i386: Save/restore recog_data in ix86_vector_duplicate_value [PR106577]

i386: Save/restore recog_data in ix86_vector_duplicate_value [PR106577]

On Tue, Aug 16, 2022 at 09:14:06AM +0100, Richard Sandiford via Gcc-patches wrote:
> IMO the correct low-effort fix is to save and restore recog_data
> in ix86_vector_duplicate_value.  It's a relatively big copy,
> but the current code is pretty wasteful anyway (allocating at
> least a new SET and INSN for every query).  Compared to the
> overhead of doing that, a copy to and from the stack shouldn't
> be too bad.

The following patch does that.
It isn't the first spot in the compiler that does that, not even the first
spot in the i386 backend.
In i386-expand.cc beyond these 2 recog_memoized calls there is one in
expand_vselect, but I think it is unlikely we'd run into these issues trying
to expand new permutations from splitters.

2022-12-02  Jakub Jelinek  <jakub@redhat.com>

	PR target/106577
	* config/i386/i386-expand.cc (ix86_vector_duplicate_value): Save/restore
	recog_data around recog_memoized calls.

	* gcc.target/i386/pr106577.c: New test.