From 802b645e81a72399a7ef47ef000d468c775dcd3e Mon Sep 17 00:00:00 2001 From: Mark Shannon Date: Tue, 2 Feb 2021 14:59:15 +0000 Subject: Only eliminate jumps to successor block if jump is unconditional. (GH-24417) * Prevents elimination of the sole test of a value in statements like: if x or True: ... --- Lib/test/test_bool.py | 16 ++++++++++++++++ Python/compile.c | 21 ++++----------------- 2 files changed, 20 insertions(+), 17 deletions(-) diff --git a/Lib/test/test_bool.py b/Lib/test/test_bool.py index 7b3a385..bec44d0 100644 --- a/Lib/test/test_bool.py +++ b/Lib/test/test_bool.py @@ -354,6 +354,22 @@ class BoolTest(unittest.TestCase): self.assertIs(type(False.real), int) self.assertIs(type(False.imag), int) + def test_bool_called_at_least_once(self): + class X: + def __init__(self): + self.count = 0 + def __bool__(self): + self.count += 1 + return True + + def f(x): + if x or True: + pass + + x = X() + f(x) + self.assertGreaterEqual(x.count, 1) + def test_main(): support.run_unittest(BoolTest) diff --git a/Python/compile.c b/Python/compile.c index 9927f5a..a0a257f 100644 --- a/Python/compile.c +++ b/Python/compile.c @@ -6586,27 +6586,14 @@ optimize_cfg(struct assembler *a, PyObject *consts) for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { if (b->b_iused > 0) { struct instr *b_last_instr = &b->b_instr[b->b_iused - 1]; - if (b_last_instr->i_opcode == POP_JUMP_IF_FALSE || - b_last_instr->i_opcode == POP_JUMP_IF_TRUE || - b_last_instr->i_opcode == JUMP_ABSOLUTE || + if (b_last_instr->i_opcode == JUMP_ABSOLUTE || b_last_instr->i_opcode == JUMP_FORWARD) { if (b_last_instr->i_target == b->b_next) { assert(b->b_next->b_iused); b->b_nofallthrough = 0; - switch(b_last_instr->i_opcode) { - case POP_JUMP_IF_FALSE: - case POP_JUMP_IF_TRUE: - b_last_instr->i_opcode = POP_TOP; - b_last_instr->i_target = NULL; - b_last_instr->i_oparg = 0; - break; - case JUMP_ABSOLUTE: - case JUMP_FORWARD: - b_last_instr->i_opcode = NOP; - clean_basic_block(b, -1); - maybe_empty_blocks = 1; - break; - } + b_last_instr->i_opcode = NOP; + clean_basic_block(b, -1); + maybe_empty_blocks = 1; } } } -- cgit v0.12