https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96612
Bug ID: 96612
Summary: [11 Regression][submitted patch] Fails to bootstrap
with older --build= than --host= compiler due to
missing -std=c++11
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Keywords: build, patch
Severity: normal
Priority: P3
Component: bootstrap
Assignee: unassigned at gcc dot gnu.org
Reporter: burnus at gcc dot gnu.org
Target Milestone: ---
Patch: https://gcc.gnu.org/pipermail/gcc-patches/2020-August/551900.html
The issue occurs when doing a cross build with
--build= being a GCC 5.2 compiler
--host= being a GCC 8.2 compiler
While the latter supports C++11 out of the box, GCC 5 still needs --std=c++11
in order to compile C++11. The configure check only checks the ${host} compiler
but not the ${build} / CXX_FOR_BUILD compiler – hence, no flag is added.
I think the proper solution is to do the C++11 check also for the CXX_FOR_BUILD
compiler, as done in the patch linked above,
https://gcc.gnu.org/pipermail/gcc-patches/2020-August/551900.html
... but technically it is a regression as reverting the following commits also
fixes the build:
commit https://gcc.gnu.org/g:d59a576b8b5e12c3a56f0262912090e2921f5daa
Redefine NULL to nullptr
2020-06-30
plus the three patches
commit https://gcc.gnu.org/g:20a2e6afa82c165bcd1a8749478e9402a25088a4
recog: Restore builds with Clang
Workaround forhttps://bugs.llvm.org/show_bug.cgi?id=46377
2020-06-22
which was the follow up to
commit https://gcc.gnu.org/g:4e49b994de060d4a6c9318d0ed52ef038153426e
recog: Tweak insn_gen_fn::operator() definition
2020-06-17
which was the follow-up patch to
commit https://gcc.gnu.org/g:3a179232a743b2b1987b21034cd5bb3bc660ee85
recog: Use parameter packs for operator()
2020-06-12
