contrib/llvm/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/Intrinsics.h"
  19 #include "llvm/IR/Instructions.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   LLVMContext &Context = C->getParent()->getContext();
  69   IntegerType *Int32Ty = Type::getInt32Ty(Context);
  70   Metadata *LowAndHigh[] = {
  71       ConstantAsMetadata::get(ConstantInt::get(Int32Ty, Low)),
  72       ConstantAsMetadata::get(ConstantInt::get(Int32Ty, High))};
  73   C->setMetadata(LLVMContext::MD_range, MDNode::get(Context, LowAndHigh));
  74   return true;
  75 }
  76
  77 bool NVVMIntrRange::runOnFunction(Function &F) {
  78   // Go through the calls in this function.
  79   bool Changed = false;
  80   for (Instruction &I : instructions(F)) {
  81     CallInst *Call = dyn_cast<CallInst>(&I);
  82     if (!Call)
  83       continue;
  84
  85     if (Function *Callee = Call->getCalledFunction()) {
  86       switch (Callee->getIntrinsicID()) {
  87       // Index within block
  88       case Intrinsic::nvvm_read_ptx_sreg_tid_x:
  89         Changed |= addRangeMetadata(0, MaxBlockSize.x, Call);
  90         break;
  91       case Intrinsic::nvvm_read_ptx_sreg_tid_y:
  92         Changed |= addRangeMetadata(0, MaxBlockSize.y, Call);
  93         break;
  94       case Intrinsic::nvvm_read_ptx_sreg_tid_z:
  95         Changed |= addRangeMetadata(0, MaxBlockSize.z, Call);
  96         break;
  97
  98       // Block size
  99       case Intrinsic::nvvm_read_ptx_sreg_ntid_x:
 100         Changed |= addRangeMetadata(1, MaxBlockSize.x+1, Call);
 101         break;
 102       case Intrinsic::nvvm_read_ptx_sreg_ntid_y:
 103         Changed |= addRangeMetadata(1, MaxBlockSize.y+1, Call);
 104         break;
 105       case Intrinsic::nvvm_read_ptx_sreg_ntid_z:
 106         Changed |= addRangeMetadata(1, MaxBlockSize.z+1, Call);
 107         break;
 108
 109       // Index within grid
 110       case Intrinsic::nvvm_read_ptx_sreg_ctaid_x:
 111         Changed |= addRangeMetadata(0, MaxGridSize.x, Call);
 112         break;
 113       case Intrinsic::nvvm_read_ptx_sreg_ctaid_y:
 114         Changed |= addRangeMetadata(0, MaxGridSize.y, Call);
 115         break;
 116       case Intrinsic::nvvm_read_ptx_sreg_ctaid_z:
 117         Changed |= addRangeMetadata(0, MaxGridSize.z, Call);
 118         break;
 119
 120       // Grid size
 121       case Intrinsic::nvvm_read_ptx_sreg_nctaid_x:
 122         Changed |= addRangeMetadata(1, MaxGridSize.x+1, Call);
 123         break;
 124       case Intrinsic::nvvm_read_ptx_sreg_nctaid_y:
 125         Changed |= addRangeMetadata(1, MaxGridSize.y+1, Call);
 126         break;
 127       case Intrinsic::nvvm_read_ptx_sreg_nctaid_z:
 128         Changed |= addRangeMetadata(1, MaxGridSize.z+1, Call);
 129         break;
 130
 131       // warp size is constant 32.
 132       case Intrinsic::nvvm_read_ptx_sreg_warpsize:
 133         Changed |= addRangeMetadata(32, 32+1, Call);
 134         break;
 135
 136       // Lane ID is [0..warpsize)
 137       case Intrinsic::nvvm_read_ptx_sreg_laneid:
 138         Changed |= addRangeMetadata(0, 32, Call);
 139         break;
 140
 141       default:
 142         break;
 143       }
 144     }
 145   }
 146
 147   return Changed;
 148 }