1 //===-- NVPTXAtomicLower.cpp - Lower atomics of local memory ----*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 //  Lower atomics of local memory to simple load/stores
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "NVPTXAtomicLower.h"
14 #include "llvm/CodeGen/StackProtector.h"
15 #include "llvm/IR/Constants.h"
16 #include "llvm/IR/Function.h"
17 #include "llvm/IR/IRBuilder.h"
18 #include "llvm/IR/InstIterator.h"
19 #include "llvm/IR/Instructions.h"
20 #include "llvm/Transforms/Utils/LowerAtomic.h"
21 
22 #include "MCTargetDesc/NVPTXBaseInfo.h"
23 using namespace llvm;
24 
25 namespace {
26 // Hoisting the alloca instructions in the non-entry blocks to the entry
27 // block.
28 class NVPTXAtomicLower : public FunctionPass {
29 public:
30   static char ID; // Pass ID
31   NVPTXAtomicLower() : FunctionPass(ID) {}
32 
33   void getAnalysisUsage(AnalysisUsage &AU) const override {
34     AU.setPreservesCFG();
35   }
36 
37   StringRef getPassName() const override {
38     return "NVPTX lower atomics of local memory";
39   }
40 
41   bool runOnFunction(Function &F) override;
42 };
43 } // namespace
44 
45 bool NVPTXAtomicLower::runOnFunction(Function &F) {
46   SmallVector<AtomicRMWInst *> LocalMemoryAtomics;
47   for (Instruction &I : instructions(F))
48     if (AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(&I))
49       if (RMWI->getPointerAddressSpace() == ADDRESS_SPACE_LOCAL)
50         LocalMemoryAtomics.push_back(RMWI);
51 
52   bool Changed = false;
53   for (AtomicRMWInst *RMWI : LocalMemoryAtomics)
54     Changed |= lowerAtomicRMWInst(RMWI);
55   return Changed;
56 }
57 
58 char NVPTXAtomicLower::ID = 0;
59 
60 namespace llvm {
61 void initializeNVPTXAtomicLowerPass(PassRegistry &);
62 }
63 
64 INITIALIZE_PASS(NVPTXAtomicLower, "nvptx-atomic-lower",
65                 "Lower atomics of local memory to simple load/stores", false,
66                 false)
67 
68 FunctionPass *llvm::createNVPTXAtomicLowerPass() {
69   return new NVPTXAtomicLower();
70 }
71