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//===- NVVMIntrRange.cpp - Set range attributes for NVVM intrinsics -------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This pass adds appropriate range attributes for calls to NVVM
// intrinsics that return a limited range of values.
//
//===----------------------------------------------------------------------===//
#include "NVPTX.h"
#include "NVPTXUtilities.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IntrinsicsNVPTX.h"
#include "llvm/IR/PassManager.h"
#include <cstdint>
using namespace llvm;
#define DEBUG_TYPE "nvvm-intr-range"
namespace {
class NVVMIntrRange : public FunctionPass {
public:
static char ID;
NVVMIntrRange() : FunctionPass(ID) {}
bool runOnFunction(Function &) override;
};
} // namespace
FunctionPass *llvm::createNVVMIntrRangePass() { return new NVVMIntrRange(); }
char NVVMIntrRange::ID = 0;
INITIALIZE_PASS(NVVMIntrRange, "nvvm-intr-range",
"Add !range metadata to NVVM intrinsics.", false, false)
// Adds the passed-in [Low,High) range information as metadata to the
// passed-in call instruction.
static bool addRangeAttr(uint64_t Low, uint64_t High, IntrinsicInst *II) {
if (II->getMetadata(LLVMContext::MD_range))
return false;
const uint64_t BitWidth = II->getType()->getIntegerBitWidth();
ConstantRange Range(APInt(BitWidth, Low), APInt(BitWidth, High));
if (auto CurrentRange = II->getRange())
Range = Range.intersectWith(CurrentRange.value());
II->addRangeRetAttr(Range);
return true;
}
static bool runNVVMIntrRange(Function &F) {
struct Vector3 {
unsigned X, Y, Z;
};
// All these annotations are only valid for kernel functions.
if (!isKernelFunction(F))
return false;
const auto OverallReqNTID = getOverallReqNTID(F);
const auto OverallMaxNTID = getOverallMaxNTID(F);
const auto OverallClusterRank = getOverallClusterRank(F);
// If this function lacks any range information, do nothing.
if (!(OverallReqNTID || OverallMaxNTID || OverallClusterRank))
return false;
const unsigned FunctionNTID = OverallReqNTID.value_or(
OverallMaxNTID.value_or(std::numeric_limits<unsigned>::max()));
const unsigned FunctionClusterRank =
OverallClusterRank.value_or(std::numeric_limits<unsigned>::max());
const Vector3 MaxBlockSize{std::min(1024u, FunctionNTID),
std::min(1024u, FunctionNTID),
std::min(64u, FunctionNTID)};
// We conservatively use the maximum grid size as an upper bound for the
// cluster rank.
const Vector3 MaxClusterRank{std::min(0x7fffffffu, FunctionClusterRank),
std::min(0xffffu, FunctionClusterRank),
std::min(0xffffu, FunctionClusterRank)};
const auto ProccessIntrinsic = [&](IntrinsicInst *II) -> bool {
switch (II->getIntrinsicID()) {
// Index within block
case Intrinsic::nvvm_read_ptx_sreg_tid_x:
return addRangeAttr(0, MaxBlockSize.X, II);
case Intrinsic::nvvm_read_ptx_sreg_tid_y:
return addRangeAttr(0, MaxBlockSize.Y, II);
case Intrinsic::nvvm_read_ptx_sreg_tid_z:
return addRangeAttr(0, MaxBlockSize.Z, II);
// Block size
case Intrinsic::nvvm_read_ptx_sreg_ntid_x:
return addRangeAttr(1, MaxBlockSize.X + 1, II);
case Intrinsic::nvvm_read_ptx_sreg_ntid_y:
return addRangeAttr(1, MaxBlockSize.Y + 1, II);
case Intrinsic::nvvm_read_ptx_sreg_ntid_z:
return addRangeAttr(1, MaxBlockSize.Z + 1, II);
// Cluster size
case Intrinsic::nvvm_read_ptx_sreg_cluster_ctaid_x:
return addRangeAttr(0, MaxClusterRank.X, II);
case Intrinsic::nvvm_read_ptx_sreg_cluster_ctaid_y:
return addRangeAttr(0, MaxClusterRank.Y, II);
case Intrinsic::nvvm_read_ptx_sreg_cluster_ctaid_z:
return addRangeAttr(0, MaxClusterRank.Z, II);
case Intrinsic::nvvm_read_ptx_sreg_cluster_nctaid_x:
return addRangeAttr(1, MaxClusterRank.X + 1, II);
case Intrinsic::nvvm_read_ptx_sreg_cluster_nctaid_y:
return addRangeAttr(1, MaxClusterRank.Y + 1, II);
case Intrinsic::nvvm_read_ptx_sreg_cluster_nctaid_z:
return addRangeAttr(1, MaxClusterRank.Z + 1, II);
case Intrinsic::nvvm_read_ptx_sreg_cluster_ctarank:
if (OverallClusterRank)
return addRangeAttr(0, FunctionClusterRank, II);
break;
case Intrinsic::nvvm_read_ptx_sreg_cluster_nctarank:
if (OverallClusterRank)
return addRangeAttr(1, FunctionClusterRank + 1, II);
break;
default:
return false;
}
return false;
};
// Go through the calls in this function.
bool Changed = false;
for (Instruction &I : instructions(F))
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I))
Changed |= ProccessIntrinsic(II);
return Changed;
}
bool NVVMIntrRange::runOnFunction(Function &F) { return runNVVMIntrRange(F); }
PreservedAnalyses NVVMIntrRangePass::run(Function &F,
FunctionAnalysisManager &AM) {
return runNVVMIntrRange(F) ? PreservedAnalyses::none()
: PreservedAnalyses::all();
}
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