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From: "mkuvyrkov at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/113542] [14 Regression] gcc.target/arm/bics_3.c regression after change for pr111267 Date: Thu, 25 Jan 2024 09:51:13 +0000 [thread overview] Message-ID: <bug-113542-4-FCGetyagIj@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-113542-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113542 Maxim Kuvyrkov <mkuvyrkov at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |mkuvyrkov at gcc dot gnu.org --- Comment #3 from Maxim Kuvyrkov <mkuvyrkov at gcc dot gnu.org> --- Copy-pasting my comment from https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111267#c15 : I've looked into the reason for the above failures, and it seems to be not an issue. After the patch fwprop1 decides to do an additional propagation, which was considered as "would increase complexity of pattern" before the patch. This results in change from "bics; mov" to "bic; subs". If I understand ARM assembler correctly, handling of sign was shifted from "bics" to "subs" instruction. This is the actual code: BEFORE: bics r0, r0, r1 @ 9 [c=4 l=4] *andsi_notsi_si_compare0_scratch mov r0, #1 @ 23 [c=4 l=4] *thumb2_movsi_vfp/1 it eq moveq r0, #0 @ 26 [c=8 l=4] *p *thumb2_movsi_vfp/2 bx lr @ 29 [c=8 l=4] *thumb2_return and AFTER: bic r0, r0, r1 @ 8 [c=4 l=4] andsi_notsi_si subs r0, r0, #0 @ 22 [c=4 l=4] cmpsi2_addneg/0 it ne movne r0, #1 @ 23 [c=8 l=4] *p *thumb2_movsi_vfp/2 bx lr @ 26 [c=8 l=4] *thumb2_return If I don't hear anything to the contrary, I'll update the testcase to accept both "bic" and "bics".
next prev parent reply other threads:[~2024-01-25 9:51 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-01-22 15:46 [Bug rtl-optimization/113542] New: " roger at nextmovesoftware dot com 2024-01-24 12:48 ` [Bug rtl-optimization/113542] " rearnsha at gcc dot gnu.org 2024-01-24 16:42 ` [Bug target/113542] [14 Regression] " rearnsha at gcc dot gnu.org 2024-01-25 9:51 ` mkuvyrkov at gcc dot gnu.org [this message] 2024-01-31 14:33 ` rguenth at gcc dot gnu.org 2024-02-21 12:47 ` mkuvyrkov at gcc dot gnu.org 2024-03-07 20:47 ` law at gcc dot gnu.org 2024-03-08 17:08 ` cvs-commit at gcc dot gnu.org 2024-03-08 17:15 ` rearnsha at gcc dot gnu.org
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