Eliminate unused allocas.
Bug swiftshader:27
Change-Id: If085323dc6cc4325c6ff55c1021e98db94a75302
Reviewed-on: https://swiftshader-review.googlesource.com/8228
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
diff --git a/src/Reactor/Optimizer.cpp b/src/Reactor/Optimizer.cpp
new file mode 100644
index 0000000..b528993
--- /dev/null
+++ b/src/Reactor/Optimizer.cpp
@@ -0,0 +1,110 @@
+// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "Optimizer.hpp"
+
+#include "src/IceCfg.h"
+#include "src/IceCfgNode.h"
+
+#include <map>
+#include <vector>
+
+namespace
+{
+ class Optimizer
+ {
+ public:
+ void run(Ice::Cfg *function);
+
+ private:
+ void analyzeUses(Ice::Cfg *function);
+ void eliminateUnusedAllocas();
+
+ Ice::Cfg *function;
+
+ std::map<Ice::Operand*, std::vector<Ice::Inst*>> uses;
+ };
+
+ void Optimizer::run(Ice::Cfg *function)
+ {
+ this->function = function;
+
+ analyzeUses(function);
+
+ eliminateUnusedAllocas();
+ }
+
+ void Optimizer::eliminateUnusedAllocas()
+ {
+ Ice::CfgNode *entryBlock = function->getEntryNode();
+
+ for(Ice::Inst &alloca : entryBlock->getInsts())
+ {
+ if(!llvm::isa<Ice::InstAlloca>(alloca))
+ {
+ return; // Allocas are all at the top
+ }
+
+ Ice::Operand *address = alloca.getDest();
+
+ if(uses[address].empty())
+ {
+ alloca.setDeleted();
+ }
+ }
+ }
+
+ void Optimizer::analyzeUses(Ice::Cfg *function)
+ {
+ uses.clear();
+
+ for(Ice::CfgNode *basicBlock : function->getNodes())
+ {
+ for(Ice::Inst &instruction : basicBlock->getInsts())
+ {
+ if(instruction.isDeleted())
+ {
+ continue;
+ }
+
+ for(int i = 0; i < instruction.getSrcSize(); i++)
+ {
+ int unique = 0;
+ for(; unique < i; unique++)
+ {
+ if(instruction.getSrc(i) == instruction.getSrc(unique))
+ {
+ break;
+ }
+ }
+
+ if(i == unique)
+ {
+ uses[instruction.getSrc(i)].push_back(&instruction);
+ }
+ }
+ }
+ }
+ }
+}
+
+namespace sw
+{
+ void optimize(Ice::Cfg *function)
+ {
+ Optimizer optimizer;
+
+ optimizer.run(function);
+ }
+}
\ No newline at end of file
diff --git a/src/Reactor/Optimizer.hpp b/src/Reactor/Optimizer.hpp
new file mode 100644
index 0000000..c050717
--- /dev/null
+++ b/src/Reactor/Optimizer.hpp
@@ -0,0 +1,25 @@
+// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef sw_Optimizer_hpp
+#define sw_Optimizer_hpp
+
+#include "src/IceCfg.h"
+
+namespace sw
+{
+ void optimize(Ice::Cfg *function);
+}
+
+#endif // sw_Optimizer_hpp
diff --git a/src/Reactor/Subzero.vcxproj b/src/Reactor/Subzero.vcxproj
index 2a11524..59c1669 100644
--- a/src/Reactor/Subzero.vcxproj
+++ b/src/Reactor/Subzero.vcxproj
@@ -204,6 +204,7 @@
<ClCompile Include="$(SolutionDir)third_party\pnacl-subzero\src\IceTimerTree.cpp" />
<ClCompile Include="$(SolutionDir)third_party\pnacl-subzero\src\IceTypes.cpp" />
<ClCompile Include="$(SolutionDir)third_party\pnacl-subzero\src\IceVariableSplitting.cpp" />
+ <ClCompile Include="Optimizer.cpp" />
<ClCompile Include="Routine.cpp" />
<ClCompile Include="SubzeroReactor.cpp" />
</ItemGroup>
@@ -264,6 +265,7 @@
<ClInclude Include="$(SolutionDir)third_party\pnacl-subzero\src\IceConditionCodesX8664.h" />
<ClInclude Include="$(SolutionDir)third_party\pnacl-subzero\src\IceInstX8664.h" />
<ClInclude Include="$(SolutionDir)third_party\pnacl-subzero\src\IceRegistersX8664.h" />
+ <ClInclude Include="Optimizer.hpp" />
</ItemGroup>
<ItemGroup>
<None Include="$(SolutionDir)third_party\pnacl-subzero\src\IceClFlags.def" />
diff --git a/src/Reactor/Subzero.vcxproj.filters b/src/Reactor/Subzero.vcxproj.filters
index b415ca1..64c9db6 100644
--- a/src/Reactor/Subzero.vcxproj.filters
+++ b/src/Reactor/Subzero.vcxproj.filters
@@ -117,6 +117,9 @@
<ClCompile Include="$(SolutionDir)third_party\pnacl-subzero\src\IceTargetLoweringX8664.cpp">
<Filter>Source Files</Filter>
</ClCompile>
+ <ClCompile Include="Optimizer.cpp">
+ <Filter>Source Files</Filter>
+ </ClCompile>
</ItemGroup>
<ItemGroup>
<ClInclude Include="$(SolutionDir)third_party\pnacl-subzero\src\IceAssembler.h">
@@ -287,6 +290,9 @@
<ClInclude Include="$(SolutionDir)third_party\pnacl-subzero\src\IceRegistersX8664.h">
<Filter>Header Files</Filter>
</ClInclude>
+ <ClInclude Include="Optimizer.hpp">
+ <Filter>Header Files</Filter>
+ </ClInclude>
</ItemGroup>
<ItemGroup>
<None Include="$(SolutionDir)third_party\pnacl-subzero\src\IceClFlags.def">
diff --git a/src/Reactor/SubzeroReactor.cpp b/src/Reactor/SubzeroReactor.cpp
index da66206..aacec93 100644
--- a/src/Reactor/SubzeroReactor.cpp
+++ b/src/Reactor/SubzeroReactor.cpp
@@ -17,6 +17,8 @@
#include "Reactor.hpp"
#include "Routine.hpp"
+#include "Optimizer.hpp"
+
#include "src/IceTypes.h"
#include "src/IceCfg.h"
#include "src/IceELFStreamer.h"
@@ -422,6 +424,8 @@
std::string asciiName(wideName.begin(), wideName.end());
::function->setFunctionName(Ice::GlobalString::createWithString(::context, asciiName));
+ optimize();
+
::function->translate();
assert(!::function->hasError());
@@ -449,6 +453,7 @@
void Nucleus::optimize()
{
+ sw::optimize(::function);
}
Value *Nucleus::allocateStackVariable(Type *t, int arraySize)
