1//===- HexagonRemoveExtendArgs.cpp - Remove unnecessary argument sign extends //
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Pass that removes sign extends for function parameters. These parameters
11// are already sign extended by the caller per Hexagon's ABI
12//
13//===----------------------------------------------------------------------===//
14
15#include "HexagonTargetMachine.h"
16#include "llvm/Function.h"
17#include "llvm/Instructions.h"
18#include "llvm/Pass.h"
19#include "llvm/CodeGen/MachineFunctionAnalysis.h"
20#include "llvm/Transforms/Scalar.h"
21
22using namespace llvm;
23namespace {
24  struct HexagonRemoveExtendArgs : public FunctionPass {
25  public:
26    static char ID;
27    HexagonRemoveExtendArgs() : FunctionPass(ID) {}
28    virtual bool runOnFunction(Function &F);
29
30    const char *getPassName() const {
31      return "Remove sign extends";
32    }
33
34    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
35      AU.addRequired<MachineFunctionAnalysis>();
36      AU.addPreserved<MachineFunctionAnalysis>();
37      FunctionPass::getAnalysisUsage(AU);
38    }
39  };
40}
41
42char HexagonRemoveExtendArgs::ID = 0;
43RegisterPass<HexagonRemoveExtendArgs> X("reargs",
44                                        "Remove Sign and Zero Extends for Args"
45                                        );
46
47
48
49bool HexagonRemoveExtendArgs::runOnFunction(Function &F) {
50  unsigned Idx = 1;
51  for (Function::arg_iterator AI = F.arg_begin(), AE = F.arg_end(); AI != AE;
52       ++AI, ++Idx) {
53    if (F.paramHasAttr(Idx, Attribute::SExt)) {
54      Argument* Arg = AI;
55      if (!isa<PointerType>(Arg->getType())) {
56        for (Instruction::use_iterator UI = Arg->use_begin();
57             UI != Arg->use_end();) {
58          if (isa<SExtInst>(*UI)) {
59            Instruction* Use = cast<Instruction>(*UI);
60            SExtInst* SI = new SExtInst(Arg, Use->getType());
61            assert (EVT::getEVT(SI->getType()) ==
62                    (EVT::getEVT(Use->getType())));
63            ++UI;
64            Use->replaceAllUsesWith(SI);
65            Instruction* First = F.getEntryBlock().begin();
66            SI->insertBefore(First);
67            Use->eraseFromParent();
68          } else {
69            ++UI;
70          }
71        }
72      }
73    }
74  }
75  return true;
76}
77
78
79
80FunctionPass *llvm::createHexagonRemoveExtendOps(HexagonTargetMachine &TM) {
81  return new HexagonRemoveExtendArgs();
82}
83