diff options
author | Nate Begeman <natebegeman@mac.com> | 2005-04-12 23:12:17 +0000 |
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committer | Nate Begeman <natebegeman@mac.com> | 2005-04-12 23:12:17 +0000 |
commit | b882752bd04602249d391699dc7183de007f8964 (patch) | |
tree | cb91088cbb4b4e3a16be13e9663b584184a03d2d /lib/CodeGen | |
parent | 9765c25eb775e223612cd996d78a5a141360dabf (diff) |
Fold shift by size larger than type size to undef
Make llvm undef values generate ISD::UNDEF nodes
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21261 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen')
-rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 15 | ||||
-rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 9 |
2 files changed, 5 insertions, 19 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 634197c0f96..613d0983ad6 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -755,19 +755,12 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, case ISD::SHL: case ISD::SRL: - // If the shift amount is bigger than the size of the data, simplify. + case ISD::SRA: + // If the shift amount is bigger than the size of the data, then all the + // bits are shifted out. Simplify to loading constant zero. if (C2 >= MVT::getSizeInBits(N1.getValueType())) { - if (TLI.getShiftAmountFlavor() == TargetLowering::Mask) { - unsigned NewAmt = - C2 & ((1 << MVT::getSizeInBits(N1.getValueType()))-1); - return getNode(Opcode, VT, N1, getConstant(NewAmt,N2.getValueType())); - } else if (TLI.getShiftAmountFlavor() == TargetLowering::Extend) { - // Shifting all of the bits out? - return getConstant(0, N1.getValueType()); - } + return getNode(ISD::UNDEF, N1.getValueType()); } - // FALL THROUGH. - case ISD::SRA: if (C2 == 0) return N1; break; diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index bfceecb7aaf..f041905bb32 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -266,14 +266,7 @@ public: } else if (isa<ConstantPointerNull>(C)) { return N = DAG.getConstant(0, TLI.getPointerTy()); } else if (isa<UndefValue>(C)) { - /// FIXME: Implement UNDEFVALUE better. - if (MVT::isInteger(VT)) - return N = DAG.getConstant(0, VT); - else if (MVT::isFloatingPoint(VT)) - return N = DAG.getConstantFP(0, VT); - else - assert(0 && "Unknown value type!"); - + return N = DAG.getNode(ISD::UNDEF, VT); } else if (ConstantFP *CFP = dyn_cast<ConstantFP>(C)) { return N = DAG.getConstantFP(CFP->getValue(), VT); } else { |