diff options
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 4b1945efe4..81058152eb 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -967,6 +967,13 @@ SDValue DAGCombiner::visitADD(SDNode *N) { // fold (add x, 0) -> x if (N1C && N1C->isNullValue()) return N0; + // fold (add Sym, c) -> Sym+c + if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0)) + if (!AfterLegalize && TLI.isOffsetFoldingLegal(GA) && N1C && + GA->getOpcode() == ISD::GlobalAddress) + return DAG.getGlobalAddress(GA->getGlobal(), VT, + GA->getOffset() + + (uint64_t)N1C->getSExtValue()); // fold ((c1-A)+c2) -> (c1+c2)-A if (N1C && N0.getOpcode() == ISD::SUB) if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0))) @@ -1133,6 +1140,21 @@ SDValue DAGCombiner::visitSUB(SDNode *N) { if (N1.getOpcode() == ISD::UNDEF) return N1; + // If the relocation model supports it, consider symbol offsets. + if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0)) + if (!AfterLegalize && TLI.isOffsetFoldingLegal(GA)) { + // fold (sub Sym, c) -> Sym-c + if (N1C && GA->getOpcode() == ISD::GlobalAddress) + return DAG.getGlobalAddress(GA->getGlobal(), VT, + GA->getOffset() - + (uint64_t)N1C->getSExtValue()); + // fold (sub Sym+c1, Sym+c2) -> c1-c2 + if (GlobalAddressSDNode *GB = dyn_cast<GlobalAddressSDNode>(N1)) + if (GA->getGlobal() == GB->getGlobal()) + return DAG.getConstant((uint64_t)GA->getOffset() - GB->getOffset(), + VT); + } + return SDValue(); } |