https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108840
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2023-02-17
See Also|https://gcc.gnu.org/bugzill |
|a/show_bug.cgi?id=91202 |
Status|UNCONFIRMED |NEW
Keywords| |missed-optimization
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed:
Trying 8 -> 10:
8: r93:SI=r108:SI&0x1f
REG_DEAD r108:SI
10: r101:SI=r102:SI<<r93:SI#0
REG_DEAD r102:SI
Failed to match this instruction:
(parallel [
(set (reg:SI 101)
(ashift:SI (reg:SI 102 [ *x_9(D) ])
(subreg:QI (and:SI (reg:SI 108)
(const_int 31 [0x1f])) 0)))
(set (reg:SI 93 [ _2 ])
(and:SI (reg:SI 108)
(const_int 31 [0x1f])))
])
Failed to match this instruction:
(parallel [
(set (reg:SI 101)
(ashift:SI (reg:SI 102 [ *x_9(D) ])
(subreg:QI (and:SI (reg:SI 108)
(const_int 31 [0x1f])) 0)))
(set (reg:SI 93 [ _2 ])
(and:SI (reg:SI 108)
(const_int 31 [0x1f])))
])
Successfully matched this instruction:
(set (reg:SI 93 [ _2 ])
(and:SI (reg:SI 108)
(const_int 31 [0x1f])))
Successfully matched this instruction:
(set (reg:SI 101)
(ashift:SI (reg:SI 102 [ *x_9(D) ])
(subreg:QI (and:SI (reg:SI 108)
(const_int 31 [0x1f])) 0)))
rejecting combination of insns 8 and 10
original costs 4 + 4 = 8
replacement costs 4 + 8 = 12
The replacement cost should be still 8.
