[LCG] Switch the parent SCC tracking from a SmallSetVector to

a SmallPtrSet. Currently, there is no need for stable iteration in this
dimension, and I now thing there won't need to be going forward.

If this is ever re-introduced in any form, it needs to not be
a SetVector based solution because removal cannot be linear. There will
be many SCCs with large numbers of parents. When encountering these, the
incremental SCC update for intra-SCC edge removal was quadratic due to
linear removal (kind of).

I'm really hoping we can avoid having an ordering property here at all
though...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207091 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2014-04-24 09:22:31 +00:00
parent 9e65c46345
commit bcb39a444b
2 changed files with 4 additions and 4 deletions

View File

@ -215,7 +215,7 @@ public:
friend class LazyCallGraph;
friend class LazyCallGraph::Node;
SmallSetVector<SCC *, 1> ParentSCCs;
SmallPtrSet<SCC *, 1> ParentSCCs;
SmallVector<Node *, 1> Nodes;
SCC() {}
@ -228,7 +228,7 @@ public:
public:
typedef SmallVectorImpl<Node *>::const_iterator iterator;
typedef pointee_iterator<SmallSetVector<SCC *, 1>::const_iterator> parent_iterator;
typedef pointee_iterator<SmallPtrSet<SCC *, 1>::const_iterator> parent_iterator;
iterator begin() const { return Nodes.begin(); }
iterator end() const { return Nodes.end(); }

View File

@ -157,7 +157,7 @@ void LazyCallGraph::SCC::removeEdge(LazyCallGraph &G, Function &Caller,
// the caller no longer a parent of the callee. Walk the other call edges
// in the caller to tell.
if (!HasOtherCallToCalleeC) {
bool Removed = CalleeC.ParentSCCs.remove(this);
bool Removed = CalleeC.ParentSCCs.erase(this);
(void)Removed;
assert(Removed &&
"Did not find the caller SCC in the callee SCC's parent list!");
@ -239,7 +239,7 @@ LazyCallGraph::SCC::removeInternalEdge(LazyCallGraph &G, Node &Caller,
// However, we do need to remove this SCC from its SCC's parent set.
SCC &ChildSCC = *G.SCCMap.lookup(&ChildN);
if (&ChildSCC != this) {
ChildSCC.ParentSCCs.remove(this);
ChildSCC.ParentSCCs.erase(this);
continue;
}