rewrite_gelu.cpp

/*
 * The MIT License (MIT)
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 * Copyright (c) 2015-2022 Advanced Micro Devices, Inc. All rights reserved.
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 * furnished to do so, subject to the following conditions:
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 * The above copyright notice and this permission notice shall be included in
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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#include <migraphx/rewrite_gelu.hpp>
#include <migraphx/make_op.hpp>
#include <migraphx/matcher.hpp>
#include <migraphx/match/gelu_erf.hpp>
#include <migraphx/common.hpp>

namespace migraphx {
inline namespace MIGRAPHX_INLINE_NS {

struct find_gelu_erf
{
    auto matcher() const { return match::gelu_erf(); }

    void apply(module& m, const match::matcher_result& r) const
    {
        auto ins = r.result;
        auto x   = r.instructions["x"];
        if(x->get_shape().type() != migraphx::shape::half_type)
            return;

        auto lit = m.add_literal(literal{shape{x->get_shape().type()}, {1.702f}});
        auto mul = insert_common_op(m, ins, make_op("mul"), {x, lit});
        auto sig = m.insert_instruction(ins, make_op("neg"), mul);
        sig      = m.insert_instruction(ins, make_op("exp"), sig);
        auto one = m.add_literal(literal{shape{x->get_shape().type()}, {1.0f}});
        sig      = insert_common_op(m, ins, make_op("add"), {sig, one});
        sig      = m.insert_instruction(ins, make_op("div"), x, sig);
        m.replace_instruction(ins, sig);
    }
};

void rewrite_gelu::apply(module& m) const { match::find_matches(m, find_gelu_erf{}); }

} // namespace MIGRAPHX_INLINE_NS
} // namespace migraphx