[Bug c/65020] New: [5.0 regression] bootstrap failed on arm because of r219789

["jiwang at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65020

            Bug ID: 65020
           Summary: [5.0 regression] bootstrap failed on arm because of
                    r219789
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jiwang at gcc dot gnu.org

I have run into bootstrap failure issue recently. and narrowed down into
r219789

commit 34aaed439380226950d65f37c02a549dfdebb16c
Author: mkuvyrkov <mkuvyrkov@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Sat Jan 17 01:06:43 2015 +0000

    Model cache auto-prefetcher in scheduler

reproduced the following error on two chrome book.

../gcc/configure --enable-languages=c,c++ --with-float=hard --with-arch=armv7-a
--with-tune=cortex-a15


make[2]: Entering directory `/home/jiowan01/build-boot-strap-without'
make[3]: Entering directory `/home/jiowan01/build-boot-strap-without'
rm -f stage_current
make[3]: Leaving directory `/home/jiowan01/build-boot-strap-without'
Comparing stages 2 and 3
warning: gcc/cc1-checksum.o differs
warning: gcc/cc1plus-checksum.o differs
Bootstrap comparison failure!
gcc/tree-vect-slp.o differs
gcc/tree-ssa-reassoc.o differs
gcc/expmed.o differs
gcc/opts.o differs
gcc/ipa-icf.o differs
gcc/ira.o differs
gcc/gimple-walk.o differs
gcc/function.o differs
gcc/tree-sra.o differs
gcc/et-forest.o differs
gcc/lto-wrapper.o differs
gcc/lto/lto.o differs
gcc/varasm.o differs
gcc/fold-const.o differs
gcc/cp/pt.o differs
gcc/cp/method.o differs
gcc/cp/init.o differs
gcc/cp/call.o differs
gcc/ira-emit.o differs
gcc/dwarf2out.o differs
gcc/ira-costs.o differs
gcc/lra-assigns.o differs
gcc/omp-low.o differs
gcc/bt-load.o differs
gcc/tree-switch-conversion.o differs
gcc/tree-vect-patterns.o differs
gcc/tree-ssa-loop-ivopts.o differs
libbacktrace/dwarf.o differs
libcpp/expr.o differs
libdecnumber/decNumber.o differs
libiberty/simple-object-xcoff.o differs
libiberty/pic/simple-object-xcoff.o differs
make[2]: *** [compare] Error 1
make[2]: Leaving directory `/home/jiowan01/build-boot-strap-without'
make[1]: *** [stage3-bubble] Error 2
make[1]: Leaving directory `/home/jiowan01/build-boot-strap-without'
make: *** [all] Error 2