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gh-93678: apply remove_redundant_jumps in optimize_cfg (GH-96274)

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Irit Katriel 2022-09-01 11:03:52 +01:00 • committed by GitHub
parent e93d1bda77
commit 894cafd9a5
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2 changed files with 36 additions and 14 deletions
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6
Lib/test/test_peepholer.py
View file

@ -892,7 +892,8 @@ class DirectiCfgOptimizerTests(CfgOptimizationTestCase):
self.cfg_optimization_test(insts, expected, consts=list(range(5))) self.cfg_optimization_test(insts, expected, consts=list(range(5)))
def test_conditional_jump_forward_const_condition(self): def test_conditional_jump_forward_const_condition(self):
# The unreachable branch of the jump is removed # The unreachable branch of the jump is removed, the jump
# becomes redundant and is replaced by a NOP (for the lineno)
insts = [ insts = [
('LOAD_CONST', 3, 11), ('LOAD_CONST', 3, 11),
@ -903,8 +904,7 @@ class DirectiCfgOptimizerTests(CfgOptimizationTestCase):
] ]
expected = [ expected = [
('NOP', None, 11), ('NOP', None, 11),
('JUMP', lbl := self.Label(), 12), ('NOP', None, 12),
lbl,
('LOAD_CONST', '3', 14) ('LOAD_CONST', '3', 14)
] ]
self.cfg_optimization_test(insts, expected, consts=list(range(5))) self.cfg_optimization_test(insts, expected, consts=list(range(5)))

44
Python/compile.c
View file

@ -7396,6 +7396,9 @@ mark_cold(basicblock *entryblock) {
return 0; return 0;
} }
static int
remove_redundant_jumps(cfg_builder *g);
static int static int
push_cold_blocks_to_end(cfg_builder *g, int code_flags) { push_cold_blocks_to_end(cfg_builder *g, int code_flags) {
basicblock *entryblock = g->g_entryblock; basicblock *entryblock = g->g_entryblock;
@ -7465,6 +7468,12 @@ push_cold_blocks_to_end(cfg_builder *g, int code_flags) {
} }
assert(b != NULL && b->b_next == NULL); assert(b != NULL && b->b_next == NULL);
b->b_next = cold_blocks; b->b_next = cold_blocks;
if (cold_blocks != NULL) {
if (remove_redundant_jumps(g) < 0) {
return -1;
}
}
return 0; return 0;
} }
@ -8269,9 +8278,6 @@ trim_unused_consts(basicblock *entryblock, PyObject *consts);
static int static int
duplicate_exits_without_lineno(cfg_builder *g); duplicate_exits_without_lineno(cfg_builder *g);
static int
extend_block(basicblock *bb);
static int * static int *
build_cellfixedoffsets(struct compiler *c) build_cellfixedoffsets(struct compiler *c)
{ {
@ -8476,6 +8482,21 @@ propagate_line_numbers(basicblock *entryblock);
static void static void
eliminate_empty_basic_blocks(cfg_builder *g); eliminate_empty_basic_blocks(cfg_builder *g);
#ifndef NDEBUG
static bool
no_redundant_jumps(cfg_builder *g) {
for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) {
struct instr *last = basicblock_last_instr(b);
if (last != NULL) {
if (last->i_opcode == JUMP || last->i_opcode == JUMP_NO_INTERRUPT) {
assert(last->i_target != b->b_next);
return false;
}
}
}
return true;
}
#endif
static int static int
remove_redundant_jumps(cfg_builder *g) { remove_redundant_jumps(cfg_builder *g) {
@ -8592,8 +8613,8 @@ assemble(struct compiler *c, int addNone)
if (trim_unused_consts(g->g_entryblock, consts)) { if (trim_unused_consts(g->g_entryblock, consts)) {
goto error; goto error;
} }
if (duplicate_exits_without_lineno(g)) { if (duplicate_exits_without_lineno(g) < 0) {
return NULL; goto error;
} }
propagate_line_numbers(g->g_entryblock); propagate_line_numbers(g->g_entryblock);
guarantee_lineno_for_exits(g->g_entryblock, c->u->u_firstlineno); guarantee_lineno_for_exits(g->g_entryblock, c->u->u_firstlineno);
@ -8612,10 +8633,6 @@ assemble(struct compiler *c, int addNone)
if (push_cold_blocks_to_end(g, code_flags) < 0) { if (push_cold_blocks_to_end(g, code_flags) < 0) {
goto error; goto error;
} }
if (remove_redundant_jumps(g) < 0) {
goto error;
}
for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) { for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) {
clean_basic_block(b); clean_basic_block(b);
} }
@ -8627,6 +8644,8 @@ assemble(struct compiler *c, int addNone)
goto error; goto error;
} }
assert(no_redundant_jumps(g));
/* Can't modify the bytecode after computing jump offsets. */ /* Can't modify the bytecode after computing jump offsets. */
assemble_jump_offsets(g->g_entryblock); assemble_jump_offsets(g->g_entryblock);
@ -9488,7 +9507,7 @@ optimize_cfg(cfg_builder *g, PyObject *consts, PyObject *const_cache)
} }
} }
for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) { for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) {
if (extend_block(b)) { if (extend_block(b) < 0) {
return -1; return -1;
} }
} }
@ -9500,7 +9519,7 @@ optimize_cfg(cfg_builder *g, PyObject *consts, PyObject *const_cache)
assert(b->b_predecessors == 0); assert(b->b_predecessors == 0);
} }
for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) { for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) {
if (extend_block(b)) { if (extend_block(b) < 0) {
return -1; return -1;
} }
} }
@ -9517,6 +9536,9 @@ optimize_cfg(cfg_builder *g, PyObject *consts, PyObject *const_cache)
for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) { for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) {
clean_basic_block(b); clean_basic_block(b);
} }
if (remove_redundant_jumps(g) < 0) {
return -1;
}
return 0; return 0;
} }