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From: "bonzini at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/18008] [4.0 Regression] Duplicate mask on bitfield insertion Date: Sat, 22 Jan 2005 10:05:00 -0000 [thread overview] Message-ID: <20050122100448.3564.qmail@sourceware.org> (raw) In-Reply-To: <20041015091714.18008.nathan@gcc.gnu.org> ------- Additional Comments From bonzini at gcc dot gnu dot org 2005-01-22 10:04 ------- Combine ought to merge these two (insn 13 11 14 1 (parallel [ (set (reg:QI 60) (and:QI (subreg:QI (reg/v:SI 59 [ v ]) 0) (const_int 3 [0x3]))) (clobber (reg:CC 17 flags)) ]) -1 (nil) (nil)) (insn 15 14 16 1 (parallel [ (set (reg:SI 62) (zero_extend:SI (reg:QI 60))) (clobber (reg:CC 17 flags)) ]) -1 (nil) (nil)) into (insn 15 14 16 1 (parallel [ (set (reg:SI 62) (zero_extend:SI (and:QI (subreg:QI (reg/v:SI 59 [ v ]) 0) (const_int 3 [0x3])))) (clobber (reg:CC 17 flags)) ]) -1 (nil) (nil)) which can be simplified via the expand_compound_operation machinery to (insn 15 14 16 1 (parallel [ (set (reg:SI 62) (and:SI (reg/v:SI 59 [ v ]) (const_int 3 [0x3]))) (clobber (reg:CC 17 flags)) ]) -1 (nil) (nil)) and the set of (reg:SI 63) from (and:SI (reg:SI 62) (const_int 3)) should be taken care of by the nonzero_bits stuff. So it's feasible to have combine fix it, at least. Hum, but maybe the clobber is messing up combine? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18008
next prev parent reply other threads:[~2005-01-22 10:05 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2004-10-15 9:17 [Bug c/18008] New: " nathan at gcc dot gnu dot org 2004-10-15 12:46 ` [Bug middle-end/18008] [4.0 Regression] " pinskia at gcc dot gnu dot org 2004-10-15 15:03 ` bangerth at dealii dot org 2004-10-15 16:42 ` kazu at cs dot umass dot edu 2004-10-15 16:55 ` kazu at cs dot umass dot edu 2004-10-15 21:18 ` kazu at cs dot umass dot edu 2004-10-16 3:46 ` kazu at cs dot umass dot edu 2004-10-16 3:50 ` kazu at cs dot umass dot edu 2004-10-16 4:05 ` pinskia at gcc dot gnu dot org 2004-10-17 19:02 ` roger at eyesopen dot com 2004-12-23 16:05 ` pinskia at gcc dot gnu dot org 2005-01-22 10:05 ` bonzini at gcc dot gnu dot org [this message] 2005-01-26 1:55 ` steven at gcc dot gnu dot org 2005-01-26 2:13 ` steven at gcc dot gnu dot org 2005-01-26 18:11 ` rth at gcc dot gnu dot org 2005-01-26 20:30 ` cvs-commit at gcc dot gnu dot org 2005-01-26 23:18 ` cvs-commit at gcc dot gnu dot org 2005-01-27 0:08 ` cvs-commit at gcc dot gnu dot org 2005-01-27 0:13 ` rth at gcc dot gnu dot org
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