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rustc_const_eval: work around double rounding.

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This commit is contained in:
Eduard Burtescu 2016-06-01 12:22:07 +03:00
parent 27673610a6
commit c77166c685
7 changed files with 291 additions and 101 deletions
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53
src/librustc/middle/const_val.rs
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@ -12,14 +12,12 @@ use syntax::parse::token::InternedString;
use syntax::ast;
use std::rc::Rc;
use hir::def_id::DefId;
use std::hash;
use std::mem::transmute;
use rustc_const_math::*;
use self::ConstVal::*;
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
#[derive(Clone, Debug, Hash, RustcEncodable, RustcDecodable, Eq, PartialEq)]
pub enum ConstVal {
Float(f64),
Float(ConstFloat),
Integral(ConstInt),
Str(InternedString),
ByteStr(Rc<Vec<u8>>),
@ -36,55 +34,10 @@ pub enum ConstVal {
Dummy,
}
impl hash::Hash for ConstVal {
fn hash<H: hash::Hasher>(&self, state: &mut H) {
match *self {
Float(a) => unsafe { transmute::<_,u64>(a) }.hash(state),
Integral(a) => a.hash(state),
Str(ref a) => a.hash(state),
ByteStr(ref a) => a.hash(state),
Bool(a) => a.hash(state),
Struct(a) => a.hash(state),
Tuple(a) => a.hash(state),
Function(a) => a.hash(state),
Array(a, n) => { a.hash(state); n.hash(state) },
Repeat(a, n) => { a.hash(state); n.hash(state) },
Char(c) => c.hash(state),
Dummy => ().hash(state),
}
}
}
/// Note that equality for `ConstVal` means that the it is the same
/// constant, not that the rust values are equal. In particular, `NaN
/// == NaN` (at least if it's the same NaN; distinct encodings for NaN
/// are considering unequal).
impl PartialEq for ConstVal {
fn eq(&self, other: &ConstVal) -> bool {
match (self, other) {
(&Float(a), &Float(b)) => unsafe{transmute::<_,u64>(a) == transmute::<_,u64>(b)},
(&Integral(a), &Integral(b)) => a == b,
(&Str(ref a), &Str(ref b)) => a == b,
(&ByteStr(ref a), &ByteStr(ref b)) => a == b,
(&Bool(a), &Bool(b)) => a == b,
(&Struct(a), &Struct(b)) => a == b,
(&Tuple(a), &Tuple(b)) => a == b,
(&Function(a), &Function(b)) => a == b,
(&Array(a, an), &Array(b, bn)) => (a == b) && (an == bn),
(&Repeat(a, an), &Repeat(b, bn)) => (a == b) && (an == bn),
(&Char(a), &Char(b)) => a == b,
(&Dummy, &Dummy) => true, // FIXME: should this be false?
_ => false,
}
}
}
impl Eq for ConstVal { }
impl ConstVal {
pub fn description(&self) -> &'static str {
match *self {
Float(_) => "float",
Float(f) => f.description(),
Integral(i) => i.description(),
Str(_) => "string literal",
ByteStr(_) => "byte string literal",