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

Fold a constant‐predicated terminator into an unconditional branch.

== Synopsis

Declared in `<llvm/Transforms/Utils/Local.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
bool
ConstantFoldTerminator(
    xref:llvm/BasicBlock.adoc[BasicBlock]* BB,
    bool DeleteDeadConditions = false,
    xref:llvm/TargetLibraryInfo.adoc[TargetLibraryInfo] const* TLI = nullptr,
    xref:llvm/DomTreeUpdater.adoc[DomTreeUpdater]* DTU = nullptr);
----

== Description

If a terminator instruction is predicated on a constant value, convert it into an unconditional branch to the constant destination. This is a nontrivial operation because the successors of this basic block must have their PHI nodes updated. Also calls RecursivelyDeleteTriviallyDeadInstructions() on any branch/switch conditions and indirectbr addresses this might make dead if DeleteDeadConditions is true.

== Return Value

True if the terminator was folded into an unconditional branch.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *BB*
| Basic block whose terminator may be folded.
| *DeleteDeadConditions*
| Whether to delete conditions made dead by the fold.
| *TLI*
| Optional target library info for dead‐instruction analysis.
| *DTU*
| Optional dominator‐tree updater for CFG changes.
|===


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