lib/Target/NVPTX/NVVMIntrRange.cpp

   1 //===- NVVMIntrRange.cpp - Set !range metadata for NVVM intrinsics --------===//
   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 // This pass adds appropriate !range metadata for calls to NVVM
  11 // intrinsics that return a limited range of values.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "NVPTX.h"
  16 #include "llvm/IR/Constants.h"
  17 #include "llvm/IR/InstIterator.h"
  18 #include "llvm/IR/Instructions.h"
  19 #include "llvm/IR/Intrinsics.h"
  20
  21 using namespace llvm;
  22
  23 #define DEBUG_TYPE "nvvm-intr-range"
  24
  25 namespace llvm { void initializeNVVMIntrRangePass(PassRegistry &); }
  26
  27 // Add !range metadata based on limits of given SM variant.
  28 static cl::opt<unsigned> NVVMIntrRangeSM("nvvm-intr-range-sm", cl::init(20),
  29                                          cl::Hidden, cl::desc("SM variant"));
  30
  31 namespace {
  32 class NVVMIntrRange : public FunctionPass {
  33  private:
  34    struct {
  35      unsigned x, y, z;
  36    } MaxBlockSize, MaxGridSize;
  37
  38  public:
  39    static char ID;
  40    NVVMIntrRange() : NVVMIntrRange(NVVMIntrRangeSM) {}
  41    NVVMIntrRange(unsigned int SmVersion) : FunctionPass(ID) {
  42      MaxBlockSize.x = 1024;
  43      MaxBlockSize.y = 1024;
  44      MaxBlockSize.z = 64;
  45
  46      MaxGridSize.x = SmVersion >= 30 ? 0x7fffffff : 0xffff;
  47      MaxGridSize.y = 0xffff;
  48      MaxGridSize.z = 0xffff;
  49
  50      initializeNVVMIntrRangePass(*PassRegistry::getPassRegistry());
  51    }
  52
  53    bool runOnFunction(Function &) override;
  54 };
  55 }
  56
  57 FunctionPass *llvm::createNVVMIntrRangePass(unsigned int SmVersion) {
  58   return new NVVMIntrRange(SmVersion);
  59 }
  60
  61 char NVVMIntrRange::ID = 0;
  62 INITIALIZE_PASS(NVVMIntrRange, "nvvm-intr-range",
  63                 "Add !range metadata to NVVM intrinsics.", false, false)
  64
  65 // Adds the passed-in [Low,High) range information as metadata to the
  66 // passed-in call instruction.
  67 static bool addRangeMetadata(uint64_t Low, uint64_t High, CallInst *C) {
  68   // This call already has range metadata, nothing to do.
  69   if (C->getMetadata(LLVMContext::MD_range))
  70     return false;
  71
  72   LLVMContext &Context = C->getParent()->getContext();
  73   IntegerType *Int32Ty = Type::getInt32Ty(Context);
  74   Metadata *LowAndHigh[] = {
  75       ConstantAsMetadata::get(ConstantInt::get(Int32Ty, Low)),
  76       ConstantAsMetadata::get(ConstantInt::get(Int32Ty, High))};
  77   C->setMetadata(LLVMContext::MD_range, MDNode::get(Context, LowAndHigh));
  78   return true;
  79 }
  80
  81 bool NVVMIntrRange::runOnFunction(Function &F) {
  82   // Go through the calls in this function.
  83   bool Changed = false;
  84   for (Instruction &I : instructions(F)) {
  85     CallInst *Call = dyn_cast<CallInst>(&I);
  86     if (!Call)
  87       continue;
  88
  89     if (Function *Callee = Call->getCalledFunction()) {
  90       switch (Callee->getIntrinsicID()) {
  91       // Index within block
  92       case Intrinsic::nvvm_read_ptx_sreg_tid_x:
  93         Changed |= addRangeMetadata(0, MaxBlockSize.x, Call);
  94         break;
  95       case Intrinsic::nvvm_read_ptx_sreg_tid_y:
  96         Changed |= addRangeMetadata(0, MaxBlockSize.y, Call);
  97         break;
  98       case Intrinsic::nvvm_read_ptx_sreg_tid_z:
  99         Changed |= addRangeMetadata(0, MaxBlockSize.z, Call);
 100         break;
 101
 102       // Block size
 103       case Intrinsic::nvvm_read_ptx_sreg_ntid_x:
 104         Changed |= addRangeMetadata(1, MaxBlockSize.x+1, Call);
 105         break;
 106       case Intrinsic::nvvm_read_ptx_sreg_ntid_y:
 107         Changed |= addRangeMetadata(1, MaxBlockSize.y+1, Call);
 108         break;
 109       case Intrinsic::nvvm_read_ptx_sreg_ntid_z:
 110         Changed |= addRangeMetadata(1, MaxBlockSize.z+1, Call);
 111         break;
 112
 113       // Index within grid
 114       case Intrinsic::nvvm_read_ptx_sreg_ctaid_x:
 115         Changed |= addRangeMetadata(0, MaxGridSize.x, Call);
 116         break;
 117       case Intrinsic::nvvm_read_ptx_sreg_ctaid_y:
 118         Changed |= addRangeMetadata(0, MaxGridSize.y, Call);
 119         break;
 120       case Intrinsic::nvvm_read_ptx_sreg_ctaid_z:
 121         Changed |= addRangeMetadata(0, MaxGridSize.z, Call);
 122         break;
 123
 124       // Grid size
 125       case Intrinsic::nvvm_read_ptx_sreg_nctaid_x:
 126         Changed |= addRangeMetadata(1, MaxGridSize.x+1, Call);
 127         break;
 128       case Intrinsic::nvvm_read_ptx_sreg_nctaid_y:
 129         Changed |= addRangeMetadata(1, MaxGridSize.y+1, Call);
 130         break;
 131       case Intrinsic::nvvm_read_ptx_sreg_nctaid_z:
 132         Changed |= addRangeMetadata(1, MaxGridSize.z+1, Call);
 133         break;
 134
 135       // warp size is constant 32.
 136       case Intrinsic::nvvm_read_ptx_sreg_warpsize:
 137         Changed |= addRangeMetadata(32, 32+1, Call);
 138         break;
 139
 140       // Lane ID is [0..warpsize)
 141       case Intrinsic::nvvm_read_ptx_sreg_laneid:
 142         Changed |= addRangeMetadata(0, 32, Call);
 143         break;
 144
 145       default:
 146         break;
 147       }
 148     }
 149   }
 150
 151   return Changed;
 152 }