Bug 909196

Summary:	dev-lang/python[lto] compiles in single thread, ignores -flto cflags
Product:	Gentoo Linux	Reporter:	om3i <r9ku1q>
Component:	Current packages	Assignee:	Python Gentoo Team <python>
Status:	UNCONFIRMED ---
Severity:	normal
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description om3i 2023-06-26 16:03:54 UTC

To be more specific, the linker plugin only performs half of the compilation in a single thread. This is because configure.ac overrides the user-specified flags:
-flto=12 -flto-compression-level=0
with these flags:
LTOFLAGS="-flto ... -flto-partition=none"
I understand that single-threaded lto may produce better optimization, but I don't think it's worth the trade-off.

Reproducible: Always

Comment 1 Sam James archtester

2023-06-26 16:13:32 UTC

This is more nuanced than it appears, in that the reason we do USE=lto for the configure argument is because for years, the configure test was broken.

This has finally been fixed in autoconf-archive via https://github.com/autoconf-archive/autoconf-archive/pull/279, but it's not yet in a release.