Enum flowistry_pdg::rustc::mir::NonDivergingIntrinsic

pub enum NonDivergingIntrinsic<'tcx> {
    Assume(Operand<'tcx>),
    CopyNonOverlapping(CopyNonOverlapping<'tcx>),
}

Variants

Assume(Operand<'tcx>)

Denotes a call to the intrinsic function assume.

The operand must be a boolean. Optimizers may use the value of the boolean to backtrack its computation to infer information about other variables. So if the boolean came from a x < y operation, subsequent operations on x and y could elide various bound checks. If the argument is false, this operation is equivalent to TerminatorKind::Unreachable.

CopyNonOverlapping(CopyNonOverlapping<'tcx>)

Denotes a call to the intrinsic function copy_nonoverlapping.

First, all three operands are evaluated. src and dest must each be a reference, pointer, or Box pointing to the same type T. count must evaluate to a usize. Then, src and dest are dereferenced, and count * size_of::<T>() bytes beginning with the first byte of the src place are copied to the contiguous range of bytes beginning with the first byte of dest.

Needs clarification: In what order are operands computed and dereferenced? It should probably match the order for assignment, but that is also undecided.

Needs clarification: Is this typed or not, ie is there a typed load and store involved? I vaguely remember Ralf saying somewhere that he thought it should not be.