[LCG] Make the return of the IntraSCC removal method actually match its

contract (and be much more useful). It now provides exactly the
post-order traversal a caller might need to perform on newly formed
SCCs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207410 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2014-04-28 10:49:06 +00:00
parent 55eab086e3
commit e52aad4202
2 changed files with 8 additions and 7 deletions

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@ -284,10 +284,8 @@ LazyCallGraph::SCC::removeIntraSCCEdge(Node &CallerN,
// First remove it from the node. // First remove it from the node.
CallerN.removeEdgeInternal(CalleeN.getFunction()); CallerN.removeEdgeInternal(CalleeN.getFunction());
// We return a list of the resulting SCCs, where 'this' is always the first // We return a list of the resulting *new* SCCs in postorder.
// element.
SmallVector<SCC *, 1> ResultSCCs; SmallVector<SCC *, 1> ResultSCCs;
ResultSCCs.push_back(this);
// Direct recursion doesn't impact the SCC graph at all. // Direct recursion doesn't impact the SCC graph at all.
if (&CallerN == &CalleeN) if (&CallerN == &CalleeN)
@ -337,7 +335,7 @@ LazyCallGraph::SCC::removeIntraSCCEdge(Node &CallerN,
} }
} }
#ifndef NDEBUG #ifndef NDEBUG
if (ResultSCCs.size() > 1) if (!ResultSCCs.empty())
assert(!IsLeafSCC && "This SCC cannot be a leaf as we have split out new " assert(!IsLeafSCC && "This SCC cannot be a leaf as we have split out new "
"SCCs by removing this edge."); "SCCs by removing this edge.");
if (!std::any_of(G->LeafSCCs.begin(), G->LeafSCCs.end(), if (!std::any_of(G->LeafSCCs.begin(), G->LeafSCCs.end(),
@ -347,7 +345,7 @@ LazyCallGraph::SCC::removeIntraSCCEdge(Node &CallerN,
#endif #endif
// If this SCC stopped being a leaf through this edge removal, remove it from // If this SCC stopped being a leaf through this edge removal, remove it from
// the leaf SCC list. // the leaf SCC list.
if (!IsLeafSCC && ResultSCCs.size() > 1) if (!IsLeafSCC && !ResultSCCs.empty())
G->LeafSCCs.erase(std::remove(G->LeafSCCs.begin(), G->LeafSCCs.end(), this), G->LeafSCCs.erase(std::remove(G->LeafSCCs.begin(), G->LeafSCCs.end(), this),
G->LeafSCCs.end()); G->LeafSCCs.end());

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@ -378,18 +378,21 @@ TEST(LazyCallGraphTest, IntraSCCEdgeRemoval) {
// Remove the edge from b -> a, which should leave the 3 functions still in // Remove the edge from b -> a, which should leave the 3 functions still in
// a single connected component because of a -> b -> c -> a. // a single connected component because of a -> b -> c -> a.
SCC.removeIntraSCCEdge(B, A); SmallVector<LazyCallGraph::SCC *, 1> NewSCCs = SCC.removeIntraSCCEdge(B, A);
EXPECT_EQ(0u, NewSCCs.size());
EXPECT_EQ(&SCC, CG1.lookupSCC(A)); EXPECT_EQ(&SCC, CG1.lookupSCC(A));
EXPECT_EQ(&SCC, CG1.lookupSCC(B)); EXPECT_EQ(&SCC, CG1.lookupSCC(B));
EXPECT_EQ(&SCC, CG1.lookupSCC(C)); EXPECT_EQ(&SCC, CG1.lookupSCC(C));
// Remove the edge from c -> a, which should leave 'a' in the original SCC // Remove the edge from c -> a, which should leave 'a' in the original SCC
// and form a new SCC for 'b' and 'c'. // and form a new SCC for 'b' and 'c'.
SCC.removeIntraSCCEdge(C, A); NewSCCs = SCC.removeIntraSCCEdge(C, A);
EXPECT_EQ(1u, NewSCCs.size());
EXPECT_EQ(&SCC, CG1.lookupSCC(A)); EXPECT_EQ(&SCC, CG1.lookupSCC(A));
EXPECT_EQ(1, std::distance(SCC.begin(), SCC.end())); EXPECT_EQ(1, std::distance(SCC.begin(), SCC.end()));
LazyCallGraph::SCC *SCC2 = CG1.lookupSCC(B); LazyCallGraph::SCC *SCC2 = CG1.lookupSCC(B);
EXPECT_EQ(SCC2, CG1.lookupSCC(C)); EXPECT_EQ(SCC2, CG1.lookupSCC(C));
EXPECT_EQ(SCC2, NewSCCs[0]);
} }
} }