Re: [PATCH 1/2] genopinit: Distribute generated code across multiple files

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