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Fix PR681 by using the standard Lengauer and Tarjan algorithm for dominator

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set construction, rather than intersecting various std::sets.  This reduces
the memory usage for the testcase in PR681 from 496 to 26MB of ram on my
darwin system, and reduces the runtime from 32.8 to 0.8 seconds on a
2.5GHz G5.  This also enables future code sharing between Dom and PostDom
now that they share near-identical implementations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26707 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nate Begeman
2006-03-11 02:20:46 +00:00
parent 78167faa18
commit 442b32b5c5
2 changed files with 238 additions and 172 deletions
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81
include/llvm/Analysis/PostDominators.h
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@@ -18,6 +18,42 @@
namespace llvm {
//===-------------------------------------
/// ImmediatePostDominators Class - Concrete subclass of ImmediateDominatorsBase
/// that is used to compute a normal immediate dominator set.
///
struct ImmediatePostDominators : public ImmediateDominatorsBase {
ImmediatePostDominators() : ImmediateDominatorsBase(false) {}
virtual bool runOnFunction(Function &F);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
private:
struct InfoRec {
unsigned Semi;
unsigned Size;
BasicBlock *Label, *Parent, *Child, *Ancestor;
std::vector<BasicBlock*> Bucket;
InfoRec() : Semi(0), Size(0), Label(0), Parent(0), Child(0), Ancestor(0){}
};
// Vertex - Map the DFS number to the BasicBlock*
std::vector<BasicBlock*> Vertex;
// Info - Collection of information used during the computation of idoms.
std::map<BasicBlock*, InfoRec> Info;
unsigned DFSPass(BasicBlock *V, InfoRec &VInfo, unsigned N);
void Compress(BasicBlock *V, InfoRec &VInfo);
BasicBlock *Eval(BasicBlock *v);
void Link(BasicBlock *V, BasicBlock *W, InfoRec &WInfo);
};
/// PostDominatorSet Class - Concrete subclass of DominatorSetBase that is used
/// to compute the post-dominator set. Because there can be multiple exit nodes
/// in an LLVM function, we calculate post dominators with a special null block
@@ -27,40 +63,20 @@ namespace llvm {
///
struct PostDominatorSet : public DominatorSetBase {
PostDominatorSet() : DominatorSetBase(true) {}
virtual bool runOnFunction(Function &F);
/// getAnalysisUsage - This pass does not modify the function at all.
/// getAnalysisUsage - This simply provides a dominator set
///
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<ImmediatePostDominators>();
AU.setPreservesAll();
}
// stub - dummy function, just ignore it
static void stub();
};
/// ImmediatePostDominators Class - Concrete subclass of ImmediateDominatorsBase
/// that is used to compute the immediate post-dominators.
///
struct ImmediatePostDominators : public ImmediateDominatorsBase {
ImmediatePostDominators() : ImmediateDominatorsBase(true) {}
virtual bool runOnFunction(Function &F) {
IDoms.clear(); // Reset from the last time we were run...
PostDominatorSet &DS = getAnalysis<PostDominatorSet>();
Roots = DS.getRoots();
calcIDoms(DS);
return false;
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<PostDominatorSet>();
}
private:
void calcIDoms(const DominatorSetBase &DS);
};
/// PostDominatorTree Class - Concrete subclass of DominatorTree that is used to
/// compute the a post-dominator tree.
///
@@ -69,18 +85,19 @@ struct PostDominatorTree : public DominatorTreeBase {
virtual bool runOnFunction(Function &F) {
reset(); // Reset from the last time we were run...
PostDominatorSet &DS = getAnalysis<PostDominatorSet>();
Roots = DS.getRoots();
calculate(DS);
ImmediatePostDominators &IPD = getAnalysis<ImmediatePostDominators>();
Roots = IPD.getRoots();
calculate(IPD);
return false;
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<PostDominatorSet>();
AU.addRequired<ImmediatePostDominators>();
}
private:
void calculate(const PostDominatorSet &DS);
void calculate(const ImmediatePostDominators &IPD);
Node *getNodeForBlock(BasicBlock *BB);
};