[llvm-commits] [llvm] r135992 - in /llvm/trunk: include/llvm/Support/BlockFrequency.h lib/Support/BlockFrequency.cpp lib/Support/CMakeLists.txt

[Jakub Staszak]

Author: kuba
Date: Mon Jul 25 17:24:51 2011
New Revision: 135992

URL: http://llvm.org/viewvc/llvm-project?rev=135992&view=rev
Log:
Add BlockFrequency class.

Added:
    llvm/trunk/include/llvm/Support/BlockFrequency.h
    llvm/trunk/lib/Support/BlockFrequency.cpp
Modified:
    llvm/trunk/lib/Support/CMakeLists.txt

Added: llvm/trunk/include/llvm/Support/BlockFrequency.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/BlockFrequency.h?rev=135992&view=auto
==============================================================================
--- llvm/trunk/include/llvm/Support/BlockFrequency.h (added)
+++ llvm/trunk/include/llvm/Support/BlockFrequency.h Mon Jul 25 17:24:51 2011
@@ -0,0 +1,64 @@
+//===-------- BlockFrequency.h - Block Frequency Wrapper --------*- 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.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_BLOCKFREQUENCY_H
+#define LLVM_SUPPORT_BLOCKFREQUENCY_H
+
+namespace llvm {
+
+class raw_ostream;
+class BranchProbability;
+
+// This class represents Block Frequency as a 64-bit value.
+class BlockFrequency {
+
+  uint64_t Frequency;
+
+  static void mult96bit(uint64_t freq, uint32_t N, uint64_t W[2]);
+  static uint64_t div96bit(uint64_t W[2], uint32_t D);
+
+public:
+  BlockFrequency(uint64_t Freq = 0) : Frequency(Freq) { }
+
+  uint64_t getFrequency() const { return Frequency; }
+
+  BlockFrequency &operator*=(const BranchProbability &Prob);
+  const BlockFrequency operator*(const BranchProbability &Prob) const;
+
+  BlockFrequency &operator+=(const BlockFrequency &Freq);
+  const BlockFrequency operator+(const BlockFrequency &Freq) const;
+
+  bool operator<(const BlockFrequency &RHS) const {
+    return Frequency < RHS.Frequency;
+  }
+
+  bool operator<=(const BlockFrequency &RHS) const {
+    return Frequency <= RHS.Frequency;
+  }
+
+  bool operator>(const BlockFrequency &RHS) const {
+    return Frequency > RHS.Frequency;
+  }
+
+  bool operator>=(const BlockFrequency &RHS) const {
+    return Frequency >= RHS.Frequency;
+  }
+
+  void print(raw_ostream &OS) const;
+};
+
+raw_ostream &operator<<(raw_ostream &OS, const BlockFrequency &Freq);
+
+}
+
+#endif

Added: llvm/trunk/lib/Support/BlockFrequency.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/BlockFrequency.cpp?rev=135992&view=auto
==============================================================================
--- llvm/trunk/lib/Support/BlockFrequency.cpp (added)
+++ llvm/trunk/lib/Support/BlockFrequency.cpp Mon Jul 25 17:24:51 2011
@@ -0,0 +1,120 @@
+//====--------------- 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;
+
+/// mult96bit - Multiply FREQ by N and store result in W array.
+void BlockFrequency::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 BlockFrequency::div96bit(uint64_t W[2], uint32_t D) {
+  uint64_t y = W[0];
+  uint64_t x = W[1];
+
+  for (int i = 1; i <= 64; ++i) {
+    uint32_t t = (int)x >> 31;
+    x = (x << 1) | (y >> 63);
+    y = y << 1;
+    if ((x | t) >= D) {
+      x -= D;
+      ++y;
+    }
+  }
+
+  return y;
+}
+
+BlockFrequency &BlockFrequency::operator*=(const BranchProbability &Prob) {
+  uint32_t n = Prob.getNumerator();
+  uint32_t d = Prob.getDenominator();
+
+  assert(n <= d && "Probability must be less or equal to 1.");
+
+  // If we can overflow use 96-bit operations.
+  if (n > 0 && Frequency > UINT64_MAX / n) {
+    // 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);
+    return *this;
+  }
+
+  Frequency *= n;
+  Frequency /= d;
+  return *this;
+}
+
+const 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;
+}
+
+void BlockFrequency::print(raw_ostream &OS) const {
+  OS << Frequency;
+}
+
+namespace llvm {
+
+raw_ostream &operator<<(raw_ostream &OS, const BlockFrequency &Freq) {
+  Freq.print(OS);
+  return OS;
+}
+
+}

Modified: llvm/trunk/lib/Support/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/CMakeLists.txt?rev=135992&r1=135991&r2=135992&view=diff
==============================================================================
--- llvm/trunk/lib/Support/CMakeLists.txt (original)
+++ llvm/trunk/lib/Support/CMakeLists.txt Mon Jul 25 17:24:51 2011
@@ -9,6 +9,7 @@
   APInt.cpp
   APSInt.cpp
   Allocator.cpp
+  BlockFrequency.cpp
   BranchProbability.cpp
   circular_raw_ostream.cpp
   CommandLine.cpp