E = BlockList->rend(); I != E; ++I) {
BBInfo *Info = *I;
- // Check if this block contains a newly added PHI.
- if (Info->DefBB != Info)
+ if (Info->DefBB != Info) {
+ // Record the available value at join nodes to speed up subsequent
+ // uses of this SSAUpdater for the same value.
+ if (Info->NumPreds > 1)
+ AvailableVals[Info->BB] = Info->DefBB->AvailableVal;
continue;
+ }
+
+ // Check if this block contains a newly added PHI.
PHINode *PHI = dyn_cast<PHINode>(Info->AvailableVal);
if (!PHI || PHI->getNumIncomingValues() == Info->NumPreds)
continue;