From: Sandra Loosemore <sloosemore@baylibre.com>
Date: Tue, 15 Apr 2025 03:49:06 +0000 (+0000)
Subject: Doc: always_inline attribute vs multiple TUs and LTO [PR113203]
X-Git-Tag: basepoints/gcc-16~78
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fc89b1face0d207710eaa3d8f5af3adcffd5c5c9;p=thirdparty%2Fgcc.git

Doc: always_inline attribute vs multiple TUs and LTO [PR113203]

gcc/ChangeLog
	PR ipa/113203
	* doc/extend.texi (Common Function Attributes): Explain how to
	use always_inline in programs that have multiple translation
	units, and that LTO inlining additionally needs optimization
	enabled.
---

diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 3a8e5706515..5bc2785f802 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -1933,6 +1933,13 @@ Note that if such a function is called indirectly the compiler may
 or may not inline it depending on optimization level and a failure
 to inline an indirect call may or may not be diagnosed.
 
+If you need to use the inlined function in multiple translation units,
+you should put the @code{always_inline} attribute on a function
+definition in a header file that is included in all translation units
+where the function is used.  Link-time optimization can inline
+functions across translation units, but only if an optimization level
+that normally enables inlining is additionally specified.
+
 @cindex @code{artificial} function attribute
 @item artificial
 This attribute is useful for small inline wrappers that if possible