diff options
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index ded4f04c57a..1c44a5d5ce3 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -9895,10 +9895,11 @@ SDValue DAGCombiner::visitZERO_EXTEND_VECTOR_INREG(SDNode *N) { SDValue DAGCombiner::visitTRUNCATE(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); + EVT SrcVT = N0.getValueType(); bool isLE = DAG.getDataLayout().isLittleEndian(); // noop truncate - if (N0.getValueType() == N->getValueType(0)) + if (SrcVT == VT) return N0; // fold (truncate (truncate x)) -> (truncate x) @@ -9999,6 +10000,19 @@ SDValue DAGCombiner::visitTRUNCATE(SDNode *N) { } } + // Attempt to pre-truncate BUILD_VECTOR sources. + if (N0.getOpcode() == ISD::BUILD_VECTOR && !LegalOperations && + TLI.isTruncateFree(SrcVT.getScalarType(), VT.getScalarType())) { + SDLoc DL(N); + EVT SVT = VT.getScalarType(); + SmallVector<SDValue, 8> TruncOps; + for (const SDValue &Op : N0->op_values()) { + SDValue TruncOp = DAG.getNode(ISD::TRUNCATE, DL, SVT, Op); + TruncOps.push_back(TruncOp); + } + return DAG.getBuildVector(VT, DL, TruncOps); + } + // Fold a series of buildvector, bitcast, and truncate if possible. // For example fold // (2xi32 trunc (bitcast ((4xi32)buildvector x, x, y, y) 2xi64)) to |
