+/// CombineChildVariants - Given a bunch of permutations of each child of the
+/// 'operator' node, put them together in all possible ways.
+static void CombineChildVariants(TreePatternNode *Orig,
+ const std::vector<std::vector<TreePatternNode*> > &ChildVariants,
+ std::vector<TreePatternNode*> &OutVariants,
+ DAGISelEmitter &ISE) {
+ // Make sure that each operand has at least one variant to choose from.
+ for (unsigned i = 0, e = ChildVariants.size(); i != e; ++i)
+ if (ChildVariants[i].empty())
+ return;
+
+ // The end result is an all-pairs construction of the resultant pattern.
+ std::vector<unsigned> Idxs;
+ Idxs.resize(ChildVariants.size());
+ bool NotDone = true;
+ while (NotDone) {
+ // Create the variant and add it to the output list.
+ std::vector<TreePatternNode*> NewChildren;
+ for (unsigned i = 0, e = ChildVariants.size(); i != e; ++i)
+ NewChildren.push_back(ChildVariants[i][Idxs[i]]);
+ TreePatternNode *R = new TreePatternNode(Orig->getOperator(), NewChildren);
+
+ // Copy over properties.
+ R->setName(Orig->getName());
+ R->setPredicateFn(Orig->getPredicateFn());
+ R->setTransformFn(Orig->getTransformFn());
+ R->setType(Orig->getExtType());
+
+ // If this pattern cannot every match, do not include it as a variant.
+ std::string ErrString;
+ if (!R->canPatternMatch(ErrString, ISE)) {
+ delete R;
+ } else {
+ bool AlreadyExists = false;
+
+ // Scan to see if this pattern has already been emitted. We can get
+ // duplication due to things like commuting:
+ // (and GPRC:$a, GPRC:$b) -> (and GPRC:$b, GPRC:$a)
+ // which are the same pattern. Ignore the dups.
+ for (unsigned i = 0, e = OutVariants.size(); i != e; ++i)
+ if (R->isIsomorphicTo(OutVariants[i])) {
+ AlreadyExists = true;
+ break;
+ }
+
+ if (AlreadyExists)
+ delete R;
+ else
+ OutVariants.push_back(R);
+ }
+
+ // Increment indices to the next permutation.
+ NotDone = false;
+ // Look for something we can increment without causing a wrap-around.
+ for (unsigned IdxsIdx = 0; IdxsIdx != Idxs.size(); ++IdxsIdx) {
+ if (++Idxs[IdxsIdx] < ChildVariants[IdxsIdx].size()) {
+ NotDone = true; // Found something to increment.
+ break;
+ }
+ Idxs[IdxsIdx] = 0;
+ }
+ }
+}
+
+/// CombineChildVariants - A helper function for binary operators.
+///
+static void CombineChildVariants(TreePatternNode *Orig,
+ const std::vector<TreePatternNode*> &LHS,
+ const std::vector<TreePatternNode*> &RHS,
+ std::vector<TreePatternNode*> &OutVariants,
+ DAGISelEmitter &ISE) {
+ std::vector<std::vector<TreePatternNode*> > ChildVariants;
+ ChildVariants.push_back(LHS);
+ ChildVariants.push_back(RHS);
+ CombineChildVariants(Orig, ChildVariants, OutVariants, ISE);
+}
+
+
+static void GatherChildrenOfAssociativeOpcode(TreePatternNode *N,
+ std::vector<TreePatternNode *> &Children) {
+ assert(N->getNumChildren()==2 &&"Associative but doesn't have 2 children!");
+ Record *Operator = N->getOperator();
+
+ // Only permit raw nodes.
+ if (!N->getName().empty() || !N->getPredicateFn().empty() ||
+ N->getTransformFn()) {
+ Children.push_back(N);
+ return;
+ }
+
+ if (N->getChild(0)->isLeaf() || N->getChild(0)->getOperator() != Operator)
+ Children.push_back(N->getChild(0));
+ else
+ GatherChildrenOfAssociativeOpcode(N->getChild(0), Children);
+
+ if (N->getChild(1)->isLeaf() || N->getChild(1)->getOperator() != Operator)
+ Children.push_back(N->getChild(1));
+ else
+ GatherChildrenOfAssociativeOpcode(N->getChild(1), Children);
+}
+
+/// GenerateVariantsOf - Given a pattern N, generate all permutations we can of
+/// the (potentially recursive) pattern by using algebraic laws.
+///
+static void GenerateVariantsOf(TreePatternNode *N,
+ std::vector<TreePatternNode*> &OutVariants,
+ DAGISelEmitter &ISE) {
+ // We cannot permute leaves.
+ if (N->isLeaf()) {
+ OutVariants.push_back(N);
+ return;
+ }
+
+ // Look up interesting info about the node.
+ const SDNodeInfo &NodeInfo = ISE.getSDNodeInfo(N->getOperator());
+
+ // If this node is associative, reassociate.
+ if (NodeInfo.hasProperty(SDNodeInfo::SDNPAssociative)) {
+ // Reassociate by pulling together all of the linked operators
+ std::vector<TreePatternNode*> MaximalChildren;
+ GatherChildrenOfAssociativeOpcode(N, MaximalChildren);
+
+ // Only handle child sizes of 3. Otherwise we'll end up trying too many
+ // permutations.
+ if (MaximalChildren.size() == 3) {
+ // Find the variants of all of our maximal children.
+ std::vector<TreePatternNode*> AVariants, BVariants, CVariants;
+ GenerateVariantsOf(MaximalChildren[0], AVariants, ISE);
+ GenerateVariantsOf(MaximalChildren[1], BVariants, ISE);
+ GenerateVariantsOf(MaximalChildren[2], CVariants, ISE);
+
+ // There are only two ways we can permute the tree:
+ // (A op B) op C and A op (B op C)
+ // Within these forms, we can also permute A/B/C.
+
+ // Generate legal pair permutations of A/B/C.
+ std::vector<TreePatternNode*> ABVariants;
+ std::vector<TreePatternNode*> BAVariants;
+ std::vector<TreePatternNode*> ACVariants;
+ std::vector<TreePatternNode*> CAVariants;
+ std::vector<TreePatternNode*> BCVariants;
+ std::vector<TreePatternNode*> CBVariants;
+ CombineChildVariants(N, AVariants, BVariants, ABVariants, ISE);
+ CombineChildVariants(N, BVariants, AVariants, BAVariants, ISE);
+ CombineChildVariants(N, AVariants, CVariants, ACVariants, ISE);
+ CombineChildVariants(N, CVariants, AVariants, CAVariants, ISE);
+ CombineChildVariants(N, BVariants, CVariants, BCVariants, ISE);
+ CombineChildVariants(N, CVariants, BVariants, CBVariants, ISE);
+
+ // Combine those into the result: (x op x) op x
+ CombineChildVariants(N, ABVariants, CVariants, OutVariants, ISE);
+ CombineChildVariants(N, BAVariants, CVariants, OutVariants, ISE);
+ CombineChildVariants(N, ACVariants, BVariants, OutVariants, ISE);
+ CombineChildVariants(N, CAVariants, BVariants, OutVariants, ISE);
+ CombineChildVariants(N, BCVariants, AVariants, OutVariants, ISE);
+ CombineChildVariants(N, CBVariants, AVariants, OutVariants, ISE);
+
+ // Combine those into the result: x op (x op x)
+ CombineChildVariants(N, CVariants, ABVariants, OutVariants, ISE);
+ CombineChildVariants(N, CVariants, BAVariants, OutVariants, ISE);
+ CombineChildVariants(N, BVariants, ACVariants, OutVariants, ISE);
+ CombineChildVariants(N, BVariants, CAVariants, OutVariants, ISE);
+ CombineChildVariants(N, AVariants, BCVariants, OutVariants, ISE);
+ CombineChildVariants(N, AVariants, CBVariants, OutVariants, ISE);
+ return;
+ }
+ }
+
+ // Compute permutations of all children.
+ std::vector<std::vector<TreePatternNode*> > ChildVariants;
+ ChildVariants.resize(N->getNumChildren());
+ for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i)
+ GenerateVariantsOf(N->getChild(i), ChildVariants[i], ISE);
+
+ // Build all permutations based on how the children were formed.
+ CombineChildVariants(N, ChildVariants, OutVariants, ISE);
+
+ // If this node is commutative, consider the commuted order.
+ if (NodeInfo.hasProperty(SDNodeInfo::SDNPCommutative)) {
+ assert(N->getNumChildren()==2 &&"Commutative but doesn't have 2 children!");
+ // Consider the commuted order.
+ CombineChildVariants(N, ChildVariants[1], ChildVariants[0],
+ OutVariants, ISE);
+ }