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

Find the def instruction for `Reg,` and underlying value Register folding away any copies.

== Synopsis

Declared in `<llvm/CodeGen/GlobalISel/Utils.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
std::optional<DefinitionAndSourceRegister>
getDefSrcRegIgnoringCopies(
    xref:llvm/Register.adoc[Register] Reg,
    xref:llvm/MachineRegisterInfo.adoc[MachineRegisterInfo] const& MRI);
----

== Description

Also walks through hints such as G_ASSERT_ZEXT.

== Return Value

The def instruction and source register, or std::nullopt.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *Reg*
| Virtual register whose definition is sought.
| *MRI*
| Register information for the function.
|===


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