https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119368
--- Comment #2 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
On this combiner fails to match:
Failed to match this instruction:
(set (subreg:V4SI (reg:V2DI 101 [ <retval> ]) 0)
(sign_extend:V4SI (vec_select:V4HI (mem:V8HI (reg:DI 106) [0 *x_3(D)+0 S16
A128])
(parallel [
(const_int 0 [0])
(const_int 1 [0x1])
(const_int 2 [0x2])
(const_int 3 [0x3])
]))))
which is
(define_insn "sse4_1_<code>v4hiv4si2<mask_name>"
[(set (match_operand:V4SI 0 "register_operand" "=Yr,*x,v")
(any_extend:V4SI
(vec_select:V4HI
(match_operand:V8HI 1 "register_operand" "Yr,*x,v")
(parallel [(const_int 0) (const_int 1)
(const_int 2) (const_int 3)]))))]
"TARGET_SSE4_1 && <mask_avx512vl_condition>"
"%vpmov<extsuffix>wd\t{%1, %0<mask_operand2>|%0<mask_operand2>, %1}"
[(set_attr "isa" "noavx,noavx,avx")
(set_attr "type" "ssemov")
(set_attr "prefix_extra" "1")
(set_attr "prefix" "orig,orig,maybe_evex")
(set_attr "mode" "TI")])
(define_insn "*sse4_1_<code>v4hiv4si2<mask_name>_1"
[(set (match_operand:V4SI 0 "register_operand" "=Yr,*x,v")
(any_extend:V4SI
(match_operand:V4HI 1 "memory_operand" "jm,jm,m")))]
"TARGET_SSE4_1 && <mask_avx512vl_condition>"
"%vpmov<extsuffix>wd\t{%1, %0<mask_operand2>|%0<mask_operand2>, %1}"
[(set_attr "isa" "noavx,noavx,avx")
(set_attr "addr" "gpr16,gpr16,*")
(set_attr "type" "ssemov")
(set_attr "prefix_extra" "1")
(set_attr "prefix" "orig,orig,maybe_evex")
(set_attr "mode" "TI")])
So it seems sse.md expects combiner to be able to simplify the vec_select of
mem into shorter mem, while combiner doesn't do that?
