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add pass_move_add_to

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This commit is contained in:
nora 2022-04-16 14:35:56 +02:00
parent 014770b6fe
commit 93f97e9a08
4 changed files with 95 additions and 25 deletions
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72
rust2/src/opts.rs
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@ -40,10 +40,20 @@ impl Debug for Stmt<'_> {
#[derive(Debug, Clone)]
pub enum StmtKind<'ir> {
Add(u8),
Sub(u8),
AddOffset(i32, u8),
SubOffset(i32, u8),
Add(u8), // todo: we probably want to remove this
Sub(u8), // todo: we probably want to remove this
AddOffset {
offset: i32,
n: u8,
},
SubOffset {
offset: i32,
n: u8,
},
/// Sets the current cell to 0 and adds that value of the cell to another cell at `offset`
MoveAddTo {
offset: i32,
},
Right(usize),
Left(usize),
Loop(Ir<'ir>),
@ -59,6 +69,7 @@ pub fn optimize<'ir>(alloc: &'ir Bump, instrs: &[(Instr<'_>, Span)]) -> Ir<'ir>
pass_set_n(&mut ir);
pass_cancel_left_right_add_sub(&mut ir);
pass_add_sub_offset(&mut ir);
pass_move_add_to(&mut ir);
ir
}
@ -219,22 +230,67 @@ fn pass_add_sub_offset(ir: &mut Ir<'_>) {
window_pass(ir, pass_add_sub_offset, |[a, b, c]| {
match (a.kind(), b.kind(), c.kind()) {
(StmtKind::Right(r), StmtKind::Add(n), StmtKind::Left(l)) if r == l => {
WindowPassAction::Merge(StmtKind::AddOffset(i32::try_from(*r).unwrap(), *n))
WindowPassAction::Merge(StmtKind::AddOffset {
offset: i32::try_from(*r).unwrap(),
n: *n,
})
}
(StmtKind::Left(l), StmtKind::Add(n), StmtKind::Right(r)) if r == l => {
WindowPassAction::Merge(StmtKind::AddOffset(-i32::try_from(*r).unwrap(), *n))
WindowPassAction::Merge(StmtKind::AddOffset {
offset: -i32::try_from(*r).unwrap(),
n: *n,
})
}
(StmtKind::Right(r), StmtKind::Sub(n), StmtKind::Left(l)) if r == l => {
WindowPassAction::Merge(StmtKind::SubOffset(i32::try_from(*r).unwrap(), *n))
WindowPassAction::Merge(StmtKind::SubOffset {
offset: i32::try_from(*r).unwrap(),
n: *n,
})
}
(StmtKind::Left(l), StmtKind::Sub(n), StmtKind::Right(r)) if r == l => {
WindowPassAction::Merge(StmtKind::SubOffset(-i32::try_from(*r).unwrap(), *n))
WindowPassAction::Merge(StmtKind::SubOffset {
offset: -i32::try_from(*r).unwrap(),
n: *n,
})
}
_ => WindowPassAction::None,
}
})
}
/// pass that replaces `Loop([Sub(1) AddOffset(o, 1)])` with `MoveAddTo(o)`
#[tracing::instrument]
fn pass_move_add_to(ir: &mut Ir<'_>) {
for stmt in &mut ir.stmts {
if let Stmt {
kind: StmtKind::Loop(body),
span,
} = stmt
{
if let [Stmt {
kind: StmtKind::Sub(1),
..
}, Stmt {
kind: StmtKind::AddOffset { offset, n: 1 },
..
}]
| [Stmt {
kind: StmtKind::AddOffset { offset, n: 1 },
..
}, Stmt {
kind: StmtKind::Sub(1),
..
}] = body.stmts.as_slice()
{
trace!(?span, ?offset, "Replacing Statement with MoveAddTo");
*stmt = Stmt::new(StmtKind::MoveAddTo { offset: *offset }, *span);
} else {
pass_move_add_to(body);
}
}
}
}
enum WindowPassAction<'ir> {
None,
Merge(StmtKind<'ir>),