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merge multiple equal terminals into one

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This commit is contained in:
Oliver Schneider 2016-03-23 14:50:08 +01:00
parent 25ed62ff23
commit 5911ccaba8
1 changed files with 21 additions and 8 deletions
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29
src/booleans.rs
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@ -34,10 +34,13 @@ impl LateLintPass for NonminimalBool {
struct NonminimalBoolVisitor<'a, 'tcx: 'a>(&'a LateContext<'a, 'tcx>);
use quine_mc_cluskey::Bool;
struct Hir2Qmm<'tcx>(Vec<&'tcx Expr>);
struct Hir2Qmm<'a, 'tcx: 'a, 'v> {
terminals: Vec<&'v Expr>,
cx: &'a LateContext<'a, 'tcx>
}
impl<'tcx> Hir2Qmm<'tcx> {
fn extract(&mut self, op: BinOp_, a: &[&'tcx Expr], mut v: Vec<Bool>) -> Result<Vec<Bool>, String> {
impl<'a, 'tcx, 'v> Hir2Qmm<'a, 'tcx, 'v> {
fn extract(&mut self, op: BinOp_, a: &[&'v Expr], mut v: Vec<Bool>) -> Result<Vec<Bool>, String> {
for a in a {
if let ExprBinary(binop, ref lhs, ref rhs) = a.node {
if binop.node == op {
@ -50,7 +53,7 @@ impl<'tcx> Hir2Qmm<'tcx> {
Ok(v)
}
fn run(&mut self, e: &'tcx Expr) -> Result<Bool, String> {
fn run(&mut self, e: &'v Expr) -> Result<Bool, String> {
match e.node {
ExprUnary(UnNot, ref inner) => return Ok(Bool::Not(box self.run(inner)?)),
ExprBinary(binop, ref lhs, ref rhs) => {
@ -69,8 +72,15 @@ impl<'tcx> Hir2Qmm<'tcx> {
},
_ => {},
}
let n = self.0.len();
self.0.push(e);
if let Some((n, _)) = self.terminals
.iter()
.enumerate()
.find(|&(_, expr)| SpanlessEq::new(self.cx).ignore_fn().eq_expr(e, expr)) {
#[allow(cast_possible_truncation)]
return Ok(Bool::Term(n as u8));
}
let n = self.terminals.len();
self.terminals.push(e);
if n < 32 {
#[allow(cast_possible_truncation)]
Ok(Bool::Term(n as u8))
@ -157,7 +167,10 @@ fn simple_negate(b: Bool) -> Bool {
impl<'a, 'tcx> NonminimalBoolVisitor<'a, 'tcx> {
fn bool_expr(&self, e: &Expr) {
let mut h2q = Hir2Qmm(Vec::new());
let mut h2q = Hir2Qmm {
terminals: Vec::new(),
cx: self.0,
};
if let Ok(expr) = h2q.run(e) {
let mut simplified = expr.simplify();
for simple in Bool::Not(Box::new(expr.clone())).simplify() {
@ -170,7 +183,7 @@ impl<'a, 'tcx> NonminimalBoolVisitor<'a, 'tcx> {
if !simplified.iter().any(|s| *s == expr) {
span_lint_and_then(self.0, NONMINIMAL_BOOL, e.span, "this boolean expression can be simplified", |db| {
for suggestion in &simplified {
db.span_suggestion(e.span, "try", suggest(self.0, suggestion, &h2q.0));
db.span_suggestion(e.span, "try", suggest(self.0, suggestion, &h2q.terminals));
}
});
}