It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp
new file mode 100644
index 0000000..48f7b30
--- /dev/null
+++ b/lib/Analysis/PostDominators.cpp
@@ -0,0 +1,262 @@
+//===- PostDominators.cpp - Post-Dominator Calculation --------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the post-dominator construction algorithms.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/PostDominators.h"
+#include "llvm/Instructions.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/SetOperations.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// PostDominatorTree Implementation
+//===----------------------------------------------------------------------===//
+
+char PostDominatorTree::ID = 0;
+char PostDominanceFrontier::ID = 0;
+static RegisterPass<PostDominatorTree>
+F("postdomtree", "Post-Dominator Tree Construction", true);
+
+unsigned PostDominatorTree::DFSPass(BasicBlock *V, InfoRec &VInfo,
+ unsigned N) {
+ std::vector<std::pair<BasicBlock *, InfoRec *> > workStack;
+ std::set<BasicBlock *> visited;
+ workStack.push_back(std::make_pair(V, &VInfo));
+
+ do {
+ BasicBlock *currentBB = workStack.back().first;
+ InfoRec *currentVInfo = workStack.back().second;
+
+ // Visit each block only once.
+ if (visited.count(currentBB) == 0) {
+
+ visited.insert(currentBB);
+ currentVInfo->Semi = ++N;
+ currentVInfo->Label = currentBB;
+
+ Vertex.push_back(currentBB); // Vertex[n] = current;
+ // Info[currentBB].Ancestor = 0;
+ // Ancestor[n] = 0
+ // Child[currentBB] = 0;
+ currentVInfo->Size = 1; // Size[currentBB] = 1
+ }
+
+ // Visit children
+ bool visitChild = false;
+ for (pred_iterator PI = pred_begin(currentBB), PE = pred_end(currentBB);
+ PI != PE && !visitChild; ++PI) {
+ InfoRec &SuccVInfo = Info[*PI];
+ if (SuccVInfo.Semi == 0) {
+ SuccVInfo.Parent = currentBB;
+ if (visited.count (*PI) == 0) {
+ workStack.push_back(std::make_pair(*PI, &SuccVInfo));
+ visitChild = true;
+ }
+ }
+ }
+
+ // If all children are visited or if this block has no child then pop this
+ // block out of workStack.
+ if (!visitChild)
+ workStack.pop_back();
+
+ } while (!workStack.empty());
+
+ return N;
+}
+
+void PostDominatorTree::Compress(BasicBlock *V, InfoRec &VInfo) {
+ BasicBlock *VAncestor = VInfo.Ancestor;
+ InfoRec &VAInfo = Info[VAncestor];
+ if (VAInfo.Ancestor == 0)
+ return;
+
+ Compress(VAncestor, VAInfo);
+
+ BasicBlock *VAncestorLabel = VAInfo.Label;
+ BasicBlock *VLabel = VInfo.Label;
+ if (Info[VAncestorLabel].Semi < Info[VLabel].Semi)
+ VInfo.Label = VAncestorLabel;
+
+ VInfo.Ancestor = VAInfo.Ancestor;
+}
+
+BasicBlock *PostDominatorTree::Eval(BasicBlock *V) {
+ InfoRec &VInfo = Info[V];
+
+ // Higher-complexity but faster implementation
+ if (VInfo.Ancestor == 0)
+ return V;
+ Compress(V, VInfo);
+ return VInfo.Label;
+}
+
+void PostDominatorTree::Link(BasicBlock *V, BasicBlock *W,
+ InfoRec &WInfo) {
+ // Higher-complexity but faster implementation
+ WInfo.Ancestor = V;
+}
+
+void PostDominatorTree::calculate(Function &F) {
+ // Step #0: Scan the function looking for the root nodes of the post-dominance
+ // relationships. These blocks, which have no successors, end with return and
+ // unwind instructions.
+ for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
+ if (succ_begin(I) == succ_end(I))
+ Roots.push_back(I);
+
+ Vertex.push_back(0);
+
+ // Step #1: Number blocks in depth-first order and initialize variables used
+ // in later stages of the algorithm.
+ unsigned N = 0;
+ for (unsigned i = 0, e = Roots.size(); i != e; ++i)
+ N = DFSPass(Roots[i], Info[Roots[i]], N);
+
+ for (unsigned i = N; i >= 2; --i) {
+ BasicBlock *W = Vertex[i];
+ InfoRec &WInfo = Info[W];
+
+ // Step #2: Calculate the semidominators of all vertices
+ for (succ_iterator SI = succ_begin(W), SE = succ_end(W); SI != SE; ++SI)
+ if (Info.count(*SI)) { // Only if this predecessor is reachable!
+ unsigned SemiU = Info[Eval(*SI)].Semi;
+ if (SemiU < WInfo.Semi)
+ WInfo.Semi = SemiU;
+ }
+
+ Info[Vertex[WInfo.Semi]].Bucket.push_back(W);
+
+ BasicBlock *WParent = WInfo.Parent;
+ Link(WParent, W, WInfo);
+
+ // Step #3: Implicitly define the immediate dominator of vertices
+ std::vector<BasicBlock*> &WParentBucket = Info[WParent].Bucket;
+ while (!WParentBucket.empty()) {
+ BasicBlock *V = WParentBucket.back();
+ WParentBucket.pop_back();
+ BasicBlock *U = Eval(V);
+ IDoms[V] = Info[U].Semi < Info[V].Semi ? U : WParent;
+ }
+ }
+
+ // Step #4: Explicitly define the immediate dominator of each vertex
+ for (unsigned i = 2; i <= N; ++i) {
+ BasicBlock *W = Vertex[i];
+ BasicBlock *&WIDom = IDoms[W];
+ if (WIDom != Vertex[Info[W].Semi])
+ WIDom = IDoms[WIDom];
+ }
+
+ if (Roots.empty()) return;
+
+ // Add a node for the root. This node might be the actual root, if there is
+ // one exit block, or it may be the virtual exit (denoted by (BasicBlock *)0)
+ // which postdominates all real exits if there are multiple exit blocks.
+ BasicBlock *Root = Roots.size() == 1 ? Roots[0] : 0;
+ DomTreeNodes[Root] = RootNode = new DomTreeNode(Root, 0);
+
+ // Loop over all of the reachable blocks in the function...
+ for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
+ if (BasicBlock *ImmPostDom = getIDom(I)) { // Reachable block.
+ DomTreeNode *&BBNode = DomTreeNodes[I];
+ if (!BBNode) { // Haven't calculated this node yet?
+ // Get or calculate the node for the immediate dominator
+ DomTreeNode *IPDomNode = getNodeForBlock(ImmPostDom);
+
+ // Add a new tree node for this BasicBlock, and link it as a child of
+ // IDomNode
+ DomTreeNode *C = new DomTreeNode(I, IPDomNode);
+ DomTreeNodes[I] = C;
+ BBNode = IPDomNode->addChild(C);
+ }
+ }
+
+ // Free temporary memory used to construct idom's
+ IDoms.clear();
+ Info.clear();
+ std::vector<BasicBlock*>().swap(Vertex);
+
+ int dfsnum = 0;
+ // Iterate over all nodes in depth first order...
+ for (unsigned i = 0, e = Roots.size(); i != e; ++i)
+ for (idf_iterator<BasicBlock*> I = idf_begin(Roots[i]),
+ E = idf_end(Roots[i]); I != E; ++I) {
+ if (!getNodeForBlock(*I)->getIDom())
+ getNodeForBlock(*I)->assignDFSNumber(dfsnum);
+ }
+ DFSInfoValid = true;
+}
+
+
+DomTreeNode *PostDominatorTree::getNodeForBlock(BasicBlock *BB) {
+ DomTreeNode *&BBNode = DomTreeNodes[BB];
+ if (BBNode) return BBNode;
+
+ // Haven't calculated this node yet? Get or calculate the node for the
+ // immediate postdominator.
+ BasicBlock *IPDom = getIDom(BB);
+ DomTreeNode *IPDomNode = getNodeForBlock(IPDom);
+
+ // Add a new tree node for this BasicBlock, and link it as a child of
+ // IDomNode
+ DomTreeNode *C = new DomTreeNode(BB, IPDomNode);
+ DomTreeNodes[BB] = C;
+ return BBNode = IPDomNode->addChild(C);
+}
+
+//===----------------------------------------------------------------------===//
+// PostDominanceFrontier Implementation
+//===----------------------------------------------------------------------===//
+
+static RegisterPass<PostDominanceFrontier>
+H("postdomfrontier", "Post-Dominance Frontier Construction", true);
+
+const DominanceFrontier::DomSetType &
+PostDominanceFrontier::calculate(const PostDominatorTree &DT,
+ const DomTreeNode *Node) {
+ // Loop over CFG successors to calculate DFlocal[Node]
+ BasicBlock *BB = Node->getBlock();
+ DomSetType &S = Frontiers[BB]; // The new set to fill in...
+ if (getRoots().empty()) return S;
+
+ if (BB)
+ for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB);
+ SI != SE; ++SI) {
+ // Does Node immediately dominate this predecessor?
+ DomTreeNode *SINode = DT[*SI];
+ if (SINode && SINode->getIDom() != Node)
+ S.insert(*SI);
+ }
+
+ // At this point, S is DFlocal. Now we union in DFup's of our children...
+ // Loop through and visit the nodes that Node immediately dominates (Node's
+ // children in the IDomTree)
+ //
+ for (DomTreeNode::const_iterator
+ NI = Node->begin(), NE = Node->end(); NI != NE; ++NI) {
+ DomTreeNode *IDominee = *NI;
+ const DomSetType &ChildDF = calculate(DT, IDominee);
+
+ DomSetType::const_iterator CDFI = ChildDF.begin(), CDFE = ChildDF.end();
+ for (; CDFI != CDFE; ++CDFI) {
+ if (!DT.properlyDominates(Node, DT[*CDFI]))
+ S.insert(*CDFI);
+ }
+ }
+
+ return S;
+}
+
+// Ensure that this .cpp file gets linked when PostDominators.h is used.
+DEFINING_FILE_FOR(PostDominanceFrontier)