LLVM: llvm::LegalizeActions Namespace Reference (original) (raw)
| Enumerations | |
|---|---|
| enum | LegalizeAction : std::uint8_t { Legal, NarrowScalar, WidenScalar, FewerElements, MoreElements, Bitcast, Lower, Libcall, Custom, Unsupported, NotFound, UseLegacyRules } |
◆ LegalizeAction
enum llvm::LegalizeActions::LegalizeAction : std::uint8_t
| Enumerator | |
|---|---|
| Legal | The operation is expected to be selectable directly by the target, and no transformation is necessary. |
| NarrowScalar | The operation should be synthesized from multiple instructions acting on a narrower scalar base-type. For example a 64-bit add might be implemented in terms of 32-bit add-with-carry. |
| WidenScalar | The operation should be implemented in terms of a wider scalar base-type. For example a <2 x s8> add could be implemented as a <2 x s32> add (ignoring the high bits). |
| FewerElements | The (vector) operation should be implemented by splitting it into sub-vectors where the operation is legal. For example a <8 x s64> add might be implemented as 4 separate <2 x s64> adds. There can be a leftover if there are not enough elements for last sub-vector e.g. <7 x s64> add will be implemented as 3 separate <2 x s64> adds and one s64 add. Leftover types can be avoided by doing MoreElements first. |
| MoreElements | The (vector) operation should be implemented by widening the input vector and ignoring the lanes added by doing so. For example <2 x i8> is rarely legal, but you might perform an <8 x i8> and then only look at the first two results. |
| Bitcast | Perform the operation on a different, but equivalently sized type. |
| Lower | The operation itself must be expressed in terms of simpler actions on this target. E.g. a SREM replaced by an SDIV and subtraction. |
| Libcall | The operation should be implemented as a call to some kind of runtime support library. For example this usually happens on machines that don't support floating-point operations natively. |
| Custom | The target wants to do something special with this combination of operand and type. A callback will be issued when it is needed. |
| Unsupported | This operation is completely unsupported on the target. A programming error has occurred. |
| NotFound | Sentinel value for when no action was found in the specified table. |
| UseLegacyRules | Fall back onto the old rules. TODO: Remove this once we've migrated |
Definition at line 45 of file LegalizerInfo.h.