[Bug target/55181] [10/11/12/13/14 Regression] Expensive shift loop where a bit-testing instruction could be used
pinskia at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Fri May 19 23:13:35 GMT 2023
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55181
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot gnu.org
Status|NEW |ASSIGNED
--- Comment #26 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So I guess this is mine too.
With my patches I created to improve PR 109907 (attached there), the initial
RTL now looks like:
;; _9 = (unsigned char) _8;
(insn 6 5 0 (set (reg/v:QI 46 [ <retval> ])
(zero_extract:QI (subreg:QI (reg/v:SI 47 [ number ]) 3)
(const_int 1 [0x1])
(const_int 5 [0x5]))) "t2.c":4:6 -1
(nil))
Where it was before:
;; _9 = (unsigned char) _8;
(insn 6 5 7 (set (reg:SI 48)
(lshiftrt:SI (reg/v:SI 47 [ number ])
(const_int 29 [0x1d]))) "t2.c":4:6 -1
(nil))
(insn 7 6 0 (set (reg/v:QI 46 [ <retval> ])
(and:QI (subreg:QI (reg:SI 48) 0)
(const_int 1 [0x1]))) "t2.c":4:6 -1
(nil))
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