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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/99930] Failure to optimize floating point -abs(x) in nontrivial code at -O2/3 Date: Tue, 06 Apr 2021 11:57:05 +0000 [thread overview] Message-ID: <bug-99930-4-NioTV3VrEp@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-99930-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99930 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2021-04-06 Status|UNCONFIRMED |NEW Ever confirmed|0 |1 Target| |x86_64-*-* Component|target |rtl-optimization --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- Confirmed. At -O1 Trying 10 -> 12: 10: {r91:SF=abs(r92:SF);use [`*.LC0'];clobber flags:CC;} REG_UNUSED flags:CC REG_DEAD r92:SF 12: {r94:SF=-r91:SF;use r95:V4SF;clobber flags:CC;} REG_DEAD r95:V4SF REG_DEAD r91:SF REG_UNUSED flags:CC Failed to match this instruction: (parallel [ (set (reg:SF 94) (neg:SF (abs:SF (reg:SF 92 [ *n_9(D) ])))) (use (reg:V4SF 95)) (clobber (reg:CC 17 flags)) ]) Successfully matched this instruction: (parallel [ (set (reg:SF 94) (neg:SF (abs:SF (reg:SF 92 [ *n_9(D) ])))) (use (reg:V4SF 95)) ]) allowing combination of insns 10 and 12 original costs 4 + 4 = 8 replacement cost 8 but with -O2: Trying 10 -> 12: 10: {r91:SF=abs(r92:SF);use r93:V4SF;clobber flags:CC;} REG_DEAD r92:SF REG_UNUSED flags:CC 12: {r94:SF=-r91:SF;use r95:V4SF;clobber flags:CC;} REG_DEAD r91:SF REG_UNUSED flags:CC Can't combine i2 into i3 we're later trying Trying 10, 12 -> 13: 10: {r91:SF=abs(r92:SF);use r93:V4SF;clobber flags:CC;} REG_DEAD r92:SF REG_UNUSED flags:CC 12: {r94:SF=-r91:SF;use r95:V4SF;clobber flags:CC;} REG_DEAD r91:SF REG_UNUSED flags:CC 13: flags:CCFP=cmp(r90:SF,r94:SF) REG_DEAD r94:SF Failed to match this instruction: (set (reg:CCFP 17 flags) (compare:CCFP (neg:SF (abs:SF (reg:SF 92 [ *n_9(D) ]))) (reg/v:SF 90 [ m ]))) Failed to match this instruction: (set (reg:SF 94) (abs:SF (reg:SF 92 [ *n_9(D) ])))
next prev parent reply other threads:[~2021-04-06 11:57 UTC|newest] Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-06 10:38 [Bug target/99930] New: " core13 at gmx dot net 2021-04-06 11:57 ` rguenth at gcc dot gnu.org [this message] 2021-04-06 12:00 ` [Bug rtl-optimization/99930] " rguenth at gcc dot gnu.org 2021-04-06 17:31 ` segher at gcc dot gnu.org 2021-04-07 10:04 ` jakub at gcc dot gnu.org 2021-04-07 10:06 ` jakub at gcc dot gnu.org 2021-04-07 10:14 ` ubizjak at gmail dot com 2021-04-07 10:27 ` crazylht at gmail dot com 2021-04-07 16:32 ` segher at gcc dot gnu.org 2021-04-08 9:48 ` crazylht at gmail dot com 2021-04-08 22:46 ` segher at gcc dot gnu.org 2021-07-25 1:30 ` pinskia at gcc dot gnu.org 2023-12-24 23:16 ` [Bug middle-end/99930] " pinskia at gcc dot gnu.org
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