This commit is for a later patch that is depend on it. The sum of two
branch probabilities can be greater than 1 due to rounding. It is safer
to saturate the results of sum and subtraction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253421
91177308-0d34-0410-b5e6-
96231b3b80d8
uint64_t scaleByInverse(uint64_t Num) const;
BranchProbability &operator+=(BranchProbability RHS) {
- assert(N <= D - RHS.N &&
- "The sum of branch probabilities should not exceed one!");
- N += RHS.N;
+ // 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 >= RHS.N &&
- "Can only subtract a smaller probability from a larger one!");
- N -= RHS.N;
+ // Saturate the result in case of underflow.
+ N = N < RHS.N ? 0 : N - RHS.N;
return *this;
}