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// OptimizeWorkItemFuncCalls is an LLVM pass to optimize calls to work-item
// functions like get_local_size().
//
// Copyright (c) 2017-2019 Pekka Jääskeläinen
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
#include "CompilerWarnings.h"
IGNORE_COMPILER_WARNING("-Wmaybe-uninitialized")
#include <llvm/ADT/Twine.h>
POP_COMPILER_DIAGS
IGNORE_COMPILER_WARNING("-Wunused-parameter")
#include <llvm/IR/Constants.h>
#include <llvm/IR/Instructions.h>
#include "LLVMUtils.h"
#include "OptimizeWorkItemFuncCalls.h"
#include "VariableUniformityAnalysis.h"
#include "WorkitemHandlerChooser.h"
POP_COMPILER_DIAGS
#include <iostream>
#include <map>
#include <set>
#define PASS_NAME "optimize-wi-func-calls"
#define PASS_CLASS pocl::OptimizeWorkItemFuncCalls
#define PASS_DESC "Optimize work-item function calls."
namespace pocl {
using namespace llvm;
static bool optimizeWorkItemFuncCalls(Function &F) {
// Let's avoid reoptimizing pocl_printf in the kernel compiler. It should
// be optimized already in the bitcode library, and we do not want to
// aggressively inline it to the kernel, causing compile time expansion.
if (F.getName().startswith("__pocl_print") &&
!F.hasFnAttribute(Attribute::OptimizeNone)) {
F.addFnAttr(Attribute::OptimizeNone);
F.addFnAttr(Attribute::NoInline);
}
if (F.getName().startswith("_") || F.hasFnAttribute(Attribute::OptimizeNone))
return false;
// Find calls to WI functions and unify them to a single call in the
// entry to avoid confusing LLVM later with the 'pseudo loads' and to
// reduce the inlining bloat.
Function::iterator I = F.begin();
Instruction *FirstInsnPt = &*(I++)->getFirstInsertionPt();
bool Changed = false;
std::map<std::string, std::vector<CallInst*>> Calls;
// First collect all calls of interest.
for (Function::iterator E = F.end(); I != E; ++I) {
for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;) {
CallInst *Call = dyn_cast<CallInst>(BI++);
if (Call == nullptr) continue;
if (Call->getCalledFunction() == nullptr) {
// The callee can be null in case of asm snippets (TCE).
continue;
}
std::string FuncName = Call->getCalledFunction()->getName().str();
auto FuncNameI =
std::find(WIFuncNameVec.begin(), WIFuncNameVec.end(), FuncName);
if (FuncNameI == WIFuncNameVec.end())
continue;
bool Unsupported = false;
// Check that the argument list is something we can handle.
const unsigned CallNumArg = Call->arg_size();
for (unsigned I = 0; I < CallNumArg; ++I) {
llvm::ConstantInt *CallOperand =
dyn_cast<llvm::ConstantInt>(Call->getArgOperand(I));
if (CallOperand == nullptr)
Unsupported = true;
}
if (Unsupported) continue;
Calls[FuncName].push_back(Call);
}
}
// Add single calls for the interesting functions.
std::map<std::string, std::vector<CallInst*> > CallsInEntry;
for (const auto &Call : Calls) {
std::string FuncName = Call.first;
auto CallInsts = Call.second;
for (auto CallInst : CallInsts) {
// Try to find a previous call with the same parameters which
// we can reuse.
std::vector<llvm::CallInst*> &CallsMoved = CallsInEntry[FuncName];
llvm::CallInst *PreviousCall = nullptr;
for (auto &M : CallsMoved) {
llvm::CallInst *MovedCall = dyn_cast<llvm::CallInst>(M);
// WI functions do not have variable argument lists.
const unsigned MovedCallNumArg = MovedCall->arg_size();
assert(MovedCallNumArg == CallInst->arg_size());
bool IsApplicable = true;
for (unsigned I = 0; I < MovedCallNumArg; ++I) {
llvm::ConstantInt *CallOperand =
dyn_cast<llvm::ConstantInt>(CallInst->getArgOperand(I));
llvm::ConstantInt *PrevCallOperand =
dyn_cast<llvm::ConstantInt>(MovedCall->getArgOperand(I));
assert (isa<llvm::ConstantInt>(PrevCallOperand));
if (CallOperand->getValue() != PrevCallOperand->getValue()) {
IsApplicable = false;
break;
}
}
if (IsApplicable) {
// Found a suitable previous call instruction we can reuse.
PreviousCall = MovedCall;
break;
}
}
if (PreviousCall == nullptr) {
CallInst->moveBefore(FirstInsnPt);
CallsInEntry[FuncName].push_back(CallInst);
Changed = true;
} else {
// Not the first call. Refer to the first call that was moved to
// the entry.
CallInst->replaceAllUsesWith(PreviousCall);
CallInst->eraseFromParent();
Changed = true;
}
}
}
return Changed;
}
#if LLVM_MAJOR < MIN_LLVM_NEW_PASSMANAGER
char OptimizeWorkItemFuncCalls::ID = 0;
bool OptimizeWorkItemFuncCalls::runOnFunction(Function &F) {
return optimizeWorkItemFuncCalls(F);
}
void OptimizeWorkItemFuncCalls::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addPreserved<WorkitemHandlerChooser>();
}
REGISTER_OLD_FPASS(PASS_NAME, PASS_CLASS, PASS_DESC);
#else
llvm::PreservedAnalyses
OptimizeWorkItemFuncCalls::run(llvm::Function &F,
llvm::FunctionAnalysisManager &AM) {
PreservedAnalyses PAChanged = PreservedAnalyses::none();
PAChanged.preserve<WorkitemHandlerChooser>();
return optimizeWorkItemFuncCalls(F) ? PAChanged : PreservedAnalyses::all();
}
REGISTER_NEW_FPASS(PASS_NAME, PASS_CLASS, PASS_DESC);
#endif
} // namespace pocl
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