//===-- SPIRVStripConvergentIntrinsics.cpp ----------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This pass trims convergence intrinsics as those were only useful when
// modifying the CFG during IR passes.
//
//===----------------------------------------------------------------------===//
#include "SPIRV.h"
#include "SPIRVSubtarget.h"
#include "SPIRVTargetMachine.h"
#include "SPIRVUtils.h"
#include "llvm/CodeGen/IntrinsicLowering.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IntrinsicsSPIRV.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/LowerMemIntrinsics.h"
using namespace llvm;
namespace llvm {
void initializeSPIRVStripConvergentIntrinsicsPass(PassRegistry &);
}
class SPIRVStripConvergentIntrinsics : public FunctionPass {
public:
static char ID;
SPIRVStripConvergentIntrinsics() : FunctionPass(ID) {
initializeSPIRVStripConvergentIntrinsicsPass(
*PassRegistry::getPassRegistry());
};
virtual bool runOnFunction(Function &F) override {
DenseSet<Instruction *> ToRemove;
// Is the instruction is a convergent intrinsic, add it to kill-list and
// returns true. Returns false otherwise.
auto CleanupIntrinsic = [&](IntrinsicInst *II) {
if (II->getIntrinsicID() != Intrinsic::experimental_convergence_entry &&
II->getIntrinsicID() != Intrinsic::experimental_convergence_loop &&
II->getIntrinsicID() != Intrinsic::experimental_convergence_anchor)
return false;
II->replaceAllUsesWith(UndefValue::get(II->getType()));
ToRemove.insert(II);
return true;
};
// Replace the given CallInst by a similar CallInst with no convergencectrl
// attribute.
auto CleanupCall = [&](CallInst *CI) {
auto OB = CI->getOperandBundle(LLVMContext::OB_convergencectrl);
if (!OB.has_value())
return;
auto *NewCall = CallBase::removeOperandBundle(
CI, LLVMContext::OB_convergencectrl, CI->getIterator());
NewCall->copyMetadata(*CI);
CI->replaceAllUsesWith(NewCall);
ToRemove.insert(CI);
};
for (BasicBlock &BB : F) {
for (Instruction &I : BB) {
if (auto *II = dyn_cast<IntrinsicInst>(&I))
if (CleanupIntrinsic(II))
continue;
if (auto *CI = dyn_cast<CallInst>(&I))
CleanupCall(CI);
}
}
// All usages must be removed before their definition is removed.
for (Instruction *I : ToRemove)
I->eraseFromParent();
return ToRemove.size() != 0;
}
};
char SPIRVStripConvergentIntrinsics::ID = 0;
INITIALIZE_PASS(SPIRVStripConvergentIntrinsics, "strip-convergent-intrinsics",
"SPIRV strip convergent intrinsics", false, false)
FunctionPass *llvm::createSPIRVStripConvergenceIntrinsicsPass() {
return new SPIRVStripConvergentIntrinsics();
}