1 files changed, 172 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Support/BlockFrequency.cpp b/contrib/llvm/lib/Support/BlockFrequency.cpp
new file mode 100644
index 000000000000..00efe90a2607
--- /dev/null
+++ b/contrib/llvm/lib/Support/BlockFrequency.cpp
@@ -0,0 +1,172 @@
+//====--------------- lib/Support/BlockFrequency.cpp -----------*- C++ -*-====//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements Block Frequency class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/BranchProbability.h"
+#include "llvm/Support/BlockFrequency.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cassert>
+
+using namespace llvm;
+
+/// Multiply FREQ by N and store result in W array.
+static void mult96bit(uint64_t freq, uint32_t N, uint32_t W[3]) {
+  uint64_t u0 = freq & UINT32_MAX;
+  uint64_t u1 = freq >> 32;
+
+  // Represent 96-bit value as W[2]:W[1]:W[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;
+}
+
+/// Divide 96-bit value stored in W[2]:W[1]:W[0] by D. Since our word size is a
+/// 32 bit unsigned integer, we can use a short division algorithm.
+static uint64_t divrem96bit(uint32_t W[3], uint32_t D, uint32_t *Rout) {
+  // We assume that W[2] is non-zero since if W[2] is not then the user should
+  // just use hardware division.
+  assert(W[2] && "This routine assumes that W[2] is non-zero since if W[2] is "
+         "zero, the caller should just use 64/32 hardware.");
+  uint32_t Q[3] = { 0, 0, 0 };
+
+  // The generalized short division algorithm sets i to m + n - 1, where n is
+  // the number of words in the divisior and m is the number of words by which
+  // the divident exceeds the divisor (i.e. m + n == the length of the dividend
+  // in words). Due to our assumption that W[2] is non-zero, we know that the
+  // dividend is of length 3 implying since n is 1 that m = 2. Thus we set i to
+  // m + n - 1 = 2 + 1 - 1 = 2.
+  uint32_t R = 0;
+  for (int i = 2; i >= 0; --i) {
+    uint64_t PartialD = uint64_t(R) << 32 | W[i];
+    if (PartialD == 0) {
+      Q[i] = 0;
+      R = 0;
+    } else if (PartialD < D) {
+      Q[i] = 0;
+      R = uint32_t(PartialD);
+    } else if (PartialD == D) {
+      Q[i] = 1;
+      R = 0;
+    } else {
+      Q[i] = uint32_t(PartialD / D);
+      R = uint32_t(PartialD - (Q[i] * D));
+    }
+  }
+
+  // If Q[2] is non-zero, then we overflowed.
+  uint64_t Result;
+  if (Q[2]) {
+    Result = UINT64_MAX;
+    R = D;
+  } else {
+    // Form the final uint64_t result, avoiding endianness issues.
+    Result = uint64_t(Q[0]) | (uint64_t(Q[1]) << 32);
+  }
+
+  if (Rout)
+    *Rout = R;
+
+  return Result;
+}
+
+uint32_t 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 MulRes % D;
+  }
+
+  // Product overflowed, use 96-bit operations.
+  // 96-bit value represented as W[2]:W[1]:W[0].
+  uint32_t W[3];
+  uint32_t R;
+  mult96bit(Frequency, N, W);
+  Frequency = divrem96bit(W, D, &R);
+  return R;
+}
+
+BlockFrequency &BlockFrequency::operator*=(const BranchProbability &Prob) {
+  scale(Prob.getNumerator(), Prob.getDenominator());
+  return *this;
+}
+
+const BlockFrequency
+BlockFrequency::operator*(const BranchProbability &Prob) const {
+  BlockFrequency Freq(Frequency);
+  Freq *= Prob;
+  return Freq;
+}
+
+BlockFrequency &BlockFrequency::operator/=(const BranchProbability &Prob) {
+  scale(Prob.getDenominator(), Prob.getNumerator());
+  return *this;
+}
+
+BlockFrequency BlockFrequency::operator/(const BranchProbability &Prob) const {
+  BlockFrequency Freq(Frequency);
+  Freq /= Prob;
+  return Freq;
+}
+
+BlockFrequency &BlockFrequency::operator+=(const BlockFrequency &Freq) {
+  uint64_t Before = Freq.Frequency;
+  Frequency += Freq.Frequency;
+
+  // If overflow, set frequency to the maximum value.
+  if (Frequency < Before)
+    Frequency = UINT64_MAX;
+
+  return *this;
+}
+
+const BlockFrequency
+BlockFrequency::operator+(const BlockFrequency &Prob) const {
+  BlockFrequency Freq(Frequency);
+  Freq += Prob;
+  return Freq;
+}
+
+uint32_t BlockFrequency::scale(const BranchProbability &Prob) {
+  return scale(Prob.getNumerator(), Prob.getDenominator());
+}
+
+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);
+}
+
+namespace llvm {
+
+raw_ostream &operator<<(raw_ostream &OS, const BlockFrequency &Freq) {
+  Freq.print(OS);
+  return OS;
+}
+
+}