diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/utils/TableGen/DAGISelEmitter.cpp | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/llvm/utils/TableGen/DAGISelEmitter.cpp b/llvm/utils/TableGen/DAGISelEmitter.cpp index f0cebeddd3a..e1d09a89496 100644 --- a/llvm/utils/TableGen/DAGISelEmitter.cpp +++ b/llvm/utils/TableGen/DAGISelEmitter.cpp @@ -568,9 +568,12 @@ void PatternCodeEmitter::EmitMatchCode(TreePatternNode *N, TreePatternNode *P, // Check if it's profitable to fold the node. e.g. Check for multiple uses // of actual result? std::string ParentName(RootName.begin(), RootName.end()-1); - emitCheck("IsProfitableToFold(" + getValueName(RootName) + - ", " + getNodeName(ParentName) + ", N)"); - if (NodeHasChain) { + if (!NodeHasChain) { + // If this is just an interior node, check to see if it has a single + // use. If the node has multiple uses and the pattern has a load as + // an operand, then we can't fold the load. + emitCheck(getValueName(RootName) + ".hasOneUse()"); + } else { // If the immediate use can somehow reach this node through another // path, then can't fold it either or it will create a cycle. // e.g. In the following diagram, XX can reach ld through YY. If @@ -588,6 +591,8 @@ void PatternCodeEmitter::EmitMatchCode(TreePatternNode *N, TreePatternNode *P, // We know we need the check if N's parent is not the root. bool NeedCheck = P != Pattern; if (!NeedCheck) { + // If the parent is the root and the node has more than one operand, + // we need to check. const SDNodeInfo &PInfo = CGP.getSDNodeInfo(P->getOperator()); NeedCheck = P->getOperator() == CGP.get_intrinsic_void_sdnode() || @@ -600,8 +605,13 @@ void PatternCodeEmitter::EmitMatchCode(TreePatternNode *N, TreePatternNode *P, } if (NeedCheck) { + emitCheck("IsProfitableToFold(" + getValueName(RootName) + + ", " + getNodeName(ParentName) + ", N)"); emitCheck("IsLegalToFold(" + getValueName(RootName) + ", " + getNodeName(ParentName) + ", N)"); + } else { + // Otherwise, just verify that the node only has a single use. + emitCheck(getValueName(RootName) + ".hasOneUse()"); } } } |
