Re: [PATCH] RISC-V: Return implied_exts by const refer ence

> On 7/22/2026 5:50 AM, Jin Ma wrote:
> > riscv_ext_info_t::implied_exts() returns its std::vector member by
> > value, but all three callers (check_implied_ext, handle_combine_ext,
> > riscv_minimal_hwprobe_feature_bits) only iterate over the result and
> > never need ownership.  Every invocation therefore copies the entire
> > implied-extension vector.  During option parsing this runs once per
> > compiled source file; at -O0 the optimisation passes are skipped so
> > option-parsing overhead dominates, causing a 6.7% compile-time
> > regression on CSIBE -O0 benchmarks.
> >
> > Return a const reference instead.  The underlying m_implied_exts
> > member lives in a static global map entry and outlives every caller,
> > so no dangling-reference risk exists.
> >
> > gcc/ChangeLog:
> >
> >  * common/config/riscv/riscv-common.cc
> >  (riscv_ext_info_t::implied_exts): Return const reference
> >  instead of by-value copy.
> This is OK assuming it has gone through the usual testing (no testing 
> was mentioned).

Hi Jeff,

I did omit the testing information from the original email. Sorry.

The patch passed my local CI with no new failures.  Since this change
affects a common code path exercised by most tests, I do not think an
additional test case is necessary.

OK for trunk?

Thanks,
Jin