[#llvm-AAResults-onlyReadsMemory-04]
= xref:llvm.adoc[llvm]::xref:llvm/AAResults.adoc[AAResults]::onlyReadsMemory
:relfileprefix: ../../
:mrdocs:

Checks if the specified function is known to only read from non‐volatile memory (or not access memory at all).

== Synopsis

Declared in `<llvm/Analysis/AliasAnalysis.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
bool
onlyReadsMemory(xref:llvm/Function.adoc[Function] const* F);
----

== Description

Functions that unwind the stack are legal for this predicate.

This property allows many common optimizations to be performed in the absence of interfering store instructions, such as CSE of strlen calls.

This property corresponds to the GCC 'pure' attribute.

== Return Value

True if the function only reads non‐volatile memory or does not access memory.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *F*
| Function to test.
|===


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