https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82356
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2021-08-14 00:00:00 |2021-8-24
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
With -O3 -fno-move-loop-invariants -fno-gcse
We get
Trying 38, 34 -> 39:
38: r160:V8HI=[`*.LC0']
REG_EQUAL const_vector
34: r154:V8HI=r153:V8HI 0>>0x8
REG_DEAD r153:V8HI
39: r158:V8HI=r160:V8HI&r154:V8HI
REG_DEAD r154:V8HI
Failed to match this instruction:
(parallel [
(set (reg:V8HI 158)
(and:V8HI (lshiftrt:V8HI (reg:V8HI 153 [ vect__1.12 ])
(const_int 8 [0x8]))
(const_vector:V8HI [
(const_int 255 [0xff]) repeated x8
])))
(set (reg:V8HI 160)
(mem/u/c:V8HI (symbol_ref/u:DI ("*.LC0") [flags 0x2]) [0 S16
A128]))
])
Failed to match this instruction:
(parallel [
(set (reg:V8HI 158)
(and:V8HI (lshiftrt:V8HI (reg:V8HI 153 [ vect__1.12 ])
(const_int 8 [0x8]))
(const_vector:V8HI [
(const_int 255 [0xff]) repeated x8
])))
(set (reg:V8HI 160)
(mem/u/c:V8HI (symbol_ref/u:DI ("*.LC0") [flags 0x2]) [0 S16
A128]))
])
Successfully matched this instruction:
(set (reg:V8HI 160)
(mem/u/c:V8HI (symbol_ref/u:DI ("*.LC0") [flags 0x2]) [0 S16 A128]))
Failed to match this instruction:
(set (reg:V8HI 158)
(and:V8HI (lshiftrt:V8HI (reg:V8HI 153 [ vect__1.12 ])
(const_int 8 [0x8]))
(const_vector:V8HI [
(const_int 255 [0xff]) repeated x8
])))
Which we don't recongize the and part is not needed.
Also since we don't emit REG_EQUAL when using vector_csts, we needed to use
"-fno-move-loop-invariants -fno-gcse ".
