LLVM  10.0.0svn
NVPTXAllocaHoisting.cpp
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1 //===-- AllocaHoisting.cpp - Hoist allocas to the entry block --*- 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 // Hoist the alloca instructions in the non-entry blocks to the entry blocks.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "NVPTXAllocaHoisting.h"
15 #include "llvm/IR/Constants.h"
16 #include "llvm/IR/Function.h"
17 #include "llvm/IR/Instructions.h"
18 using namespace llvm;
19 
20 namespace {
21 // Hoisting the alloca instructions in the non-entry blocks to the entry
22 // block.
23 class NVPTXAllocaHoisting : public FunctionPass {
24 public:
25  static char ID; // Pass ID
26  NVPTXAllocaHoisting() : FunctionPass(ID) {}
27 
28  void getAnalysisUsage(AnalysisUsage &AU) const override {
30  }
31 
32  StringRef getPassName() const override {
33  return "NVPTX specific alloca hoisting";
34  }
35 
36  bool runOnFunction(Function &function) override;
37 };
38 } // namespace
39 
41  bool functionModified = false;
42  Function::iterator I = function.begin();
43  Instruction *firstTerminatorInst = (I++)->getTerminator();
44 
45  for (Function::iterator E = function.end(); I != E; ++I) {
46  for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;) {
47  AllocaInst *allocaInst = dyn_cast<AllocaInst>(BI++);
48  if (allocaInst && isa<ConstantInt>(allocaInst->getArraySize())) {
49  allocaInst->moveBefore(firstTerminatorInst);
50  functionModified = true;
51  }
52  }
53  }
54 
55  return functionModified;
56 }
57 
59 
60 namespace llvm {
62 }
63 
65  NVPTXAllocaHoisting, "alloca-hoisting",
66  "Hoisting alloca instructions in non-entry blocks to the entry block",
67  false, false)
68 
69 FunctionPass *llvm::createAllocaHoisting() { return new NVPTXAllocaHoisting; }
const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:233
AnalysisUsage & addPreserved()
Add the specified Pass class to the set of analyses preserved by this pass.
This class represents lattice values for constants.
Definition: AllocatorList.h:23
FunctionPass * createAllocaHoisting()
static bool runOnFunction(Function &F, bool PostInlining)
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
This file contains the declarations for the subclasses of Constant, which represent the different fla...
Represent the analysis usage information of a pass.
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:284
void initializeNVPTXAllocaHoistingPass(PassRegistry &)
const Value * getArraySize() const
Get the number of elements allocated.
Definition: Instructions.h:92
Iterator for intrusive lists based on ilist_node.
INITIALIZE_PASS(NVPTXAllocaHoisting, "alloca-hoisting", "Hoisting alloca instructions in non-entry blocks to the entry block", false, false) FunctionPass *llvm
#define I(x, y, z)
Definition: MD5.cpp:58
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:332
void moveBefore(Instruction *MovePos)
Unlink this instruction from its current basic block and insert it into the basic block that MovePos ...
Definition: Instruction.cpp:86
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
PassRegistry - This class manages the registration and intitialization of the pass subsystem as appli...
Definition: PassRegistry.h:38
an instruction to allocate memory on the stack
Definition: Instructions.h:59