[Bug target/112330] [14 Regression] LoongArch: Outputted .align directive may trigger assembler error with GAS 2.41

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112330

--- Comment #16 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Xi Ruoyao <xry111@gcc.gnu.org>:

https://gcc.gnu.org/g:fe23a2ff1f5072559552be0e41ab55bf72f5c79f

commit r14-5434-gfe23a2ff1f5072559552be0e41ab55bf72f5c79f
Author: Xi Ruoyao <xry111@xry111.site>
Date:   Fri Nov 3 21:19:59 2023 +0800

    LoongArch: Disable relaxation if the assembler don't support conditional
branch relaxation [PR112330]

    As the commit message of r14-4674 has indicated, if the assembler does
    not support conditional branch relaxation, a relocation overflow may
    happen on conditional branches when relaxation is enabled because the
    number of NOP instructions inserted by the assembler will be more than
    the number estimated by GCC.

    To work around this issue, disable relaxation by default if the
    assembler is detected incapable to perform conditional branch relaxation
    at GCC build time.  We also need to pass -mno-relax to the assembler to
    really disable relaxation.  But, if the assembler does not support
    -mrelax option at all, we should not pass -mno-relax to the assembler or
    it will immediately error out.  Also handle this with the build time
    assembler capability probing, and add a pair of options
    -m[no-]pass-mrelax-to-as to allow using a different assembler from the
    build-time one.

    With this change, if GCC is built with GAS 2.41, relaxation will be
    disabled by default.  So the default value of -mexplicit-relocs= is also
    changed to 'always' if -mno-relax is specified or implied by the
    build-time default, because using assembler macros for symbol addresses
    produces no benefit when relaxation is disabled.

    gcc/ChangeLog:

            PR target/112330
            * config/loongarch/genopts/loongarch.opt.in: Add
            -m[no]-pass-relax-to-as.  Change the default of -m[no]-relax to
            account conditional branch relaxation support status.
            * config/loongarch/loongarch.opt: Regenerate.
            * configure.ac (gcc_cv_as_loongarch_cond_branch_relax): Check if
            the assembler supports conditional branch relaxation.
            * configure: Regenerate.
            * config.in: Regenerate.  Note that there are some unrelated
            changes introduced by r14-5424 (which does not contain a
            config.in regeneration).
            * config/loongarch/loongarch-opts.h
            (HAVE_AS_COND_BRANCH_RELAXATION): Define to 0 if not defined.
            * config/loongarch/loongarch-driver.h (ASM_MRELAX_DEFAULT):
            Define.
            (ASM_MRELAX_SPEC): Define.
            (ASM_SPEC): Use ASM_MRELAX_SPEC instead of "%{mno-relax}".
            * config/loongarch/loongarch.cc: Take the setting of
            -m[no-]relax into account when determining the default of
            -mexplicit-relocs=.
            * doc/invoke.texi: Document -m[no-]relax and
            -m[no-]pass-mrelax-to-as for LoongArch.  Update the default
            value of -mexplicit-relocs=.