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authorChandler Carruth <chandlerc@gmail.com>2014-04-25 06:38:58 +0000
committerChandler Carruth <chandlerc@gmail.com>2014-04-25 06:38:58 +0000
commitfe0f0187be88afc697514c0626fa2c4ba87b7466 (patch)
treecea1b94f231ddf3f4952cf8d1420214f61a8249b /lib
parent64b54708667aef1ec4a0e19067f89876f7dde048 (diff)
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[LCG] Now that the loop structure of the core SCC finding routine is
factored into a more reasonable form, replace the tail call with a simple outer-loop continuation. It's sad that C++ makes this so awkward to write, but it seems more direct and clear than the tail call at this point. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207201 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r--lib/Analysis/LazyCallGraph.cpp9
1 files changed, 8 insertions, 1 deletions
diff --git a/lib/Analysis/LazyCallGraph.cpp b/lib/Analysis/LazyCallGraph.cpp
index 2e4fad3996..c9cc0dd4ec 100644
--- a/lib/Analysis/LazyCallGraph.cpp
+++ b/lib/Analysis/LazyCallGraph.cpp
@@ -449,6 +449,7 @@ LazyCallGraph::SCC *LazyCallGraph::getNextSCCInPostOrder() {
assert(N->DFSNumber != 0 && "We should always assign a DFS number "
"before placing a node onto the stack.");
+ bool Recurse = false; // Used to simulate recursing onto a child.
for (auto I = DFSStack.back().second, E = N->end(); I != E; ++I) {
Node &ChildN = *I;
if (ChildN.DFSNumber == 0) {
@@ -463,7 +464,8 @@ LazyCallGraph::SCC *LazyCallGraph::getNextSCCInPostOrder() {
ChildN.LowLink = ChildN.DFSNumber = NextDFSNumber++;
SCCEntryNodes.remove(&ChildN.getFunction());
DFSStack.push_back(std::make_pair(&ChildN, ChildN.begin()));
- return LazyCallGraph::getNextSCCInPostOrder();
+ Recurse = true;
+ break;
}
// Track the lowest link of the childen, if any are still in the stack.
@@ -472,6 +474,11 @@ LazyCallGraph::SCC *LazyCallGraph::getNextSCCInPostOrder() {
if (ChildN.LowLink >= 0 && ChildN.LowLink < N->LowLink)
N->LowLink = ChildN.LowLink;
}
+ if (Recurse)
+ // Continue the outer loop when we exit the inner loop in order to
+ // recurse onto a child.
+ continue;
+
// No more children to process here, pop the node off the stack.
DFSStack.pop_back();