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From: "law at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/108247] New: Missed opportunity to generate shNadd on risc-v Date: Wed, 28 Dec 2022 19:07:52 +0000 [thread overview] Message-ID: <bug-108247-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108247 Bug ID: 108247 Summary: Missed opportunity to generate shNadd on risc-v Product: gcc Version: 13.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: law at gcc dot gnu.org CC: rzinsly at ventanamicro dot com Target Milestone: --- Target: risc-v int sub2(int a, long long b) { b = (b << 32) >> 31; unsigned int x = a + b; return x; } When compiled with Zba should ideally generate something like this: sh1add a0, a1, a0 sext.w a0, a0 ret I suspect we need to match something like this as a define_split: Failed to match this instruction: (set (reg:SI 142 [ x ]) (plus:SI (subreg:SI (and:DI (ashift:DI (reg:DI 146) (const_int 1 [0x1])) (const_int 4294967294 [0xfffffffe])) 0) (subreg:SI (reg:DI 145) 0))) Or this: (set (reg:DI 144 [ x ]) (sign_extend:DI (plus:SI (subreg:SI (and:DI (ashift:DI (reg:DI 146) (const_int 1 [0x1])) (const_int 4294967294 [0xfffffffe])) 0) (subreg:SI (reg:DI 145) 0))))
next reply other threads:[~2022-12-28 19:07 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-12-28 19:07 law at gcc dot gnu.org [this message] 2022-12-29 1:36 ` [Bug target/108247] " andrew at sifive dot com 2022-12-29 1:42 ` law at gcc dot gnu.org 2023-04-20 14:52 ` law at gcc dot gnu.org
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