[Bug c/112782] New: [14 Regression] stage2/3 differs when compiled with -mfix-r5900 on mips

["immoloism at googlemail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112782

            Bug ID: 112782
           Summary: [14 Regression] stage2/3 differs when compiled with
                    -mfix-r5900 on mips
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: immoloism at googlemail dot com
  Target Milestone: ---

While testing GCC-14 support in Gentoo I have found an interesting issue where
GCC no longer builds correctly when setting -mfix-r5900. With the help of Sam
James we have confirmed this causes the error in the stage 2 and 3 checks
however I have been unable to find where this breakage started so far and can
only confirm there is no issue using the flag with versions 12 and 13.

To reproduce: (sorry for vague steps but I normally use portage to manage this)

Setup a MIPS install (cross compiling does not hit the issue)
Set CFLAGS to "-Os -march=mips3 -mabi=32 -mplt  -pipe -mfix-r5900"
Compile GCC14 as normal

Error:

Comparing stages 2 and 3
Bootstrap comparison failure!
gcc/spellcheck.o differs
gcc/tree-data-ref.o differs
gcc/asan.o differs
gcc/pointer-query.o differs
gcc/tree-ssa-math-opts.o differs
gcc/lto/lto-common.o differs
gcc/lto/lto-partition.o differs
gcc/tree-vectorizer.o differs
gcc/gimple-range-op.o differs
gcc/dwarf2out.o differs
gcc/gimple-match-4.o differs
gcc/gimple-ssa-warn-restrict.o differs
gcc/tree-chrec.o differs
gcc/function.o differs
gcc/tree-vect-loop-manip.o differs
gcc/tree-vrp.o differs
gcc/gimple-array-bounds.o differs
gcc/generic-match-2.o differs
gcc/tree-vect-patterns.o differs
gcc/gimple-match-5.o differs
gcc/simplify-rtx.o differs
gcc/tree-vect-data-refs.o differs
gcc/tree-vect-slp.o differs
gcc/tree-ssa-alias.o differs
gcc/ipa-fnsummary.o differs
gcc/tree.o differs
gcc/tree-scalar-evolution.o differs
gcc/splay-tree-utils.o differs
gcc/lto-streamer-in.o differs
gcc/fortran/trans-array.o differs
gcc/fortran/trans-intrinsic.o differs
gcc/fortran/interface.o differs
gcc/fortran/frontend-passes.o differs
gcc/fortran/openmp.o differs
gcc/fortran/trans-common.o differs
gcc/fortran/parse.o differs
gcc/vr-values.o differs
gcc/predict.o differs
gcc/var-tracking.o differs
gcc/mips.o differs
gcc/gimple-walk.o differs
gcc/tree-switch-conversion.o differs
gcc/tree-ssa-loop-prefetch.o differs
gcc/optabs.o differs
gcc/rtl-ssa/accesses.o differs
gcc/omp-offload.o differs
gcc/tree-ssa-phiopt.o differs
gcc/symtab.o differs
gcc/gimple-match-7.o differs
gcc/value-range.o differs
gcc/tree-ssa-operands.o differs
gcc/sel-sched-ir.o differs
gcc/tree-ssa-sink.o differs
gcc/tree-ssa-reassoc.o differs
gcc/analyzer/region-model.o differs
gcc/analyzer/checker-path.o differs
gcc/analyzer/program-point.o differs
gcc/analyzer/sm-file.o differs
gcc/analyzer/region.o differs
gcc/analyzer/call-details.o differs
gcc/analyzer/diagnostic-manager.o differs
gcc/analyzer/sm-fd.o differs
gcc/analyzer/sm-malloc.o differs
gcc/analyzer/record-layout.o differs
gcc/analyzer/constraint-manager.o differs
gcc/analyzer/program-state.o differs
gcc/analyzer/access-diagram.o differs
gcc/analyzer/infinite-recursion.o differs
gcc/analyzer/call-summary.o differs
gcc/analyzer/engine.o differs
gcc/analyzer/store.o differs
gcc/analyzer/supergraph.o differs
gcc/analyzer/feasible-graph.o differs
gcc/tree-cfg.o differs
gcc/gimple-match-6.o differs
gcc/tree-inline.o differs
gcc/tree-ssa-ccp.o differs
gcc/haifa-sched.o differs
gcc/input.o differs
gcc/loop-init.o differs
gcc/gcov.o differs
gcc/cfgrtl.o differs
gcc/ipa-utils.o differs
gcc/gimple-ssa-warn-access.o differs
gcc/combine.o differs
gcc/wide-int.o differs
gcc/tree-vect-loop.o differs
gcc/gimple-match-8.o differs
gcc/passes.o differs
gcc/cfg.o differs
gcc/ipa-devirt.o differs
gcc/tree-ssa-dom.o differs
gcc/final.o differs
gcc/tree-ssa-loop-unswitch.o differs
gcc/read-md.o differs
gcc/text-art/styled-string.o differs
gcc/text-art/widget.o differs
gcc/text-art/style.o differs
gcc/text-art/table.o differs
gcc/gimple-match-2.o differs
gcc/generic-match-5.o differs
gcc/tree-ssa-threadedge.o differs
gcc/fold-const.o differs
gcc/varasm.o differs
gcc/modulo-sched.o differs
gcc/omp-low.o differs
gcc/tree-pretty-print.o differs
gcc/gimplify.o differs
gcc/gimple-range-path.o differs
gcc/cgraphunit.o differs
gcc/generic-match-4.o differs
gcc/print-rtl.o differs
gcc/sched-deps.o differs
gcc/gimple-ssa-strength-reduction.o differs
gcc/gimple-match-3.o differs
gcc/gimple-fold.o differs
gcc/df-core.o differs
gcc/dwarf2cfi.o differs
gcc/tree-ssa-loop-niter.o differs
gcc/gimple-match-10.o differs
gcc/tree-ssa-uncprop.o differs
gcc/gimple-match-9.o differs
gcc/build/print-rtl.o differs
gcc/build/genmatch.o differs
gcc/build/genrecog.o differs
gcc/build/read-md.o differs
gcc/c-family/c-common.o differs
gcc/c-family/c-omp.o differs
gcc/c-family/c-warn.o differs
gcc/value-range-storage.o differs
gcc/tree-eh.o differs
gcc/gimple-match-1.o differs
gcc/gimple-predicate-analysis.o differs
gcc/tree-ssa-loop-ch.o differs
gcc/tree-if-conv.o differs
gcc/ordered-hash-map-tests.o differs
gcc/tree-ssa-strlen.o differs
gcc/gimple-streamer-out.o differs
gcc/tree-dfa.o differs
gcc/tree-predcom.o differs
gcc/early-remat.o differs
gcc/tree-ssa-ifcombine.o differs
gcc/ipa-inline.o differs
gcc/gimple-loop-interchange.o differs
gcc/ipa-cp.o differs
gcc/cp/cp-gimplify.o differs
gcc/cp/decl.o differs
gcc/cp/parser.o differs
gcc/cp/semantics.o differs
gcc/cp/constraint.o differs
gcc/cp/tree.o differs
gcc/cp/error.o differs
gcc/cp/typeck.o differs
gcc/cp/decl2.o differs
gcc/cp/rtti.o differs
gcc/expmed.o differs
gcc/sanopt.o differs
gcc/trans-mem.o differs
gcc/c/c-decl.o differs
gcc/c/c-parser.o differs
gcc/targhooks.o differs
gcc/tree-ssa-threadbackward.o differs
gcc/gimple.o differs
gcc/ipa-prop.o differs
gcc/tree-ssa-sccvn.o differs
gcc/range-op.o differs
libcody/server.o differs
libcpp/files.o differs
libcpp/macro.o differs
libcpp/lex.o differs
libiberty/pic/simple-object-mach-o.o differs
libiberty/simple-object.o differs
libiberty/simple-object-mach-o.o differs
make[2]: *** [Makefile:22598: compare] Error 1
make[1]: *** [Makefile:22578: stage3-bubble] Error 2
make: *** [Makefile:22652: bootstrap-lean] Error 2

I'll include the stage 2 and 3 spellcheck.o files as well.

I can provide a clean qemu-user image to aid in testing this if it is helpful
so it can be reproduced on a x86_64 machine.