Struct rustc_mir_transform::match_branches::SimplifyToExp

struct SimplifyToExp {
    transfrom_kinds: Vec<TransfromKind>,
}

Fields

transfrom_kinds: Vec<TransfromKind>

Trait Implementations

impl Default for SimplifyToExp

fn default() -> SimplifyToExp

Returns the “default value” for a type.

impl<'tcx> SimplifyMatch<'tcx> for SimplifyToExp

If we find that the value of match is the same as the assignment, merge a target block statements into the source block, using cast to transform different integer types.

For example:

bb0: {
    switchInt(_1) -> [1: bb2, 2: bb3, 3: bb4, otherwise: bb1];
}

bb1: {
    unreachable;
}

bb2: {
    _0 = const 1_i16;
    goto -> bb5;
}

bb3: {
    _0 = const 2_i16;
    goto -> bb5;
}

bb4: {
    _0 = const 3_i16;
    goto -> bb5;
}

into:

bb0: {
   _0 = _3 as i16 (IntToInt);
   goto -> bb5;
}

fn can_simplify( &mut self, tcx: TyCtxt<'tcx>, targets: &SwitchTargets, param_env: ParamEnv<'tcx>, bbs: &IndexSlice<BasicBlock, BasicBlockData<'tcx>>, discr_ty: Ty<'tcx>, ) -> Option<()>

Check that the BBs to be simplified satisfies all distinct and that the terminator are the same. There are also conditions for different ways of simplification.

fn new_stmts( &self, _tcx: TyCtxt<'tcx>, targets: &SwitchTargets, _param_env: ParamEnv<'tcx>, patch: &mut MirPatch<'tcx>, parent_end: Location, bbs: &IndexSlice<BasicBlock, BasicBlockData<'tcx>>, discr_local: Local, discr_ty: Ty<'tcx>, )

fn simplify( &mut self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, switch_bb_idx: BasicBlock, param_env: ParamEnv<'tcx>, ) -> Option<()>

Simplifies a match statement, returning true if the simplification succeeds, false otherwise. Generic code is written here, and we generally don’t need a custom implementation.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 24 bytes