private static Block calcBlockForUsage(
Node node, Node usage, Block startBlock, NodeMap<Block> currentNodeMap) {
assert !(node instanceof PhiNode);
Block currentBlock = startBlock;
if (usage instanceof PhiNode) {
// An input to a PhiNode is used at the end of the predecessor block that
// corresponds to the PhiNode input. One PhiNode can use an input multiple times.
PhiNode phi = (PhiNode) usage;
AbstractMergeNode merge = phi.merge();
Block mergeBlock = currentNodeMap.get(merge);
for (int i = 0; i < phi.valueCount(); ++i) {
if (phi.valueAt(i) == node) {
Block otherBlock = mergeBlock.getPredecessors()[i];
currentBlock = AbstractControlFlowGraph.commonDominatorTyped(currentBlock, otherBlock);
}
}
} else if (usage instanceof AbstractBeginNode) {
AbstractBeginNode abstractBeginNode = (AbstractBeginNode) usage;
if (abstractBeginNode instanceof StartNode) {
currentBlock =
AbstractControlFlowGraph.commonDominatorTyped(
currentBlock, currentNodeMap.get(abstractBeginNode));
} else {
Block otherBlock = currentNodeMap.get(abstractBeginNode).getDominator();
currentBlock = AbstractControlFlowGraph.commonDominatorTyped(currentBlock, otherBlock);
}
} else {
// All other types of usages: Put the input into the same block as the usage.
Block otherBlock = currentNodeMap.get(usage);
currentBlock = AbstractControlFlowGraph.commonDominatorTyped(currentBlock, otherBlock);
}
return currentBlock;
}
public static void checkRedundantPhi(PhiNode phiNode) {
if (phiNode.isDeleted() || phiNode.valueCount() == 1) {
return;
}
ValueNode singleValue = phiNode.singleValue();
if (singleValue != null) {
Collection<PhiNode> phiUsages = phiNode.usages().filter(PhiNode.class).snapshot();
Collection<ProxyNode> proxyUsages = phiNode.usages().filter(ProxyNode.class).snapshot();
phiNode.graph().replaceFloating(phiNode, singleValue);
for (PhiNode phi : phiUsages) {
checkRedundantPhi(phi);
}
for (ProxyNode proxy : proxyUsages) {
checkRedundantProxy(proxy);
}
}
}