source: icGREP/icgrep-devel/icgrep/kernels/deletion.cpp @ 5202

Last change on this file since 5202 was 5202, checked in by nmedfort, 2 years ago

Initial work on adding types to PabloAST and mutable Var objects.

File size: 5.6 KB
Line 
1/*
2 *  Copyright (c) 2016 International Characters.
3 *  This software is licensed to the public under the Open Software License 3.0.
4 */
5
6#include <kernels/kernel.h>
7#include <kernels/deletion.h>
8#include <IDISA/idisa_builder.h>
9#include <llvm/IR/Value.h>
10
11std::vector<Value *> parallel_prefix_deletion_masks(IDISA::IDISA_Builder * iBuilder, unsigned fw, Value * del_mask) {
12    Value * m = iBuilder->simd_not(del_mask);
13    Value * mk = iBuilder->simd_slli(fw, del_mask, 1);
14    std::vector<Value *> move_masks;
15    for (unsigned shift = 1; shift < fw; shift *= 2) {
16        Value * mp = mk;
17        for (unsigned lookright = 1; lookright < fw; lookright *= 2) {
18            mp = iBuilder->simd_xor(mp, iBuilder->simd_slli(fw, mp, lookright));
19        }
20        Value * mv = iBuilder->simd_and(mp, m);
21        m = iBuilder->simd_or(iBuilder->simd_xor(m, mv), iBuilder->simd_srli(fw, mv, shift));
22        mk = iBuilder->simd_and(mk, iBuilder->simd_not(mp));
23        move_masks.push_back(mv);
24    }
25    return move_masks;
26}
27
28Value * apply_parallel_prefix_deletion(IDISA::IDISA_Builder * iBuilder, unsigned fw, Value * del_mask, std::vector<Value *> mv, Value * strm) {
29    Value * s = iBuilder->simd_and(strm, iBuilder->simd_not(del_mask));
30    for (unsigned i = 0; i < mv.size(); i++) {
31        unsigned shift = 1 << i;
32        Value * t = iBuilder->simd_and(s, mv[i]);
33        s = iBuilder->simd_or(iBuilder->simd_xor(s, t), iBuilder->simd_srli(fw, t, shift));
34    }
35    return s;
36}
37
38Value * partial_sum_popcount(IDISA::IDISA_Builder * iBuilder, unsigned fw, Value * mask) {
39    Value * per_field = iBuilder->simd_popcount(fw, mask);
40    for (unsigned move = 1; move < iBuilder->getBitBlockWidth()/fw; move *= 2) {
41        per_field = iBuilder->simd_add(fw, per_field, iBuilder->mvmd_slli(fw, per_field, move));
42    }
43    return per_field;
44}
45
46// Apply deletion to a set of stream_count input streams to produce a set of output streams.
47// Kernel inputs: stream_count data streams plus one del_mask stream
48// Outputs: the deleted streams, plus a partial sum popcount
49
50namespace kernel {
51
52void DeletionKernel::generateDoBlockMethod() {
53    auto savePoint = iBuilder->saveIP();
54    Module * m = iBuilder->getModule();
55   
56    Function * doBlockFunction = m->getFunction(mKernelName + doBlock_suffix);
57   
58    iBuilder->SetInsertPoint(BasicBlock::Create(iBuilder->getContext(), "entry", doBlockFunction, 0));
59   
60    Value * self = getParameter(doBlockFunction, "self");
61    Value * blockNo = getScalarField(self, blockNoScalar);
62    Value * inputStreamBlock = getStreamSetBlockPtr(self, "inputStreamSet", blockNo);
63    Value * outputStreamBlock = getStreamSetBlockPtr(self, "outputStreamSet", blockNo);
64    Value * delCountBlock = getStreamSetBlockPtr(self, "deletionCounts", blockNo);
65
66    Value * del_mask = iBuilder->CreateBlockAlignedLoad(inputStreamBlock, {iBuilder->getInt32(0), iBuilder->getInt32(mStreamCount)});
67   
68    std::vector<Value *> move_masks = parallel_prefix_deletion_masks(iBuilder, mDeletionFieldWidth, del_mask);
69   
70    for (unsigned j = 0; j < mStreamCount; ++j) {
71        Value * input = iBuilder->CreateBlockAlignedLoad(inputStreamBlock, {iBuilder->getInt32(0), iBuilder->getInt32(j)});
72        Value * output = apply_parallel_prefix_deletion(iBuilder, mDeletionFieldWidth, del_mask, move_masks, input);
73        iBuilder->CreateBlockAlignedStore(output, outputStreamBlock, {iBuilder->getInt32(0), iBuilder->getInt32(j)});
74    }
75    Value * counts = partial_sum_popcount(iBuilder, mDeletionFieldWidth, iBuilder->simd_not(del_mask));
76    iBuilder->CreateBlockAlignedStore(iBuilder->bitCast(counts), delCountBlock, {iBuilder->getInt32(0), iBuilder->getInt32(0)});
77    /* Stream deletion has only been applied within fields; the actual number of data items
78     * has not yet changed.   */
79    Value * produced = getProducedItemCount(self);
80    produced = iBuilder->CreateAdd(produced, ConstantInt::get(iBuilder->getSizeTy(), iBuilder->getStride()));
81    setProducedItemCount(self, produced);   
82    iBuilder->CreateRetVoid();
83    iBuilder->restoreIP(savePoint);
84}
85
86void DeletionKernel::generateFinalBlockMethod() {
87    auto savePoint = iBuilder->saveIP();
88    Module * m = iBuilder->getModule();
89   
90    unsigned blockSize = iBuilder->getBitBlockWidth();
91    Function * doBlockFunction = m->getFunction(mKernelName + doBlock_suffix);
92    Function * finalBlockFunction = m->getFunction(mKernelName + finalBlock_suffix);
93
94    iBuilder->SetInsertPoint(BasicBlock::Create(iBuilder->getContext(), "entry", finalBlockFunction, 0));
95    Value * remainingBytes = getParameter(finalBlockFunction, "remainingBytes");
96    Value * self = getParameter(finalBlockFunction, "self");
97    Value * blockNo = getScalarField(self, blockNoScalar);
98    Value * inputStreamBlock = getStreamSetBlockPtr(self, "inputStreamSet", blockNo);
99    Value * remaining = iBuilder->CreateZExt(remainingBytes, iBuilder->getIntNTy(blockSize));
100    Value * EOF_del = iBuilder->bitCast(iBuilder->CreateShl(Constant::getAllOnesValue(iBuilder->getIntNTy(blockSize)), remaining));
101    Value * const delmaskPtr = iBuilder->CreateGEP(inputStreamBlock, {iBuilder->getInt32(0), iBuilder->getInt32(16)});
102    Value * const delmaskVal = iBuilder->CreateBlockAlignedLoad(delmaskPtr);
103    iBuilder->CreateBlockAlignedStore(iBuilder->CreateOr(EOF_del, delmaskVal), delmaskPtr);
104    iBuilder->CreateCall(doBlockFunction, {self});
105    /* Adjust the produced item count */
106    Value * produced = getProducedItemCount(self);
107    produced = iBuilder->CreateSub(produced, ConstantInt::get(iBuilder->getSizeTy(), iBuilder->getStride()));
108    setProducedItemCount(self, iBuilder->CreateAdd(produced, remainingBytes));
109
110    iBuilder->CreateRetVoid();
111    iBuilder->restoreIP(savePoint);
112}
113
114}
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