[Bug target/81268] [avr] Support __gcc_isr pseudo-instruction for more efficient ISR prologues

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81268

--- Comment #1 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Author: gjl
Date: Mon Jul 10 09:49:18 2017
New Revision: 250093

URL: https://gcc.gnu.org/viewcvs?rev=250093&root=gcc&view=rev
Log:
gcc/
        Better ISR prologues by supporting GASes __gcc_isr pseudo insn.
        PR target/20296
        PR target/81268
        * configure.ac [target=avr]: Add GAS check for -mgcc-isr.
        (HAVE_AS_AVR_MGCCISR_OPTION):  If so, AC_DEFINE it.
        * config.in: Regenerate.
        * configure: Regenerate.
        * doc/extend.texi (AVR Function Attributes) <no_gccisr>: Document it.
        * doc/invoke.texi (AVR Options) <-mgas-isr-prologues>: Document it.
        * config/avr/avr.opt (-mgas-isr-prologues): New option and...
        (TARGET_GASISR_PROLOGUES): ...target mask.
        * common/config/avr/avr-common.c
        (avr_option_optimization_table) [OPT_LEVELS_1_PLUS_NOT_DEBUG]:
        Set -mgas-isr-prologues.
        * config/avr/avr-passes.def (avr_pass_pre_proep): Add
        INSERT_PASS_BEFORE for it.
        * config/avr/avr-protos.h (make_avr_pass_pre_proep): New proto.
        * config/avr/avr.c (avr_option_override)
        [!HAVE_AS_AVR_MGCCISR_OPTION]: Unset TARGET_GASISR_PROLOGUES.
        (avr_no_gccisr_function_p, avr_hregs_split_reg): New static functions.
        (avr_attribute_table) <no_gccisr>: Add new function attribute.
        (avr_set_current_function) <is_no_gccisr>: Init machine field.
        (avr_pass_data_pre_proep, avr_pass_pre_proep): New pass data
        and rtl_opt_pass.
        (make_avr_pass_pre_proep): New function.
        (emit_push_sfr) <treg>: Add argument to function and use it
        instead of TMP_REG.
        (avr_expand_prologue) [machine->gasisr.maybe]: Emit gasisr insn
        and set machine->gasisr.yes.
        (avr_expand_epilogue) [machine->gasisr.yes]: Similar.
        (avr_asm_function_end_prologue) [machine->gasisr.yes]: Add
        __gcc_isr.n_pushed to .L__stack_usage.
        (TARGET_ASM_FINAL_POSTSCAN_INSN): Define to...
        (avr_asm_final_postscan_insn): ...this new static function.
        * config/avr/avr.h (machine_function)
        <is_no_gccisr, use_L__stack_usage>: New fields.
        <gasisr, gasisr.yes, gasisr.maybe, gasisr.regno>: New fields.
        * config/avr/avr.md (UNSPECV_GASISR): Add unspecv enum.
        (GASISR_Prologue, GASISR_Epilogue, GASISR_Done): New define_constants.
        (gasisr, *gasisr): New expander and insn.
        * config/avr/gen-avr-mmcu-specs.c (print_mcu)
        [HAVE_AS_AVR_MGCCISR_OPTION]: Print asm_gccisr spec.
        * config/avr/specs.h (ASM_SPEC) <asm_gccisr>: Add sub spec.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/common/config/avr/avr-common.c
    trunk/gcc/config.in
    trunk/gcc/config/avr/avr-passes.def
    trunk/gcc/config/avr/avr-protos.h
    trunk/gcc/config/avr/avr.c
    trunk/gcc/config/avr/avr.h
    trunk/gcc/config/avr/avr.md
    trunk/gcc/config/avr/avr.opt
    trunk/gcc/config/avr/gen-avr-mmcu-specs.c
    trunk/gcc/config/avr/specs.h
    trunk/gcc/configure
    trunk/gcc/configure.ac
    trunk/gcc/doc/extend.texi
    trunk/gcc/doc/invoke.texi
    trunk/gcc/testsuite/gcc.target/avr/isr-test.h