https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101529
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2021-07-20
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
-Og:
_13 = BIT_FIELD_REF <_12, 64, 0>;
_4 = VEC_PERM_EXPR <_13, { 0, 0, 0, 0, 0, 0, 0, 0 }, { 3, 9, 10, 11, 12, 13,
14, 15 }>;
_14 = BIT_FIELD_REF <_4, 8, 0>;
vs -O2:
_14 = BIT_FIELD_REF <_12, 8, 24>;
Huh:
;; _4 = VEC_PERM_EXPR <_13, { 0, 0, 0, 0, 0, 0, 0, 0 }, { 3, 9, 10, 11, 12, 13,
14, 15 }>;
(insn 16 15 17 (set (reg:V8QI 95 [ _4 ])
(vec_select:V8QI (reg:V16QI 98 [ _12 ])
(parallel [
(const_int 0 [0])
(const_int 1 [0x1])
(const_int 2 [0x2])
(const_int 3 [0x3])
(const_int 4 [0x4])
(const_int 5 [0x5])
(const_int 6 [0x6])
(const_int 7 [0x7])
]))) "t5.c":11:10 -1
(nil))
;;; Select the lower part aka _13
(insn 17 16 18 (set (reg:V8QI 112)
(const_vector:V8QI [
(const_int 0 [0]) repeated x8
])) "t5.c":11:10 -1
(nil))
(insn 18 17 19 (set (reg:V8QI 95 [ _4 ])
(reg:V8QI 112)) "t5.c":11:10 -1
(nil))
;;; BUT reuse 95/_4 for the zero constant!!!!!!!!!!!!!!!
(insn 19 18 0 (set (reg:V8QI 95 [ _4 ])
(vec_merge:V8QI (vec_duplicate:V8QI (vec_select:QI (reg:V8QI 95 [ _4 ])
(parallel [
(const_int 3 [0x3])
])))
(reg:V8QI 95 [ _4 ])
(const_int 1 [0x1]))) "t5.c":11:10 -1
(nil))
