[Dy2Stat] Fix undefined var used in For

[Aurelius84]

PR types

Bug fixes

PR changes

Others

Describe

What's New?

Fix undefind var used in For

The reason is if a var is created only in if branch, and is not recognized by parse_cond_return.

• gast.Param should be considered as a kind of load semantic.

A Bug Example

from paddle.jit import to_static

def case_func(training):
    if training:
        targets = [1,2,3]
        targets_list = [targets]

    num_step = 3
    for i in range(num_step):
        if i > 0:
            rois, rosi_num = 1, 2
            if training:
                ros, rosi_num, targets = -1, -2, [-1,-2, -3]
                targets_list.append(targets)
    
    return rosi_num

to_static(case_func(False))

Transformed code is :

def case_func(training):

    def true_fn_0():
        targets = [1, 2, 3]
        targets_list = [targets]
        return

    def false_fn_0():
        return
    paddle.jit.dy2static.convert_ifelse(training, true_fn_0, false_fn_0, (),  <----- targets is not visible here.
        (), ())
    targets = None
    num_step = 3
    rosi_num = paddle.jit.dy2static.data_layer_not_check(name='rosi_num',
        shape=[-1], dtype='float32')
    i = 0

    def for_loop_condition_0(num_step, i, targets, rosi_num):
        return i < num_step

    def for_loop_body_0(num_step, i, targets, rosi_num):

        def true_fn_2(rosi_num, targets, training):
            rois = 1
            rosi_num = 2

            def true_fn_1(rosi_num, targets):
                y = targets
                ros = -1
                rosi_num = -2
                targets = [-1, -2, -3]
                paddle.jit.dy2static.convert_call(targets_list.append)(targets)
                return rosi_num, targets

            def false_fn_1(rosi_num, targets):
                return rosi_num, targets
            rosi_num, targets = paddle.jit.dy2static.convert_ifelse(training,
                true_fn_1, false_fn_1, (rosi_num, targets), (rosi_num,
                targets), (rosi_num, targets))
            return rosi_num, targets

        def false_fn_2(rosi_num, targets):
            return rosi_num, targets
        rosi_num, targets = paddle.jit.dy2static.convert_ifelse(i > 0,
            true_fn_2, false_fn_2, (rosi_num, targets, training), (rosi_num,
            targets), (rosi_num, targets))                              <----- targets is undefined
        i += 1
        return num_step, i, targets, rosi_num
    [num_step, i, targets, rosi_num] = paddle.jit.dy2static.convert_while_loop(
        for_loop_condition_0, for_loop_body_0, [num_step, i, targets, rosi_num]
        )
    return rosi_num

[paddle-bot-old]

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[liym27]

LGTM