blob: b528993d6e9346ee53a1721891d9b133394fe14c [file] [log] [blame]
Nicolas Capens2ae9d742016-11-24 14:43:05 -05001// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15#include "Optimizer.hpp"
16
17#include "src/IceCfg.h"
18#include "src/IceCfgNode.h"
19
20#include <map>
21#include <vector>
22
23namespace
24{
25 class Optimizer
26 {
27 public:
28 void run(Ice::Cfg *function);
29
30 private:
31 void analyzeUses(Ice::Cfg *function);
32 void eliminateUnusedAllocas();
33
34 Ice::Cfg *function;
35
36 std::map<Ice::Operand*, std::vector<Ice::Inst*>> uses;
37 };
38
39 void Optimizer::run(Ice::Cfg *function)
40 {
41 this->function = function;
42
43 analyzeUses(function);
44
45 eliminateUnusedAllocas();
46 }
47
48 void Optimizer::eliminateUnusedAllocas()
49 {
50 Ice::CfgNode *entryBlock = function->getEntryNode();
51
52 for(Ice::Inst &alloca : entryBlock->getInsts())
53 {
54 if(!llvm::isa<Ice::InstAlloca>(alloca))
55 {
56 return; // Allocas are all at the top
57 }
58
59 Ice::Operand *address = alloca.getDest();
60
61 if(uses[address].empty())
62 {
63 alloca.setDeleted();
64 }
65 }
66 }
67
68 void Optimizer::analyzeUses(Ice::Cfg *function)
69 {
70 uses.clear();
71
72 for(Ice::CfgNode *basicBlock : function->getNodes())
73 {
74 for(Ice::Inst &instruction : basicBlock->getInsts())
75 {
76 if(instruction.isDeleted())
77 {
78 continue;
79 }
80
81 for(int i = 0; i < instruction.getSrcSize(); i++)
82 {
83 int unique = 0;
84 for(; unique < i; unique++)
85 {
86 if(instruction.getSrc(i) == instruction.getSrc(unique))
87 {
88 break;
89 }
90 }
91
92 if(i == unique)
93 {
94 uses[instruction.getSrc(i)].push_back(&instruction);
95 }
96 }
97 }
98 }
99 }
100}
101
102namespace sw
103{
104 void optimize(Ice::Cfg *function)
105 {
106 Optimizer optimizer;
107
108 optimizer.run(function);
109 }
110}