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Bug 878987

Summary: sci-libs/openblas-0.3.20 fails to compile (lto): lapack.h:6994:6: error: type of [-Werror=lto-type-mismatch]
Product: Gentoo Linux Reporter: Agostino Sarubbo <ago>
Component: Current packagesAssignee: Gentoo Science Related Packages <sci>
Status: RESOLVED FIXED    
Severity: normal CC: lumin, mjo
Priority: Normal    
Version: unspecified   
Hardware: All   
OS: Linux   
URL: https://github.com/xianyi/OpenBLAS/issues/4128
Whiteboard:
Package list:
Runtime testing required: ---
Bug Depends on:    
Bug Blocks: 618550    
Attachments: build.log.xz

Description Agostino Sarubbo gentoo-dev 2022-11-01 09:19:02 UTC
https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: sci-libs/openblas-0.3.20 fails to compile (lto).
Discovered on: amd64 (internal ref: lto_tinderbox)

NOTE:
This machine uses lto with CFLAGS=-flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing

Here is a bit of explanation:

-Werror=lto-type-mismatch:
User to find possible runtime issues in packages. It likely means the package is unsafe to build & use with LTO.
For projects using the same identifier but with different types across different files, they must be fixed to be consistent across the codebase.

-Werror=odr:
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO. C++ code must comply with the One Definition Rule (ODR) - see https://en.cppreference.com/w/cpp/language/definition#One_Definition_Rule.

-Werror=strict-aliasing:
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO.

Workarounds:
- If upstream is friendly and still active, file a bug upstream. For emulators, codecs, games, or multimedia packages, it may be worth just applying a workaround instead, as upstreams sometimes aren't receptive to these bugs (VALID FOR ALL).
- Use the new 'filter-lto' from flag-o-matic.eclass as it's likely to be unsafe with LTO (VALID FOR lto-type-mismatch - odr).
- Fix it yourself if interested, of course (VALID FOR ALL).
- Append-flags -fno-strict-aliasing (VALID FOR strict-aliasing).
- Use memcpy() but a union is sometimes suitable too (VALID FOR strict-aliasing).
- -fstrict-aliasing is implied by -O2, so this must be addressed in some form (VALID FOR strict-aliasing).

See also: https://marc.info/?l=gentoo-dev&m=165639574126280&w=2
Comment 1 Agostino Sarubbo gentoo-dev 2022-11-01 09:19:05 UTC
Created attachment 826275 [details]
build.log.xz

build log and emerge --info (compressed because it exceeds attachment limit, use 'xzless' to read it)
Comment 2 Larry the Git Cow gentoo-dev 2023-07-09 16:21:26 UTC
The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=6a29b8c181bb98a32bc2a7c21589631d93ea6880

commit 6a29b8c181bb98a32bc2a7c21589631d93ea6880
Author:     Michael Orlitzky <mjo@gentoo.org>
AuthorDate: 2023-07-09 16:16:54 +0000
Commit:     Michael Orlitzky <mjo@gentoo.org>
CommitDate: 2023-07-09 16:19:36 +0000

    sci-libs/openblas: disable LTO for now.
    
    There's an upstream issue open for the type mismatches, but it doesn't
    look like an easy fix. For now we work around it by disabling LTO, which
    disables -Werror=lto-type-mismatch as well.
    
    Closes: https://bugs.gentoo.org/878987
    Signed-off-by: Michael Orlitzky <mjo@gentoo.org>

 sci-libs/openblas/openblas-0.3.23.ebuild | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)