[#llvm-LiveIntervals-getSpillWeight-05]
= xref:llvm.adoc[llvm]::xref:llvm/LiveIntervals.adoc[LiveIntervals]::getSpillWeight
:relfileprefix: ../../
:mrdocs:

Calculate the spill weight to assign to a basic block.

== Synopsis

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

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
static
float
getSpillWeight(
    bool isDef,
    bool isUse,
    xref:llvm/MachineBlockFrequencyInfo.adoc[MachineBlockFrequencyInfo] const* MBFI,
    xref:llvm/MachineBasicBlock.adoc[MachineBasicBlock] const* MBB,
    xref:llvm/ProfileSummaryInfo.adoc[ProfileSummaryInfo]* PSI = nullptr);
----

== Description

If `PSI` is provided the calculation is altered for optsize functions.

== Return Value

Computed spill weight for the basic block.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *isDef*
| True if the register is defined in the block.
| *isUse*
| True if the register is used in the block.
| *MBFI*
| Block frequency info used to weight the spill cost.
| *MBB*
| Basic block whose spill weight is computed.
| *PSI*
| Optional profile summary used for size‐optimized functions.
|===


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