[#llvm-DefaultEvictionAdvisor]
= xref:llvm.adoc[llvm]::DefaultEvictionAdvisor
:relfileprefix: ../
:mrdocs:

Default heuristic eviction advisor used by greedy register allocation.

== Synopsis

Declared in `<llvm/CodeGen/RegAllocEvictionAdvisor.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class DefaultEvictionAdvisor
    : public xref:llvm/RegAllocEvictionAdvisor.adoc[RegAllocEvictionAdvisor]
----

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `xref:llvm/RegAllocEvictionAdvisor.adoc[RegAllocEvictionAdvisor]`
| Interface to the eviction advisor for choosing live ranges to evict.
|===

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:llvm/DefaultEvictionAdvisor/2constructor.adoc[`DefaultEvictionAdvisor`]         [.small]#[constructor]#
| Construct the default advisor for `MF` and allocator `RA.`
| xref:llvm/RegAllocEvictionAdvisor/canEvictHintInterference.adoc[`canEvictHintInterference`]  [.small]#[virtual]#
| Find out if we can evict the live ranges occupying the given PhysReg, which is a hint (preferred register) for VirtReg.
| xref:llvm/RegAllocEvictionAdvisor/isUnusedCalleeSavedReg.adoc[`isUnusedCalleeSavedReg`] 
| Returns true if the given `PhysReg` is a callee saved register and has not been used for allocation yet.
| xref:llvm/RegAllocEvictionAdvisor/isUrgentEviction.adoc[`isUrgentEviction`] 
| Returns true if this is an urgent eviction.
| xref:llvm/RegAllocEvictionAdvisor/tryFindEvictionCandidate.adoc[`tryFindEvictionCandidate`]  [.small]#[virtual]#
| Find a physical register that can be freed by eviction, or NoRegister.
|===


== Protected Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:llvm/RegAllocEvictionAdvisor/canAllocatePhysReg.adoc[`canAllocatePhysReg`] 
| Return true if allocating `PhysReg` is worthwhile under the cost limit.
| xref:llvm/RegAllocEvictionAdvisor/canReassign.adoc[`canReassign`] 
| Return true if `VirtReg` can be reassigned away from `FromReg.`
| xref:llvm/RegAllocEvictionAdvisor/getOrderLimit.adoc[`getOrderLimit`] 
| Get the upper limit of elements in `Order` that need to be analyzed.
|===


== Protected Data Members

[cols="1,4"]
|===
| Name| Description
| xref:llvm/RegAllocEvictionAdvisor/EnableLocalReassign.adoc[`EnableLocalReassign`] 
| Run or not the local reassignment heuristic. This information is obtained from the TargetSubtargetInfo.
| xref:llvm/RegAllocEvictionAdvisor/LIS.adoc[`LIS`] 
| Live interval analysis for the current function.
| xref:llvm/RegAllocEvictionAdvisor/MF.adoc[`MF`] 
| Machine function currently being allocated.
| xref:llvm/RegAllocEvictionAdvisor/MRI.adoc[`MRI`] 
| Machine register info for the current function.
| xref:llvm/RegAllocEvictionAdvisor/Matrix.adoc[`Matrix`] 
| Live register matrix used to query interference.
| xref:llvm/RegAllocEvictionAdvisor/RA.adoc[`RA`] 
| Greedy register allocator that owns related analyses.
| xref:llvm/RegAllocEvictionAdvisor/RegClassInfo.adoc[`RegClassInfo`] 
| Cached register class information for the current function.
| xref:llvm/RegAllocEvictionAdvisor/RegCosts.adoc[`RegCosts`] 
| Per‐physical‐register cost‐per‐use values.
| xref:llvm/RegAllocEvictionAdvisor/TRI.adoc[`TRI`] 
| Target register info for the current subtarget.
| xref:llvm/RegAllocEvictionAdvisor/VRM.adoc[`VRM`] 
| Mapping from virtual to physical registers.
|===



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