+inline raw_ostream &operator<<(raw_ostream &OS, BranchProbability Prob) {
+ return Prob.print(OS);
+}
+
+inline BranchProbability operator/(BranchProbability LHS, uint32_t RHS) {
+ assert(LHS != BranchProbability::getUnknown() &&
+ "Unknown probability cannot participate in arithmetics.");
+ return BranchProbability::getRaw(LHS.getNumerator() / RHS);
+}
+
+template <class ProbabilityIter>
+void BranchProbability::normalizeProbabilities(ProbabilityIter Begin,
+ ProbabilityIter End) {
+ if (Begin == End)
+ return;
+
+ auto UnknownProbCount =
+ std::count(Begin, End, BranchProbability::getUnknown());
+ assert((UnknownProbCount == 0 ||
+ UnknownProbCount == std::distance(Begin, End)) &&
+ "Cannot normalize probabilities with known and unknown ones.");
+ (void)UnknownProbCount;
+
+ uint64_t Sum = std::accumulate(
+ Begin, End, uint64_t(0),
+ [](uint64_t S, const BranchProbability &BP) { return S + BP.N; });
+
+ if (Sum == 0) {
+ BranchProbability BP(1, std::distance(Begin, End));
+ std::fill(Begin, End, BP);
+ return;
+ }
+
+ for (auto I = Begin; I != End; ++I)
+ I->N = (I->N * uint64_t(D) + Sum / 2) / Sum;
+}
+
+template <class WeightListIter>
+void BranchProbability::normalizeEdgeWeights(WeightListIter Begin,
+ WeightListIter End) {
+ // First we compute the sum with 64-bits of precision.
+ uint64_t Sum = std::accumulate(Begin, End, uint64_t(0));
+
+ if (Sum > UINT32_MAX) {
+ // Compute the scale necessary to cause the weights to fit, and re-sum with
+ // that scale applied.
+ assert(Sum / UINT32_MAX < UINT32_MAX &&
+ "The sum of weights exceeds UINT32_MAX^2!");
+ uint32_t Scale = Sum / UINT32_MAX + 1;
+ for (auto I = Begin; I != End; ++I)
+ *I /= Scale;
+ Sum = std::accumulate(Begin, End, uint64_t(0));
+ }
+
+ // Eliminate zero weights.
+ auto ZeroWeightNum = std::count(Begin, End, 0u);
+ if (ZeroWeightNum > 0) {
+ // If all weights are zeros, replace them by 1.
+ if (Sum == 0)
+ std::fill(Begin, End, 1u);
+ else {
+ // We are converting zeros into ones, and here we need to make sure that
+ // after this the sum won't exceed UINT32_MAX.
+ if (Sum + ZeroWeightNum > UINT32_MAX) {
+ for (auto I = Begin; I != End; ++I)
+ *I /= 2;
+ ZeroWeightNum = std::count(Begin, End, 0u);
+ Sum = std::accumulate(Begin, End, uint64_t(0));
+ }
+ // Scale up non-zero weights and turn zero weights into ones.
+ uint64_t ScalingFactor = (UINT32_MAX - ZeroWeightNum) / Sum;
+ assert(ScalingFactor >= 1);
+ if (ScalingFactor > 1)
+ for (auto I = Begin; I != End; ++I)
+ *I *= ScalingFactor;
+ std::replace(Begin, End, 0u, 1u);
+ }
+ }
+}