The previous fix of widening divides that trap was too fragile as it depends on custom

lowering and requires that certain types exist in ValueTypes.h.  Modified widening to
check if an op can trap and if so, the widening algorithm will apply only the op on
the defined elements.  It is safer to do this in widening because the optimizer can't
guarantee removing unused ops in some cases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95823 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 107 insertions, 3 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index bf95bb532f..e955e10619 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -1242,10 +1242,96 @@ void DAGTypeLegalizer::WidenVectorResult(SDNode *N, unsigned ResNo) {
 
 SDValue DAGTypeLegalizer::WidenVecRes_Binary(SDNode *N) {
   // Binary op widening.
+  unsigned Opcode = N->getOpcode();
+  DebugLoc dl = N->getDebugLoc();
   EVT WidenVT = TLI.getTypeToTransformTo(*DAG.getContext(), N->getValueType(0));
-  SDValue InOp1 = GetWidenedVector(N->getOperand(0));
-  SDValue InOp2 = GetWidenedVector(N->getOperand(1));
-  return DAG.getNode(N->getOpcode(), N->getDebugLoc(), WidenVT, InOp1, InOp2);
+  EVT WidenEltVT = WidenVT.getVectorElementType();
+  EVT VT = WidenVT;
+  unsigned NumElts =  VT.getVectorNumElements();
+  while (!TLI.isTypeLegal(VT) && NumElts != 1) {
+     NumElts = NumElts / 2;
+     VT = EVT::getVectorVT(*DAG.getContext(), WidenEltVT, NumElts);
+  }
+
+  if (NumElts != 1 && !TLI.canOpTrap(N->getOpcode(), VT)) {
+    // Operation doesn't trap so just widen as normal.
+    SDValue InOp1 = GetWidenedVector(N->getOperand(0));
+    SDValue InOp2 = GetWidenedVector(N->getOperand(1));
+    return DAG.getNode(N->getOpcode(), dl, WidenVT, InOp1, InOp2);
+  } else if (NumElts == 1) {
+    // No legal vector version so unroll the vector operation and then widen.
+    return DAG.UnrollVectorOp(N, WidenVT.getVectorNumElements());
+  } else {
+    // Since the operation can trap, apply operation on the original vector.
+    SDValue InOp1 = GetWidenedVector(N->getOperand(0));
+    SDValue InOp2 = GetWidenedVector(N->getOperand(1));
+    unsigned CurNumElts = N->getValueType(0).getVectorNumElements();
+
+    SmallVector<SDValue, 16> ConcatOps(CurNumElts);
+    unsigned ConcatEnd = 0;  // Current ConcatOps index.
+    unsigned Idx = 0;        // Current Idx into input vectors.
+    while (CurNumElts != 0) {
+      while (CurNumElts >= NumElts) {
+        SDValue EOp1 = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, VT, InOp1,
+                                   DAG.getIntPtrConstant(Idx));
+        SDValue EOp2 = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, VT, InOp2,
+                                   DAG.getIntPtrConstant(Idx));
+        ConcatOps[ConcatEnd++] = DAG.getNode(Opcode, dl, VT, EOp1, EOp2);
+        Idx += NumElts;
+        CurNumElts -= NumElts;
+      }
+      EVT PrevVecVT = VT;
+      do {
+        NumElts = NumElts / 2;
+        VT = EVT::getVectorVT(*DAG.getContext(), WidenEltVT, NumElts);
+      } while (!TLI.isTypeLegal(VT) && NumElts != 1);
+
+      if (NumElts == 1) {
+        // Since we are using concat vector, build a vector from the scalar ops.
+        SDValue VecOp = DAG.getUNDEF(PrevVecVT);
+        for (unsigned i = 0; i != CurNumElts; ++i, ++Idx) {
+          SDValue EOp1 = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, WidenEltVT, 
+                                     InOp1, DAG.getIntPtrConstant(Idx));
+          SDValue EOp2 = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, WidenEltVT, 
+                                     InOp2, DAG.getIntPtrConstant(Idx));
+          VecOp = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, PrevVecVT, VecOp,
+                              DAG.getNode(Opcode, dl, WidenEltVT, EOp1, EOp2),
+                              DAG.getIntPtrConstant(i));
+        }
+        CurNumElts = 0;
+        ConcatOps[ConcatEnd++] = VecOp;
+      }
+    }
+
+    // Check to see if we have a single operation with the widen type.
+    if (ConcatEnd == 1) {
+      VT = ConcatOps[0].getValueType();
+      if (VT == WidenVT)
+        return ConcatOps[0];
+    }
+
+    // Rebuild vector to one with the widen type
+    Idx = ConcatEnd - 1;
+    while (Idx != 0) {
+      VT = ConcatOps[Idx--].getValueType();
+      while (Idx != 0 && ConcatOps[Idx].getValueType() == VT)
+        --Idx;
+      if (Idx != 0) {
+        VT = ConcatOps[Idx].getValueType();
+        ConcatOps[Idx+1] = DAG.getNode(ISD::CONCAT_VECTORS, dl, VT,
+                                     &ConcatOps[Idx+1], ConcatEnd - Idx - 1);
+        ConcatEnd = Idx + 2;
+      }
+    }
+    
+    unsigned NumOps = WidenVT.getVectorNumElements()/VT.getVectorNumElements();
+    if (NumOps != ConcatEnd ) {
+      SDValue UndefVal = DAG.getUNDEF(VT);
+      for (unsigned j = ConcatEnd; j < NumOps; ++j)
+        ConcatOps[j] = UndefVal;
+    }
+    return DAG.getNode(ISD::CONCAT_VECTORS, dl, WidenVT, &ConcatOps[0], NumOps);
+  }
 }
 
 SDValue DAGTypeLegalizer::WidenVecRes_Convert(SDNode *N) {
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index d74ec7e2e5..1683d01bba 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -540,6 +540,24 @@ TargetLowering::~TargetLowering() {
   delete &TLOF;
 }
 
+/// canOpTrap - Returns true if the operation can trap for the value type.
+/// VT must be a legal type.
+bool TargetLowering::canOpTrap(unsigned Op, EVT VT) const {
+  assert(isTypeLegal(VT));
+  switch (Op) {
+  default:
+    return false;
+  case ISD::FDIV:
+  case ISD::FREM:
+  case ISD::SDIV:
+  case ISD::UDIV:
+  case ISD::SREM:
+  case ISD::UREM:
+    return true;
+  }
+}
+
+
 static unsigned getVectorTypeBreakdownMVT(MVT VT, MVT &IntermediateVT,
                                        unsigned &NumIntermediates,
                                        EVT &RegisterVT,