[PGO] Add support for reading multiple versions of indexed profile format profile...

[oota-llvm.git] / include / llvm / Support / BranchProbability.h

diff --git a/include/llvm/Support/BranchProbability.h b/include/llvm/Support/BranchProbability.h
index 1ca94ca3196fc50b372e10712a6404eac853cdf1..2548384f346b6a0c7b52c1060ca43c2950d8d668 100644 (file)
--- a/include/llvm/Support/BranchProbability.h
+++ b/include/llvm/Support/BranchProbability.h
@@ -41,7 +41,7 @@ class BranchProbability {
   explicit BranchProbability(uint32_t n) : N(n) {}
 
 public:
-  BranchProbability() : N(0) {}
+  BranchProbability() : N(UnknownN) {}
   BranchProbability(uint32_t Numerator, uint32_t Denominator);
 
   bool isZero() const { return N == 0; }
@@ -53,6 +53,9 @@ public:
   // Create a BranchProbability object with the given numerator and 1<<31
   // as denominator.
   static BranchProbability getRaw(uint32_t N) { return BranchProbability(N); }
+  // Create a BranchProbability object from 64-bit integers.
+  static BranchProbability getBranchProbability(uint64_t Numerator,
+                                                uint64_t Denominator);
 
   // Normalize given probabilties so that the sum of them becomes approximate
   // one.
@@ -92,18 +95,24 @@ public:
   uint64_t scaleByInverse(uint64_t Num) const;
 
   BranchProbability &operator+=(BranchProbability RHS) {
+    assert(N != UnknownN && RHS.N != UnknownN &&
+           "Unknown probability cannot participate in arithmetics.");
     // Saturate the result in case of overflow.
     N = (uint64_t(N) + RHS.N > D) ? D : N + RHS.N;
     return *this;
   }
 
   BranchProbability &operator-=(BranchProbability RHS) {
+    assert(N != UnknownN && RHS.N != UnknownN &&
+           "Unknown probability cannot participate in arithmetics.");
     // Saturate the result in case of underflow.
     N = N < RHS.N ? 0 : N - RHS.N;
     return *this;
   }
 
   BranchProbability &operator*=(BranchProbability RHS) {
+    assert(N != UnknownN && RHS.N != UnknownN &&
+           "Unknown probability cannot participate in arithmetics.");
     N = (static_cast<uint64_t>(N) * RHS.N + D / 2) / D;
     return *this;
   }
@@ -125,10 +134,30 @@ public:
 
   bool operator==(BranchProbability RHS) const { return N == RHS.N; }
   bool operator!=(BranchProbability RHS) const { return !(*this == RHS); }
-  bool operator<(BranchProbability RHS) const { return N < RHS.N; }
-  bool operator>(BranchProbability RHS) const { return RHS < *this; }
-  bool operator<=(BranchProbability RHS) const { return !(RHS < *this); }
-  bool operator>=(BranchProbability RHS) const { return !(*this < RHS); }
+
+  bool operator<(BranchProbability RHS) const {
+    assert(N != UnknownN && RHS.N != UnknownN &&
+           "Unknown probability cannot participate in comparisons.");
+    return N < RHS.N;
+  }
+
+  bool operator>(BranchProbability RHS) const {
+    assert(N != UnknownN && RHS.N != UnknownN &&
+           "Unknown probability cannot participate in comparisons.");
+    return RHS < *this;
+  }
+
+  bool operator<=(BranchProbability RHS) const {
+    assert(N != UnknownN && RHS.N != UnknownN &&
+           "Unknown probability cannot participate in comparisons.");
+    return !(RHS < *this);
+  }
+
+  bool operator>=(BranchProbability RHS) const {
+    assert(N != UnknownN && RHS.N != UnknownN &&
+           "Unknown probability cannot participate in comparisons.");
+    return !(*this < RHS);
+  }
 };
 
 inline raw_ostream &operator<<(raw_ostream &OS, BranchProbability Prob) {
@@ -136,6 +165,8 @@ inline raw_ostream &operator<<(raw_ostream &OS, BranchProbability Prob) {
 }
 
 inline BranchProbability operator/(BranchProbability LHS, uint32_t RHS) {
+  assert(LHS != BranchProbability::getUnknown() &&
+         "Unknown probability cannot participate in arithmetics.");
   return BranchProbability::getRaw(LHS.getNumerator() / RHS);
 }
 
@@ -145,10 +176,23 @@ void BranchProbability::normalizeProbabilities(ProbabilityIter Begin,
   if (Begin == End)
     return;
 
-  uint64_t Sum = 0;
-  for (auto I = Begin; I != End; ++I)
-    Sum += I->N;
-  assert(Sum > 0);
+  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;
 }