+CallInst *BasicBlock::getTerminatingMustTailCall() {
+ if (InstList.empty())
+ return nullptr;
+ ReturnInst *RI = dyn_cast<ReturnInst>(&InstList.back());
+ if (!RI || RI == &InstList.front())
+ return nullptr;
+
+ Instruction *Prev = RI->getPrevNode();
+ if (!Prev)
+ return nullptr;
+
+ if (Value *RV = RI->getReturnValue()) {
+ if (RV != Prev)
+ return nullptr;
+
+ // Look through the optional bitcast.
+ if (auto *BI = dyn_cast<BitCastInst>(Prev)) {
+ RV = BI->getOperand(0);
+ Prev = BI->getPrevNode();
+ if (!Prev || RV != Prev)
+ return nullptr;
+ }
+ }
+
+ if (auto *CI = dyn_cast<CallInst>(Prev)) {
+ if (CI->isMustTailCall())
+ return CI;
+ }
+ return nullptr;
+}
+