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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/105175] [12 Regression] Pointless warning about missed vector optimization Date: Wed, 06 Apr 2022 08:17:21 +0000 [thread overview] Message-ID: <bug-105175-4-tDj3RaNXBC@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-105175-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105175 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Component|rtl-optimization |tree-optimization Last reconfirmed| |2022-04-06 Target Milestone|--- |12.0 Target| |x86_64-*-* Status|UNCONFIRMED |ASSIGNED Keywords| |diagnostic, | |missed-optimization Ever confirmed|0 |1 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- I think the issue is that the vectorizer generates <bb 2> [local count: 1073741824]: + vect__1.5_8 = MEM <vector(2) unsigned int> [(unsigned int *)&qemuMigrationCookieGetPersistent_mig]; + vect__2.6_9 = vect__1.5_8 & { 1, 1 }; _1 = qemuMigrationCookieGetPersistent_mig.flags; _2 = _1 & 1; - qemuMigrationCookieGetPersistent_mig.flags = _2; _3 = qemuMigrationCookieGetPersistent_mig.flagsMandatory; _4 = _3 & 1; - qemuMigrationCookieGetPersistent_mig.flagsMandatory = _4; + MEM <vector(2) unsigned int> [(unsigned int *)&qemuMigrationCookieGetPersistent_mig] = vect__2.6_9; but appearantly it does not check availability of the bitwise AND V2SImode operation. vector lowering recognizes this missing operation and lowers it to + long unsigned int _6; + long unsigned int _7; + vector(2) unsigned int _11; <bb 2> [local count: 1073741824]: vect__1.5_8 = MEM <vector(2) unsigned int> [(unsigned int *)&qemuMigrationCookieGetPersistent_mig]; - vect__2.6_9 = vect__1.5_8 & { 1, 1 }; + _7 = VIEW_CONVERT_EXPR<long unsigned int>(vect__1.5_8); + _6 = _7 & 4294967297; + _11 = VIEW_CONVERT_EXPR<vector(2) unsigned int>(_6); + vect__2.6_9 = _11; _maybe_ V2SImode is also a real thing now even with -mno-sse, but the AND is cut out (or not implemented). That is, this is probably a vectorizer missed target check.
next prev parent reply other threads:[~2022-04-06 8:17 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-04-06 7:00 [Bug rtl-optimization/105175] New: " krebbel at gcc dot gnu.org 2022-04-06 8:17 ` rguenth at gcc dot gnu.org [this message] 2022-04-06 8:30 ` [Bug tree-optimization/105175] " krebbel at gcc dot gnu.org 2022-04-06 8:49 ` rguenth at gcc dot gnu.org 2022-04-06 9:17 ` rguenth at gcc dot gnu.org 2022-04-08 6:34 ` cvs-commit at gcc dot gnu.org 2022-04-08 6:35 ` rguenth at gcc dot gnu.org
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