addr addrspace(2) constant [5 x i32], align 4
+
+; FUNC-LABEL: @load_extern_const_init
+define void @load_extern_const_init(i32 addrspace(1)* %out) nounwind {
+  %val = load i32 addrspace(2)* getelementptr ([5 x i32] addrspace(2)* @extern_const_addrspace, i64 0, i64 3), align 4
+  store i32 %val, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+@undef_const_addrspace = unnamed_addr addrspace(2) constant [5 x i32] undef, align 4
+
+; FUNC-LABEL: @load_undef_const_init
+define void @load_undef_const_init(i32 addrspace(1)* %out) nounwind {
+  %val = load i32 addrspace(2)* getelementptr ([5 x i32] addrspace(2)* @undef_const_addrspace, i64 0, i64 3), align 4
+  store i32 %val, i32 addrspace(1)* %out, align 4
+  ret void
+}