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comparison lib/Support/BranchProbability.cpp @ 95:afa8332a0e37

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LLVM 3.8
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Tue, 13 Oct 2015 17:48:58 +0900
parents 54457678186b
children 7d135dc70f03
comparison
equal deleted inserted replaced
84:f3e34b893a5f 95:afa8332a0e37
13 13
14 #include "llvm/Support/BranchProbability.h" 14 #include "llvm/Support/BranchProbability.h"
15 #include "llvm/Support/Debug.h" 15 #include "llvm/Support/Debug.h"
16 #include "llvm/Support/Format.h" 16 #include "llvm/Support/Format.h"
17 #include "llvm/Support/raw_ostream.h" 17 #include "llvm/Support/raw_ostream.h"
18 #include <cassert>
18 19
19 using namespace llvm; 20 using namespace llvm;
20 21
22 const uint32_t BranchProbability::D;
23
21 raw_ostream &BranchProbability::print(raw_ostream &OS) const { 24 raw_ostream &BranchProbability::print(raw_ostream &OS) const {
22 return OS << N << " / " << D << " = " 25 // Get a percentage rounded to two decimal digits. This avoids
23 << format("%g%%", ((double)N / D) * 100.0); 26 // implementation-defined rounding inside printf.
27 double Percent = rint(((double)N / D) * 100.0 * 100.0) / 100.0;
28 OS << format("0x%08" PRIx32 " / 0x%08" PRIx32 " = %.2f%%", N, D, Percent);
29 return OS;
24 } 30 }
25 31
26 void BranchProbability::dump() const { print(dbgs()) << '\n'; } 32 void BranchProbability::dump() const { print(dbgs()) << '\n'; }
27 33
34 BranchProbability::BranchProbability(uint32_t Numerator, uint32_t Denominator) {
35 assert(Denominator > 0 && "Denominator cannot be 0!");
36 assert(Numerator <= Denominator && "Probability cannot be bigger than 1!");
37 if (Denominator == D)
38 N = Numerator;
39 else {
40 uint64_t Prob64 =
41 (Numerator * static_cast<uint64_t>(D) + Denominator / 2) / Denominator;
42 N = static_cast<uint32_t>(Prob64);
43 }
44 }
45
46 // If ConstD is not zero, then replace D by ConstD so that division and modulo
47 // operations by D can be optimized, in case this function is not inlined by the
48 // compiler.
49 template <uint32_t ConstD>
28 static uint64_t scale(uint64_t Num, uint32_t N, uint32_t D) { 50 static uint64_t scale(uint64_t Num, uint32_t N, uint32_t D) {
51 if (ConstD > 0)
52 D = ConstD;
53
29 assert(D && "divide by 0"); 54 assert(D && "divide by 0");
30 55
31 // Fast path for multiplying by 1.0. 56 // Fast path for multiplying by 1.0.
32 if (!Num || D == N) 57 if (!Num || D == N)
33 return Num; 58 return Num;
63 // Check for overflow. 88 // Check for overflow.
64 return Q < LowerQ ? UINT64_MAX : Q; 89 return Q < LowerQ ? UINT64_MAX : Q;
65 } 90 }
66 91
67 uint64_t BranchProbability::scale(uint64_t Num) const { 92 uint64_t BranchProbability::scale(uint64_t Num) const {
68 return ::scale(Num, N, D); 93 return ::scale<D>(Num, N, D);
69 } 94 }
70 95
71 uint64_t BranchProbability::scaleByInverse(uint64_t Num) const { 96 uint64_t BranchProbability::scaleByInverse(uint64_t Num) const {
72 return ::scale(Num, D, N); 97 return ::scale<0>(Num, D, N);
73 } 98 }