+/// Update the dominator tree after if-conversion erased some blocks.
+void EarlyIfConverter::updateDomTree(ArrayRef<MachineBasicBlock*> Removed) {
+ // convertIf can remove TBB, FBB, and Tail can be merged into Head.
+ // TBB and FBB should not dominate any blocks.
+ // Tail children should be transferred to Head.
+ MachineDomTreeNode *HeadNode = DomTree->getNode(IfConv.Head);
+ for (unsigned i = 0, e = Removed.size(); i != e; ++i) {
+ MachineDomTreeNode *Node = DomTree->getNode(Removed[i]);
+ assert(Node != HeadNode && "Cannot erase the head node");
+ while (Node->getNumChildren()) {
+ assert(Node->getBlock() == IfConv.Tail && "Unexpected children");
+ DomTree->changeImmediateDominator(Node->getChildren().back(), HeadNode);
+ }
+ DomTree->eraseNode(Removed[i]);
+ }
+}
+
+/// Update LoopInfo after if-conversion.
+void EarlyIfConverter::updateLoops(ArrayRef<MachineBasicBlock*> Removed) {
+ if (!Loops)
+ return;
+ // If-conversion doesn't change loop structure, and it doesn't mess with back
+ // edges, so updating LoopInfo is simply removing the dead blocks.
+ for (unsigned i = 0, e = Removed.size(); i != e; ++i)
+ Loops->removeBlock(Removed[i]);
+}
+
+/// Invalidate MachineTraceMetrics before if-conversion.
+void EarlyIfConverter::invalidateTraces() {
+ Traces->verifyAnalysis();
+ Traces->invalidate(IfConv.Head);
+ Traces->invalidate(IfConv.Tail);
+ Traces->invalidate(IfConv.TBB);
+ Traces->invalidate(IfConv.FBB);
+ Traces->verifyAnalysis();
+}
+
+// Adjust cycles with downward saturation.
+static unsigned adjCycles(unsigned Cyc, int Delta) {
+ if (Delta < 0 && Cyc + Delta > Cyc)
+ return 0;
+ return Cyc + Delta;
+}
+
+/// Apply cost model and heuristics to the if-conversion in IfConv.
+/// Return true if the conversion is a good idea.