X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FBlockFrequency.cpp;h=6f7e341904b90f85c33ce4c4141ffbae2d7b52c4;hb=e8757c5dbbb50a0ac106f01360c462a3217ef62f;hp=53bbd8ad12dd232970ce6316f6ea03e65da970c5;hpb=93702a3b0754052d926c75082abf7ca156b80c45;p=oota-llvm.git

diff --git a/lib/Support/BlockFrequency.cpp b/lib/Support/BlockFrequency.cpp
index 53bbd8ad12d..6f7e341904b 100644
--- a/lib/Support/BlockFrequency.cpp
+++ b/lib/Support/BlockFrequency.cpp
@@ -18,84 +18,8 @@
 
 using namespace llvm;
 
-namespace {
-
-/// mult96bit - Multiply FREQ by N and store result in W array.
-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];
-}
-
-
-/// div96bit - Divide 96-bit value stored in W array by D. Return 64-bit frequency.
-uint64_t div96bit(uint64_t W[2], uint32_t D) {
-  uint64_t y = W[0];
-  uint64_t x = W[1];
-  int i;
-
-  for (i = 1; 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 + 1);
-}
-
-}
-
-
 BlockFrequency &BlockFrequency::operator*=(const BranchProbability &Prob) {
-  if (Frequency == 0)
-    return *this;
-
-  uint32_t n = Prob.getNumerator();
-  uint32_t d = Prob.getDenominator();
-
-  assert(n <= d && "Probability must be less or equal to 1.");
-
-  // Calculate Frequency * n.
-  uint64_t mulLo = (Frequency & UINT32_MAX) * n;
-  uint64_t mulHi = (Frequency >> 32) * n;
-  uint64_t mulRes = (mulHi << 32) + mulLo;
-
-  // If there was overflow use 96-bit operations.
-  if (mulHi > UINT32_MAX || mulRes < mulLo) {
-    // 96-bit value represented as W[1]:W[0].
-    uint64_t W[2];
-
-    // Probability is less or equal to 1 which means that results must fit
-    // 64-bit.
-    mult96bit(Frequency, n, W);
-    Frequency = div96bit(W, d);
-  } else {
-    // Fast case.
-    Frequency = mulRes / d;
-  }
-
-  // Limit the result to 1; 0 is a sentinel value. This keeps BlockFrequencyInfo
-  // from getting stuck at zero frequencies just because a value became too
-  // small to be represented as a BlockFrequency.
-  Frequency = (n == 0 || Frequency != 0) ? Frequency : 1;
+  Frequency = Prob.scale(Frequency);
   return *this;
 }
 
@@ -106,6 +30,17 @@ BlockFrequency::operator*(const BranchProbability &Prob) const {
   return Freq;
 }
 
+BlockFrequency &BlockFrequency::operator/=(const BranchProbability &Prob) {
+  Frequency = Prob.scaleByInverse(Frequency);
+  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;
@@ -124,15 +59,14 @@ BlockFrequency::operator+(const BlockFrequency &Prob) const {
   return Freq;
 }
 
-void BlockFrequency::print(raw_ostream &OS) const {
-  OS << Frequency;
-}
+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;
 }