GCC-PR rtl-optimization/34628
* combine.c (try_combine): Stop and undo after the first combination
if an autoincrement side-effect on the first insn has effectively
been lost.
The issue was detected in OpenBSD but their fix was not very good. Huge
thanks to the upstream author, Eric Botcazou, for permitting the use of
this patch under GPLv2.
MFC after: 5 days
non-i386, non-unix, and generatable files have been trimmed, but can easily
be added in later if needed.
gcc-2.7.2.1 will follow shortly, it's a very small delta to this and it's
handy to have both available for reference for such little cost.
The freebsd-specific changes will then be committed, and once the dust has
settled, the bmakefiles will be committed to use this code.
