using namespace llvm;
-/// Multiply FREQ by N and store result in W array.
-static void mult96bit(uint64_t freq, uint32_t N, uint64_t W[2]) {
- uint64_t u0 = freq & UINT32_MAX;
- uint64_t u1 = freq >> 32;
-
- // Represent 96-bit value as w[2]:w[1]:w[0];
- uint32_t w[3] = { 0, 0, 0 };
-
- uint64_t t = u0 * N;
- uint64_t k = t >> 32;
- w[0] = t;
- t = u1 * N + k;
- w[1] = t;
- w[2] = t >> 32;
-
- // W[1] - higher bits.
- // W[0] - lower bits.
- W[0] = w[0] + ((uint64_t) w[1] << 32);
- W[1] = w[2];
-}
-
-
-/// Divide 96-bit value stored in W array by D.
-/// Return 64-bit quotient, saturated to UINT64_MAX on overflow.
-static uint64_t div96bit(uint64_t W[2], uint32_t D) {
- uint64_t y = W[0];
- uint64_t x = W[1];
- unsigned i;
-
- // This long division algorithm automatically saturates on overflow.
- for (i = 0; i < 64 && x; ++i) {
- uint32_t t = (int)x >> 31;
- x = (x << 1) | (y >> 63);
- y = y << 1;
- if ((x | t) >= D) {
- x -= D;
- ++y;
- }
- }
-
- return y << (64 - i);
-}
-
-
-void BlockFrequency::scale(uint32_t N, uint32_t D) {
- assert(D != 0 && "Division by zero");
-
- // Calculate Frequency * N.
- uint64_t MulLo = (Frequency & UINT32_MAX) * N;
- uint64_t MulHi = (Frequency >> 32) * N;
- uint64_t MulRes = (MulHi << 32) + MulLo;
-
- // If the product fits in 64 bits, just use built-in division.
- if (MulHi <= UINT32_MAX && MulRes <= MulLo) {
- Frequency = MulRes / D;
- return;
- }
-
- // Product overflowed, use 96-bit operations.
- // 96-bit value represented as W[1]:W[0].
- uint64_t W[2];
- mult96bit(Frequency, N, W);
- Frequency = div96bit(W, D);
- return;
-}
-
BlockFrequency &BlockFrequency::operator*=(const BranchProbability &Prob) {
- scale(Prob.getNumerator(), Prob.getDenominator());
+ Frequency = Prob.scale(Frequency);
return *this;
}
}
BlockFrequency &BlockFrequency::operator/=(const BranchProbability &Prob) {
- scale(Prob.getDenominator(), Prob.getNumerator());
+ Frequency = Prob.scaleByInverse(Frequency);
return *this;
}
return Freq;
}
-void BlockFrequency::print(raw_ostream &OS) const {
- // Convert fixed-point number to decimal.
- OS << Frequency / getEntryFrequency() << ".";
- uint64_t Rem = Frequency % getEntryFrequency();
- uint64_t Eps = 1;
- do {
- Rem *= 10;
- Eps *= 10;
- OS << Rem / getEntryFrequency();
- Rem = Rem % getEntryFrequency();
- } while (Rem >= Eps/2);
-}
+BlockFrequency &BlockFrequency::operator>>=(const unsigned count) {
+ // Frequency can never be 0 by design.
+ assert(Frequency != 0);
-namespace llvm {
-
-raw_ostream &operator<<(raw_ostream &OS, const BlockFrequency &Freq) {
- Freq.print(OS);
- return OS;
-}
+ // Shift right by count.
+ Frequency >>= count;
+ // Saturate to 1 if we are 0.
+ Frequency |= Frequency == 0;
+ return *this;
}