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- Eliminate provably non-pointer nodes from graphs.

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This helps a lot of testcases, for example:
            New Time  New #Nodes     Old Time    Old #Nodes
254.gap:    91.1024     21605        91.1397     22657
povray31:    2.7807      8613         3.0152     10338
255.vortex:  1.2034      8153         1.2172     8822
moria:        .6756      3150          .7054     3877
300.twolf:    .1652      2010          .1851     3270

Typically, testcases which use long and ulong integers a lot get better, f.e. povray above.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5566 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-02-14 06:28:00 +00:00
parent a3183be835
commit 5f07a8b312
1 changed files with 22 additions and 5 deletions
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27
lib/Analysis/DataStructure/DataStructure.cpp
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@ -1039,12 +1039,29 @@ void DSGraph::removeDeadNodes(unsigned Flags) {
// Mark all nodes reachable by (non-global) scalar nodes as alive...
for (hash_map<Value*, DSNodeHandle>::iterator I = ScalarMap.begin(),
E = ScalarMap.end(); I != E; ++I)
if (!isa<GlobalValue>(I->first))
I->second.getNode()->markReachableNodes(Alive);
else { // Keep track of global nodes
GlobalNodes.push_back(std::make_pair(I->first, I->second.getNode()));
E = ScalarMap.end(); I != E; )
if (isa<GlobalValue>(I->first)) { // Keep track of global nodes
assert(I->second.getNode() && "Null global node?");
GlobalNodes.push_back(std::make_pair(I->first, I->second.getNode()));
++I;
} else {
// Check to see if this is a worthless node generated for non-pointer
// values, such as integers. Consider an addition of long types: A+B.
// Assuming we can track all uses of the value in this context, and it is
// NOT used as a pointer, we can delete the node. We will be able to
// detect this situation if the node pointed to ONLY has Unknown bit set
// in the node. In this case, the node is not incomplete, does not point
// to any other nodes (no mod/ref bits set), and is therefore
// uninteresting for data structure analysis. If we run across one of
// these, prune the scalar pointing to it.
//
DSNode *N = I->second.getNode();
if (N->NodeType == DSNode::UnknownNode && !isa<Argument>(I->first)) {
ScalarMap.erase(I++);
} else {
I->second.getNode()->markReachableNodes(Alive);
++I;
}
}
// The return value is alive as well...