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[Bug #19611] Remove never-reachable branch in logical expression

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This commit is contained in:
Nobuyoshi Nakada 2023-04-24 22:21:57 +09:00
parent b0cb54a378
commit c7bacf84f0
Notes: git 2023-04-27 05:52:43 +00:00 
Merged: https://github.com/ruby/ruby/pull/7754
2 changed files with 47 additions and 24 deletions
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61
compile.c
View File

@ -4252,6 +4252,37 @@ compile_flip_flop(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *const nod
return COMPILE_OK; return COMPILE_OK;
} }
static int
compile_branch_condition(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *cond,
LABEL *then_label, LABEL *else_label);
static int
compile_logical(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *cond,
LABEL *then_label, LABEL *else_label)
{
DECL_ANCHOR(seq);
INIT_ANCHOR(seq);
LABEL *label = NEW_LABEL(nd_line(cond));
if (!then_label) then_label = label;
else if (!else_label) else_label = label;
CHECK(compile_branch_condition(iseq, seq, cond, then_label, else_label));
if (LIST_INSN_SIZE_ONE(seq)) {
INSN *insn = (INSN *)ELEM_FIRST_INSN(FIRST_ELEMENT(seq));
if (insn->insn_id == BIN(jump) && (LABEL *)(insn->operands[0]) == label)
return COMPILE_OK;
}
if (!label->refcnt) {
ADD_INSN(seq, cond, putnil);
}
else {
ADD_LABEL(seq, label);
}
ADD_SEQ(ret, seq);
return COMPILE_OK;
}
static int static int
compile_branch_condition(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *cond, compile_branch_condition(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *cond,
LABEL *then_label, LABEL *else_label) LABEL *then_label, LABEL *else_label)
@ -4259,31 +4290,13 @@ compile_branch_condition(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *co
again: again:
switch (nd_type(cond)) { switch (nd_type(cond)) {
case NODE_AND: case NODE_AND:
{ CHECK(compile_logical(iseq, ret, cond->nd_1st, NULL, else_label));
LABEL *label = NEW_LABEL(nd_line(cond)); cond = cond->nd_2nd;
CHECK(compile_branch_condition(iseq, ret, cond->nd_1st, label, goto again;
else_label));
if (!label->refcnt) {
ADD_INSN(ret, cond, putnil);
break;
}
ADD_LABEL(ret, label);
cond = cond->nd_2nd;
goto again;
}
case NODE_OR: case NODE_OR:
{ CHECK(compile_logical(iseq, ret, cond->nd_1st, then_label, NULL));
LABEL *label = NEW_LABEL(nd_line(cond)); cond = cond->nd_2nd;
CHECK(compile_branch_condition(iseq, ret, cond->nd_1st, then_label, goto again;
label));
if (!label->refcnt) {
ADD_INSN(ret, cond, putnil);
break;
}
ADD_LABEL(ret, label);
cond = cond->nd_2nd;
goto again;
}
case NODE_LIT: /* NODE_LIT is always true */ case NODE_LIT: /* NODE_LIT is always true */
case NODE_TRUE: case NODE_TRUE:
case NODE_STR: case NODE_STR:

10
test/ruby/test_iseq.rb
View File

@ -759,4 +759,14 @@ class TestISeq < Test::Unit::TestCase
assert_equal :new, r.take assert_equal :new, r.take
RUBY RUBY
end end
def test_ever_condition_loop
assert_ruby_status([], "BEGIN {exit}; while true && true; end")
end
def test_unreachable_syntax_error
mesg = /Invalid break/
assert_syntax_error("false and break", mesg)
assert_syntax_error("if false and break; end", mesg)
end
end end