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

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).

Jeff