diff options
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 957aa7bf90b..31f0df99d47 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -8477,7 +8477,9 @@ SDValue DAGCombiner::visitFMA(SDNode *N) { // FDIVs may be lower than the cost of one FDIV and two FMULs. Another reason // is the critical path is increased from "one FDIV" to "one FDIV + one FMUL". SDValue DAGCombiner::combineRepeatedFPDivisors(SDNode *N) { - if (!DAG.getTarget().Options.UnsafeFPMath) + bool UnsafeMath = DAG.getTarget().Options.UnsafeFPMath; + const SDNodeFlags *Flags = N->getFlags(); + if (!UnsafeMath && !Flags->hasAllowReciprocal()) return SDValue(); // Skip if current node is a reciprocal. @@ -8496,9 +8498,14 @@ SDValue DAGCombiner::combineRepeatedFPDivisors(SDNode *N) { // Find all FDIV users of the same divisor. // Use a set because duplicates may be present in the user list. SetVector<SDNode *> Users; - for (auto *U : N1->uses()) - if (U->getOpcode() == ISD::FDIV && U->getOperand(1) == N1) - Users.insert(U); + for (auto *U : N1->uses()) { + if (U->getOpcode() == ISD::FDIV && U->getOperand(1) == N1) { + // This division is eligible for optimization only if global unsafe math + // is enabled or if this division allows reciprocal formation. + if (UnsafeMath || U->getFlags()->hasAllowReciprocal()) + Users.insert(U); + } + } // Now that we have the actual number of divisor uses, make sure it meets // the minimum threshold specified by the target. @@ -8508,7 +8515,6 @@ SDValue DAGCombiner::combineRepeatedFPDivisors(SDNode *N) { EVT VT = N->getValueType(0); SDLoc DL(N); SDValue FPOne = DAG.getConstantFP(1.0, DL, VT); - const SDNodeFlags *Flags = &cast<BinaryWithFlagsSDNode>(N)->Flags; SDValue Reciprocal = DAG.getNode(ISD::FDIV, DL, VT, FPOne, N1, Flags); // Dividend / Divisor -> Dividend * Reciprocal |
