Make codegen able to handle values of empty types. This is one way

to fix PR9900. I will keep it open until sable is able to comment on it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131294 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 33 insertions, 6 deletions

diff --git a/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp b/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
index a1e8254189..2cb16f589a 100644
--- a/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
+++ b/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
@@ -155,6 +155,10 @@ void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf) {
          const PHINode *PN = dyn_cast<PHINode>(I); ++I) {
       if (PN->use_empty()) continue;
 
+      // Skip empty types
+      if (PN->getType()->isEmptyTy())
+        continue;
+
       DebugLoc DL = PN->getDebugLoc();
       unsigned PHIReg = ValueMap[PN];
       assert(PHIReg && "PHI node does not have an assigned virtual register!");
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 73a44e9e1a..72a46c99c0 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1175,6 +1175,10 @@ void SelectionDAGBuilder::visitRet(const ReturnInst &I) {
 /// created for it, emit nodes to copy the value into the virtual
 /// registers.
 void SelectionDAGBuilder::CopyToExportRegsIfNeeded(const Value *V) {
+  // Skip empty types
+  if (V->getType()->isEmptyTy())
+    return;
+
   DenseMap<const Value *, unsigned>::iterator VMI = FuncInfo.ValueMap.find(V);
   if (VMI != FuncInfo.ValueMap.end()) {
     assert(!V->use_empty() && "Unused value assigned virtual registers!");
@@ -2810,16 +2814,18 @@ void SelectionDAGBuilder::visitInsertValue(const InsertValueInst &I) {
   SmallVector<SDValue, 4> Values(NumAggValues);
 
   SDValue Agg = getValue(Op0);
-  SDValue Val = getValue(Op1);
   unsigned i = 0;
   // Copy the beginning value(s) from the original aggregate.
   for (; i != LinearIndex; ++i)
     Values[i] = IntoUndef ? DAG.getUNDEF(AggValueVTs[i]) :
                 SDValue(Agg.getNode(), Agg.getResNo() + i);
   // Copy values from the inserted value(s).
-  for (; i != LinearIndex + NumValValues; ++i)
-    Values[i] = FromUndef ? DAG.getUNDEF(AggValueVTs[i]) :
-                SDValue(Val.getNode(), Val.getResNo() + i - LinearIndex);
+  if (NumValValues) {
+    SDValue Val = getValue(Op1);
+    for (; i != LinearIndex + NumValValues; ++i)
+      Values[i] = FromUndef ? DAG.getUNDEF(AggValueVTs[i]) :
+                  SDValue(Val.getNode(), Val.getResNo() + i - LinearIndex);
+  }
   // Copy remaining value(s) from the original aggregate.
   for (; i != NumAggValues; ++i)
     Values[i] = IntoUndef ? DAG.getUNDEF(AggValueVTs[i]) :
@@ -2842,6 +2848,13 @@ void SelectionDAGBuilder::visitExtractValue(const ExtractValueInst &I) {
   ComputeValueVTs(TLI, ValTy, ValValueVTs);
 
   unsigned NumValValues = ValValueVTs.size();
+
+  // Ignore a extractvalue that produces an empty object
+  if (!NumValValues) {
+    setValue(&I, DAG.getUNDEF(MVT(MVT::Other)));
+    return;
+  }
+
   SmallVector<SDValue, 4> Values(NumValValues);
 
   SDValue Agg = getValue(Op0);
@@ -4827,8 +4840,14 @@ void SelectionDAGBuilder::LowerCallTo(ImmutableCallSite CS, SDValue Callee,
 
   for (ImmutableCallSite::arg_iterator i = CS.arg_begin(), e = CS.arg_end();
        i != e; ++i) {
-    SDValue ArgNode = getValue(*i);
-    Entry.Node = ArgNode; Entry.Ty = (*i)->getType();
+    const Value *V = *i;
+
+    // Skip empty types
+    if (V->getType()->isEmptyTy())
+      continue;
+
+    SDValue ArgNode = getValue(V);
+    Entry.Node = ArgNode; Entry.Ty = V->getType();
 
     unsigned attrInd = i - CS.arg_begin() + 1;
     Entry.isSExt  = CS.paramHasAttr(attrInd, Attribute::SExt);
@@ -6498,6 +6517,10 @@ SelectionDAGBuilder::HandlePHINodesInSuccessorBlocks(const BasicBlock *LLVMBB) {
       // Ignore dead phi's.
       if (PN->use_empty()) continue;
 
+      // Skip empty types
+      if (PN->getType()->isEmptyTy())
+        continue;
+
       unsigned Reg;
       const Value *PHIOp = PN->getIncomingValueForBlock(LLVMBB);