Commit f10b9e8fd72aae33b127c18e3f8a64a4f56b1b69 | zig

author	Xavier Bouchoux <xavierb@gmail.com> 2023-06-24 10:47:20+00:00
committer	Andrew Kelley <andrew@ziglang.org> 2023-06-24 12:57:46-07:00
log	f10b9e8fd72aae33b127c18e3f8a64a4f56b1b69
tree	e677f852c23f7123282d184ddb67181097588619
parent	a5e15eced0e9cb00871966ede74eed9b3a07183c

update Liveness to detect that safety checks do not modify memory

followup to [25d3713b07a100d8fdb349317db97fd9d0c1e366]
Resolves #12215

Previous code didn't account for the extra unreach() that now exists in the air:

```
 %29!= block(void, {
    %30!= cond_br(%22!, {
      %31!= br(%29, @Air.Inst.Ref.void_value)
    }, {
      %2! %15!
      %27!= call(%26, [%19!, %21])
      %28!= unreach()
    })
  } %22!)
```

1 files changed, 9 insertions(+), 2 deletions(-)

src
- Liveness.zig

src/Liveness.zig+9-2

...	...	@@ -621,11 +621,18 @@ pub fn categorizeOperand(
621	621	if (inst_data.operand == operand_ref and operandDies(l, body[0], 0))
622	622	return .tomb;
623	623
624		if (cond_extra.data.then_body_len != 1 or cond_extra.data.else_body_len != 1)
	624	if (cond_extra.data.then_body_len > 2 or cond_extra.data.else_body_len > 2)
	625	return .complex;
	626
	627	const then_body = air.extra[cond_extra.end..][0..cond_extra.data.then_body_len];
	628	const else_body = air.extra[cond_extra.end + cond_extra.data.then_body_len ..][0 .. cond_extra.data.then_body_len + cond_extra.data.else_body_len];
	629	if (then_body.len > 1 and air_tags[then_body[1]] != .unreach)
	630	return .complex;
	631	if (else_body.len > 1 and air_tags[else_body[1]] != .unreach)
625	632	return .complex;
626	633
627	634	var operand_live: bool = true;
628		for (air.extra[cond_extra.end..][0..2]) \|cond_inst\| {
	635	for (&[_]u32{ then_body[0], else_body[0] }) \|cond_inst\| {
629	636	if (l.categorizeOperand(air, cond_inst, operand, ip) == .tomb)
630	637	operand_live = false;
631	638