[Bug target/71399] [5/6/7 Regression] 5.3.0 bootstrap comparison failure on arm-linux-gnueabihf

["ludo at gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71399

--- Comment #10 from Ludovic Courtès <ludo at gnu dot org> ---
In fact, the revert only needs to be done on the initial pseudo-cross-compiler
that is used to build the native compiler (I'm attaching a PDF of the
dependency graph, where the initial pseudo-cross-compiler as described at
http://linuxfromscratch.org/lfs/view/stable/chapter05/gcc-pass1.html is marked
as "gcc-cross-boot0", and the final native compiler is simply "gcc").

To summarize, if we build 4.9.4 with a cross-4.9.3, that's fine; if we build
4.9.4 with a cross-4.9.4, we get the bootstrap comparison failure.

That would suggest a code generation issue that somehow propagates from the
initial cross-compiler up to stage2 of the compiler we're building.