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TPREFETCH

Tile Operation Diagram

TPREFETCH tile operation

Introduction

Prefetch data from global memory into a tile-local cache/buffer (implementation-defined). This is typically used to reduce latency before a subsequent TLOAD.

Note: unlike most PTO instructions, TPREFETCH does not implicitly call TSYNC(events...) in the C++ wrapper.

Assembly Syntax

Synchronous form:

%dst = tprefetch %src : !pto.global<...> -> !pto.tile<...>

AS Level 1 (SSA)

%dst = pto.tprefetch %src : !pto.global<...> -> !pto.tile<...>

AS Level 2 (DPS)

pto.tprefetch ins(%src : !pto.global<...>) outs(%dst : !pto.tile_buf<...>)

C++ Intrinsic

Declared in include/pto/common/pto_instr.hpp:

template <typename TileData, typename GlobalData>
PTO_INST RecordEvent TPREFETCH(TileData &dst, GlobalData &src);

Constraints

Semantics and caching behavior are target/implementation-defined.
Some targets may ignore prefetches or treat them as hints.

Math Interpretation

Unless otherwise specified, semantics are defined over the valid region and target-dependent behavior is marked as implementation-defined.

Examples

See related examples in docs/isa/ and docs/coding/tutorials/.

ASM Form Examples

Auto Mode

# Auto mode: compiler/runtime-managed placement and scheduling.
%dst = pto.tprefetch %src : !pto.global<...> -> !pto.tile<...>

Manual Mode

# Manual mode: resources must be bound explicitly before issuing the instruction.
# Optional for tile operands:
# pto.tassign %arg0, @tile(0x1000)
# pto.tassign %arg1, @tile(0x2000)
%dst = pto.tprefetch %src : !pto.global<...> -> !pto.tile<...>

PTO Assembly Form

%dst = tprefetch %src : !pto.global<...> -> !pto.tile<...>
# AS Level 2 (DPS)
pto.tprefetch ins(%src : !pto.global<...>) outs(%dst : !pto.tile_buf<...>)