[Bug target/97827] bootstrap error building the amdgcn-amdhsa offload compiler with LLVM 11

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97827

--- Comment #18 from Tobias Burnus <burnus at gcc dot gnu.org> ---
POST SCRIPT / STATUS UPDATE (This PR remains FIXED)

(In reply to Tobias Burnus from comment #16)
> > I unfortunately missed in my the LLVM patch that '.rodata' implies flags and
> > messed up the check. Should by fixed by: https://reviews.llvm.org/D94072
> 
> Now merged to LLVM 12/trunk (see ↑ or next link); for LLVM 11 backporting,
> see: https://bugs.llvm.org/show_bug.cgi?id=48922

For completeness:

It turned out that it missed the LLVM 12 branch point - such that is is only in
LLVM 13+ and not LLVM 12. (The LLVM 11 request was also ignored.)

 * * *

Additionally, a very hard to hit corner case was missed that became easier to
trigger due to an LLVM 13 change. - That one is still rare to hit (and does not
prevent bootstrapping).
It was fixed in LLVM 'main' and backported to LLVM releases/13.x (just after
13.0.1-RC1); thus, it will be in RC2 (if any) and 13.0.1.

Cf. https://reviews.llvm.org/D114717
main:
 
https://github.com/llvm/llvm-project/commit/c01c62c76c60a5a5da0496e41faae907944c92dd
LLVM 13.x backport (for 13.0.1):
  https://github.com/llvm/llvm-project/issues/52607
 
https://github.com/llvm/llvm-project/commit/5932c004778cf251302db0d46d1dfb247325ed3f

Thus: FIXED (only) in LLVM 13 - but best to use at least LLVM release/13.x or
13.0.1(-rc2).

* * *

GCC 12 also has several changes (mostly: configure checks to detect and act on
the LLVM version) - to be able to use LLVM 13; several were backported to GCC
11 (releases/gcc-11).

* * *

Crossref: PR 100181 (-> PR 100181 comment 10) is another GCN-related issue,
which was solved in LLVM 13