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Implement remaining `unchecked` arithmetic intrinsics

This commit is contained in:
Dylan MacKenzie 2020-02-04 17:09:22 -08:00
parent 040d9873aa
commit 78f8ad3640
2 changed files with 22 additions and 2 deletions
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19
src/librustc_mir/interpret/intrinsics.rs
View File

@ -218,19 +218,34 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
};
self.write_scalar(val, dest)?;
}
sym::unchecked_shl | sym::unchecked_shr => {
sym::unchecked_shl
| sym::unchecked_shr
| sym::unchecked_add
| sym::unchecked_sub
| sym::unchecked_mul
| sym::unchecked_div
| sym::unchecked_rem => {
let l = self.read_immediate(args[0])?;
let r = self.read_immediate(args[1])?;
let bin_op = match intrinsic_name {
sym::unchecked_shl => BinOp::Shl,
sym::unchecked_shr => BinOp::Shr,
sym::unchecked_add => BinOp::Add,
sym::unchecked_sub => BinOp::Sub,
sym::unchecked_mul => BinOp::Mul,
sym::unchecked_div => BinOp::Div,
sym::unchecked_rem => BinOp::Rem,
_ => bug!("Already checked for int ops"),
};
let (val, overflowed, _ty) = self.overflowing_binary_op(bin_op, l, r)?;
if overflowed {
let layout = self.layout_of(substs.type_at(0))?;
let r_val = self.force_bits(r.to_scalar()?, layout.size)?;
throw_ub_format!("Overflowing shift by {} in `{}`", r_val, intrinsic_name);
if let sym::unchecked_shl | sym::unchecked_shr = intrinsic_name {
throw_ub_format!("Overflowing shift by {} in `{}`", r_val, intrinsic_name);
} else {
throw_ub_format!("Overflow executing `{}`", intrinsic_name);
}
}
self.write_scalar(val, dest)?;
}

5
src/librustc_span/symbol.rs
View File

@ -755,8 +755,13 @@ symbols! {
u64,
u8,
unboxed_closures,
unchecked_add,
unchecked_div,
unchecked_mul,
unchecked_rem,
unchecked_shl,
unchecked_shr,
unchecked_sub,
underscore_const_names,
underscore_imports,
underscore_lifetimes,