RISC-V: Always register vector built-in functions during LTO [PR110812]

Previously, vector built-in functions were not properly registered during
the LTO pipeline, causing link failures when vector intrinsics were used
in LTO builds with mixed architecture options.  This patch ensures all
vector built-in functions are always registered during LTO compilation.

The key changes include:
- Moving pragma intrinsic flag manipulation from riscv-c.cc to
  riscv-vector-builtins.cc for better encapsulation
- Registering all vector built-in functions regardless of current ISA
  extensions, deferring the actual extension checking to expansion time
- Adding proper support for built-in type registration during LTO

This approach is safe because we already perform extension requirement
checking at expansion time.  The trade-off is a slight increase in
bootstrap time for LTO builds due to registering more built-in functions.

	PR target/110812

gcc/ChangeLog:

	* config/riscv/riscv-c.cc (pragma_intrinsic_flags): Remove struct.
	(riscv_pragma_intrinsic_flags_pollute): Remove function.
	(riscv_pragma_intrinsic_flags_restore): Remove function.
	(riscv_pragma_intrinsic): Simplify to only call handle_pragma_vector.
	* config/riscv/riscv-vector-builtins.cc (pragma_intrinsic_flags):
	Move struct definition here from riscv-c.cc.
	(riscv_pragma_intrinsic_flags_pollute): Move and adapt from
	riscv-c.cc, add zvfbfmin, zvfhmin and vector_elen_bf_16 support.
	(riscv_pragma_intrinsic_flags_restore): Move from riscv-c.cc.
	(rvv_switcher::rvv_switcher): Add pollute_flags parameter to
	control flag manipulation.
	(rvv_switcher::~rvv_switcher): Restore flags conditionally.
	(register_builtin_types): Use rvv_switcher without polluting flags.
	(get_required_extensions): Remove function.
	(check_required_extensions): Simplify to only check type validity.
	(function_instance::function_returns_void_p): Move implementation
	from header.
	(function_builder::add_function): Register placeholder for LTO.
	(init_builtins): Simplify and handle LTO case.
	(reinit_builtins): Remove function.
	(handle_pragma_vector): Remove extension checking.
	* config/riscv/riscv-vector-builtins.h
	(function_instance::function_returns_void_p): Add declaration.
	(function_call_info::function_returns_void_p): Remove inline
	implementation.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/lto/pr110812_0.c: New test.
	* gcc.target/riscv/lto/pr110812_1.c: New test.
	* gcc.target/riscv/lto/riscv-lto.exp: New test driver.
	* gcc.target/riscv/lto/riscv_vector.h: New header wrapper.

0 files changed, 0 insertions, 0 deletions