diff options
Diffstat (limited to 'compiler/rustc_middle/src/mir/syntax.rs')
| -rw-r--r-- | compiler/rustc_middle/src/mir/syntax.rs | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs index f8ee59f306f..3b7eb820df8 100644 --- a/compiler/rustc_middle/src/mir/syntax.rs +++ b/compiler/rustc_middle/src/mir/syntax.rs @@ -311,6 +311,7 @@ pub enum StatementKind<'tcx> { /// Describes what kind of retag is to be performed. #[derive(Copy, Clone, TyEncodable, TyDecodable, Debug, PartialEq, Eq, Hash, HashStable)] +#[rustc_pass_by_value] pub enum RetagKind { /// The initial retag when entering a function. FnEntry, @@ -990,11 +991,19 @@ pub enum Rvalue<'tcx> { /// matching types and return a value of that type. BinaryOp(BinOp, Box<(Operand<'tcx>, Operand<'tcx>)>), - /// Same as `BinaryOp`, but yields `(T, bool)` instead of `T`. In addition to performing the - /// same computation as the matching `BinaryOp`, checks if the infinite precison result would be - /// unequal to the actual result and sets the `bool` if this is the case. + /// Same as `BinaryOp`, but yields `(T, bool)` with a `bool` indicating an error condition. /// - /// This only supports addition, subtraction, multiplication, and shift operations on integers. + /// When overflow checking is disabled, the error condition is false. Otherwise, the error + /// condition is determined as described below. + /// + /// For addition, subtraction, and multiplication on integers the error condition is set when + /// the infinite precision result would be unequal to the actual result. + /// + /// For shift operations on integers the error condition is set when the value of right-hand + /// side is greater than or equal to the number of bits in the type of the left-hand side, or + /// when the value of right-hand side is negative. + /// + /// Other combinations of types and operators are unsupported. CheckedBinaryOp(BinOp, Box<(Operand<'tcx>, Operand<'tcx>)>), /// Computes a value as described by the operation. |