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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/85730] complex code for modifying lowest byte in a 4-byte vector Date: Mon, 04 Oct 2021 09:54:37 +0000 [thread overview] Message-ID: <bug-85730-4-bce0ERf4i0@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-85730-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85730 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |segher at gcc dot gnu.org --- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> --- The GIMPLE IL is now using BIT_INSERT_EXPRs consistently for all cases and combine does Trying 8 -> 11: 8: {r90:SI=r89:SI<<0x1;clobber flags:CC;} REG_DEAD r89:SI REG_UNUSED flags:CC 11: strict_low_part(r92:V4QI#0)=r90:SI#0 REG_DEAD r90:SI Failed to match this instruction: (set (strict_low_part (subreg:QI (reg:V4QI 92 [ v ]) 0)) (ashift:QI (subreg:QI (reg:SI 89 [ v ]) 0) (const_int 1 [0x1]))) where it fails to try (add:QI (subreg...) (subreg...)) instead of the shift by 1. Not sure whether targets should have a special-case pattern here or whether that's for combine to un-canonicalize it?
next prev parent reply other threads:[~2021-10-04 9:54 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-85730-4@http.gcc.gnu.org/bugzilla/> 2021-10-04 3:02 ` gabravier at gmail dot com 2021-10-04 8:47 ` zsojka at seznam dot cz 2021-10-04 9:04 ` gabravier at gmail dot com 2021-10-04 9:54 ` rguenth at gcc dot gnu.org [this message] 2021-10-04 11:31 ` ubizjak at gmail dot com 2021-10-04 16:13 ` segher at gcc dot gnu.org 2021-10-07 11:51 ` ubizjak at gmail dot com 2021-10-08 9:36 ` ubizjak at gmail dot com 2021-10-12 16:21 ` cvs-commit at gcc dot gnu.org
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