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From: "roger at nextmovesoftware dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/106594] [13 Regression] sign-extensions no longer merged into addressing mode Date: Sun, 05 Mar 2023 12:00:17 +0000 [thread overview] Message-ID: <bug-106594-4-xMr8Jng3HL@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-106594-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106594 --- Comment #15 from Roger Sayle <roger at nextmovesoftware dot com> --- An example of combine's temporary lapses of sanity can be seen on powerpc: Trying 14 -> 15: 14: %3:SI=sign_extend(r128:SI#2)*sign_extend(r127:SI#2) REG_DEAD r128:SI REG_DEAD r127:SI 15: use %3:SI Failed to match this instruction: (parallel [ (use (mult:SI (ashiftrt:SI (ashift:SI (reg:SI 128) (const_int 16 [0x10])) (const_int 16 [0x10])) (ashiftrt:SI (ashift:SI (reg:SI 127) (const_int 16 [0x10])) (const_int 16 [0x10])))) (set (reg/i:SI 3 3) (mult:SI (sign_extend:SI (subreg:HI (reg:SI 128) 2)) (sign_extend:SI (subreg:HI (reg:SI 127) 2)))) ]) with the proposed patch, we now see: Trying 14 -> 15: 14: %3:SI=sign_extend(r128:SI#2)*sign_extend(r127:SI#2) REG_DEAD r128:SI REG_DEAD r127:SI 15: use %3:SI Failed to match this instruction: (parallel [ (use (mult:SI (sign_extend:SI (subreg:HI (reg:SI 128) 2)) (sign_extend:SI (subreg:HI (reg:SI 127) 2)))) (set (reg/i:SI 3 3) (mult:SI (sign_extend:SI (subreg:HI (reg:SI 128) 2)) (sign_extend:SI (subreg:HI (reg:SI 127) 2)))) ]) i.e. the "canonical" form of the expression actually matches the RTL pattern used/expected by the rs6000 backend.
next prev parent reply other threads:[~2023-03-05 12:00 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-08-12 11:23 [Bug tree-optimization/106594] New: " tnfchris at gcc dot gnu.org 2022-08-12 12:04 ` [Bug tree-optimization/106594] " rguenth at gcc dot gnu.org 2022-08-12 12:44 ` tnfchris at gcc dot gnu.org 2022-08-12 14:01 ` roger at nextmovesoftware dot com 2022-08-12 14:48 ` tnfchris at gcc dot gnu.org 2022-08-12 17:01 ` roger at nextmovesoftware dot com 2022-08-13 11:34 ` [Bug rtl-optimization/106594] " roger at nextmovesoftware dot com 2022-08-14 12:07 ` tnfchris at gcc dot gnu.org 2022-08-17 1:05 ` hp at gcc dot gnu.org 2022-10-19 7:11 ` rguenth at gcc dot gnu.org 2022-10-19 7:52 ` roger at nextmovesoftware dot com 2023-01-17 4:06 ` roger at nextmovesoftware dot com 2023-02-27 10:00 ` tnfchris at gcc dot gnu.org 2023-02-27 10:03 ` ktkachov at gcc dot gnu.org 2023-03-04 22:26 ` segher at gcc dot gnu.org 2023-03-05 8:06 ` roger at nextmovesoftware dot com 2023-03-05 12:00 ` roger at nextmovesoftware dot com [this message] 2023-03-05 15:23 ` segher at gcc dot gnu.org 2023-03-05 19:23 ` tnfchris at gcc dot gnu.org 2023-03-06 7:51 ` rguenth at gcc dot gnu.org 2023-03-06 10:38 ` rsandifo at gcc dot gnu.org 2023-03-06 11:07 ` jakub at gcc dot gnu.org 2023-03-07 11:32 ` roger at nextmovesoftware dot com 2023-03-13 9:30 ` roger at nextmovesoftware dot com 2023-04-17 11:41 ` jakub at gcc dot gnu.org 2023-04-17 12:58 ` jakub at gcc dot gnu.org 2023-04-26 6:56 ` [Bug rtl-optimization/106594] [13/14 " rguenth at gcc dot gnu.org 2023-07-27 9:23 ` rguenth at gcc dot gnu.org 2023-10-30 16:19 ` segher at gcc dot gnu.org 2024-05-21 9:12 ` [Bug rtl-optimization/106594] [13/14/15 " jakub at gcc dot gnu.org
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