On 7/23/2026 7:20 AM, [email protected] wrote:
From: Kyrylo Tkachov <[email protected]>

insn-opinit.cc contains large generated initialization functions with
thousands of target-feature expressions.  The single file is among the
slowest objects in every AArch64 bootstrap stage.

Teach genopinit to accept repeatable -O output options, following genemit and
genrecog.  Reuse the existing --with-insnemit-partitions count, while
preserving the default init-opinit.c output and -cFILE interface when -O is not
used.  Collect and validate all output names before opening them, rejecting
duplicates, resolvable aliases, header collisions, and incompatible -c and -O
options.

Keep shared lookup code and all helper declarations in the first output, then
place helper definitions in the shortest output.  One-file output retains the
historical static helper names.  Split output uses generator-private external
names for cross-file references.

With the default ten AArch64 partitions, the largest part compiles about 90%
faster than the original single object.

Bootstrapped and tested on aarch64-none-linux-gnu and x86_64-linux.
Ok for trunk?
Thanks,
Kyrill

gcc/ChangeLog:

        * Makefile.in (INSNOPINIT_SPLITS_SEQ, INSNOPINIT_SEQ_SRC)
        (INSNOPINIT_SEQ_TMP, INSNOPINIT_SEQ_O): New variables.
        (OBJS): Replace insn-opinit.o with $(INSNOPINIT_SEQ_O).
        (MOSTLYCLEANFILES): Add $(INSNOPINIT_SEQ_SRC), retaining the legacy
        unnumbered source for cleanup.
        (s-opinit): Generate and move numbered insn-opinit-N.cc files.  Stop if
        moving an output fails.
        * configure.ac (--with-insnemit-partitions): Mention genopinit outputs.
        * configure: Regenerate.
        * genopinit.cc (source_file_option, output_file_names, output_files):
        New variables.
        (handle_arg): Record and validate repeatable -O output names.
        (main): Validate all output modes before opening files.  Preserve static
        helper linkage for one output and distribute private split helpers.

Signed-off-by: Kyrylo Tkachov <[email protected]>
It'll be interesting to see if this improves the RISC-V build times too.  Robin fixed the worst of the offenders a while back, but we've got daily build data and if there's a meaningful improvement we should be able to see it.

The only concern is the INSNOPINIT_SPLITS_SEQ is slightly different than the other _SEQ variables.    The others use:

MATCH_SPLITS_SEQ = $(wordlist 1,$(NUM_MATCH_SPLITS),$(one_to_9999))
INSNEMIT_SPLITS_SEQ = $(wordlist 1,$(NUM_INSNEMIT_SPLITS),$(one_to_9999))
INSNRECOG_SPLITS_SEQ = $(wordlist 1,$(NUM_INSNEMIT_SPLITS),$(one_to_9999))

Is there a reason you didn't use that form?

jeff

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