diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 629313c7120..66c1356152d 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -7801,6 +7801,24 @@ SDValue DAGCombiner::visitFADD(SDNode *N) { N0.getOperand(0), DAG.getConstantFP(4.0, DL, VT)); } } + + // Canonicalize chains of adds to LHS to simplify the following transform. + if (N0.getOpcode() != ISD::FADD && N1.getOpcode() == ISD::FADD) + return DAG.getNode(ISD::FADD, SDLoc(N), VT, N1, N0); + + // Convert a chain of 3 dependent operations into 2 independent operations + // and 1 dependent operation: + // (fadd N0: (fadd N00: (fadd z, w), N01: y), N1: x) -> + // (fadd N00: (fadd z, w), (fadd N1: x, N01: y)) + if (N0.getOpcode() == ISD::FADD && N0.hasOneUse() && + N1.getOpcode() != ISD::FADD) { + SDValue N00 = N0.getOperand(0); + if (N00.getOpcode() == ISD::FADD) { + SDValue N01 = N0.getOperand(1); + SDValue NewAdd = DAG.getNode(ISD::FADD, SDLoc(N), VT, N1, N01); + return DAG.getNode(ISD::FADD, SDLoc(N), VT, N00, NewAdd); + } + } } // enable-unsafe-fp-math // FADD -> FMA combines: |
