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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/108840] Aarch64 doesn't optimize away shift counter masking Date: Fri, 17 Feb 2023 18:08:44 +0000 [thread overview] Message-ID: <bug-108840-4-RzR5BQt6Qr@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-108840-4@http.gcc.gnu.org/bugzilla/> 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.
next prev parent reply other threads:[~2023-02-17 18:08 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-02-17 17:59 [Bug target/108840] New: " jakub at gcc dot gnu.org 2023-02-17 18:08 ` pinskia at gcc dot gnu.org [this message] 2023-02-21 12:24 ` [Bug target/108840] " ktkachov at gcc dot gnu.org 2023-02-24 15:37 ` ktkachov at gcc dot gnu.org 2023-04-19 8:35 ` cvs-commit at gcc dot gnu.org 2023-04-19 8:37 ` ktkachov at gcc dot gnu.org
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