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.
---
gcc/common/config/riscv/riscv-common.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/common/config/riscv/riscv-common.cc
b/gcc/common/config/riscv/riscv-common.cc
index 2d56ba59f0e..6bbbacab8df 100644
--- a/gcc/common/config/riscv/riscv-common.cc
+++ b/gcc/common/config/riscv/riscv-common.cc
@@ -135,7 +135,7 @@ public:
/* Return true if any change. */
bool apply_implied_ext (riscv_subset_list *subset_list) const;
- const std::vector<riscv_implied_info_t> implied_exts () const
+ const std::vector<riscv_implied_info_t> &implied_exts () const
{
return m_implied_exts;
}
--
2.52.0
