[Bug testsuite/109951] [14 Regression] libgomp, testsuite: non-native multilib c++ tests fail on Darwin.

[tschwinge at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109951

Thomas Schwinge <tschwinge at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |macro at orcam dot me.uk
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2023-05-25
     Ever confirmed|0                           |1

--- Comment #3 from Thomas Schwinge <tschwinge at gcc dot gnu.org> ---
Iain, sorry for this; let's track this down.

Looking at your "test x86_64 multilib on i686" case.

First, is my understanding correct, that 'GXX_UNDER_TEST'
'i686-apple-darwin9/libgomp/testsuite/site.exp' does contain the correct
flags/paths for the default ("native", "i686") multilib, but incorrect for the
other ("non-native", "x86_64") multilib?  Conversely, would
'i686-apple-darwin9/x86_64/libgomp/testsuite/site.exp' contain the correct
flags/paths for the other ("non-native", "x86_64") multilib?  (..., but that
latter file is never used, always the former 'site.exp'; similar to my "Indeed
there is some confusion there" comment in
<https://inbox.sourceware.org/87bkivayue.fsf@euler.schwinge.homeip.net> -- but
that one's benign, in contrast to your case).

Second, do you not have similar confusion in 'GCC_UNDER_TEST' and
'GFORTRAN_UNDER_TEST' flags/paths?

(May help me to attach all the relevant 'site.exp' files.)

Third, see Maciej's Subversion r279708 (Git commit
c8e759b4215ba4b376c9d468aeffe163b3d520f0) "libgomp/test: Fix compilation for
build sysroot", followed by Git commit 749bd22ddc50b5112e5ed506ffef7249bf8e6fb3
"libgomp/test: Remove a build sysroot fix regression" (for libgomp, and
similarly other commits for a number of (but not all?) other GCC target
libraries).  This is what started capturing 'CC' for test-time use as
'GCC_UNDER_TEST', and this is what in recent commit
11f4d483600b5788a3d1cf1527e838e4a7ed1455 "libgomp testsuite: As appropriate,
use the 'gcc', 'g++', 'gfortran' driver [PR91884]" I've then extended for
'CXX': 'GXX_UNDER_TEST', 'FC': 'GFORTRAN_UNDER_TEST'.  I however don't
understand yet the original intent of his change; in my understanding, and as
has been the case before, we'd just get 'GCC_UNDER_TEST' etc. populated by
'find_gcc' etc.