On July 17, 2015 11:28:28 PM GMT+02:00, Ulrich Weigand <uweig...@de.ibm.com> wrote: >On July 17, 2015 6:54:32 PM GMT+02:00, Ulrich Weigand ><uweig...@de.ibm.com> wrote: >> >So do we now consider host compilers < 4.3 (4?) unsupported for >> >building >> >mainline GCC, or should we try to work around the issue (e.g. by >moving >> >the allocator out-of-line or using some other aliasing barrier)? >> >> Why is this an issue for stage1 which runs w/o optimization? > >Well, this is the SPU compiler on a Cell system, which is technically >a cross compiler from PowerPC (even though the resulting binaries run >natively on the machine). > >> For cross compiling we already suggest using known good compilers. > >The documentation says: > > To build a cross compiler, we recommend first building and installing > a native compiler. You can then use the native GCC compiler to build > the cross compiler. The installed native compiler needs to be GCC > version 2.95 or later.
I think that needs updating anyway since even for crosses we now require a C++04 conforming host compiler. >So building with a native GCC 4.1 seems to have been officially >supported until now as far as I can tell (unless you're building Ada). > > >Now, I could certainly live with a statement that cross compilers can >only be build with a native GCC 4.3 or newer; but that should be IMO >a deliberate decision and be widely announced (maybe even verified >by a configure check?), so that others don't run into the problem; >the nature of its symptoms make the problem difficult to diagnose. The requirement is to have a bug-free host compiler or use flags that make it appear bug-free. Which is why we use -O0 when bootstrapping... Yes, we could detect appropriate host gcc versions at configure time and apply a workaround (use -fno-strict-aliasing) for too old GCC. Richard. > >Bye, >Ulrich
