public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "juzhe.zhong at rivai dot ai" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/110751] RISC-V: Suport undefined value that allows VSETVL PASS use TA/MA Date: Tue, 12 Sep 2023 11:44:57 +0000 [thread overview] Message-ID: <bug-110751-4-jT8LLPnDo9@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-110751-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110751 --- Comment #23 from JuzheZhong <juzhe.zhong at rivai dot ai> --- Hi, Richard and Richi. I found a way to simulate "undefine" in COND_LEN_xxx pattern for the ELSE value that doesn't matter. First, return size type 0 in else_value target hook: /* Use size_type 0 which is represented as const0_rtx in RTL to simulate undefine else value since GCC doesn't undefine value in TREE/GIMPLE representation. TODO: We may will need to support undefine value in TREE/GIMPLE middle-end IR. But current approach is good enough for RVV codegen/performance. */ static tree riscv_preferred_else_value (unsigned ifn, tree vectype, unsigned int nops, tree *ops) { if (riscv_v_ext_mode_p (TYPE_MODE (vectype))) return build_zero_cst (size_type_node); return default_preferred_else_value (ifn, vectype, nops, ops); } Note that we can't return VECTOR_CST with all 0. Since a VECTROR_CST with all 0 may matter and the real value we need. So, to simulate "undefine", I pass a '0' which will be represented as const0_rtx in RTX. So the IR will be: vect__7.12_8 = .COND_LEN_DIV ({ -1, ... }, vect__4.8_22, vect__6.11_9, 0 (undefine ELSE value), _37, 0); Then I relax the predicate in COND_LEN_xxx pattern. It works and pass all the tests. Consider this following case: void foo (int32_t *__restrict a, int32_t *__restrict b, int n) { for (int i = 0; i < n; i++) a[i] = a[i] / b[i]; } Before: foo: ble a2,zero,.L5 mv a4,a0 vsetvli a5,zero,e32,m8,ta,ma vmv.v.i v4,0 .L3: vsetvli a5,a2,e32,m8,tu,ma vmv8r.v v1,v4 slli a3,a5,2 vle32.v v3,0(a0) vle32.v v2,0(a1) sub a2,a2,a5 vdiv.vv v1,v3,v2 vse32.v v1,0(a4) add a0,a0,a3 add a1,a1,a3 add a4,a4,a3 bne a2,zero,.L3 .L5: ret After: foo: ble a2,zero,.L5 mv a4,a0 .L3: vsetvli a5,a2,e32,m8,ta,ma slli a3,a5,2 vle32.v v8,0(a0) vle32.v v16,0(a1) sub a2,a2,a5 vdiv.vv v8,v8,v16 vse32.v v8,0(a4) add a0,a0,a3 add a1,a1,a3 add a4,a4,a3 bne a2,zero,.L3 .L5: ret Not so elegant. But it does fix the performance/codegen issue in RVV.
next prev parent reply other threads:[~2023-09-12 11:44 UTC|newest] Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-07-20 9:03 [Bug target/110751] New: " xuli1 at eswincomputing dot com 2023-07-20 9:10 ` [Bug target/110751] " juzhe.zhong at rivai dot ai 2023-07-20 9:30 ` rguenth at gcc dot gnu.org 2023-07-20 9:37 ` rguenth at gcc dot gnu.org 2023-07-20 9:58 ` kito at gcc dot gnu.org 2023-07-20 11:28 ` rguenther at suse dot de 2023-07-20 11:43 ` juzhe.zhong at rivai dot ai 2023-07-20 12:00 ` juzhe.zhong at rivai dot ai 2023-07-20 12:35 ` rguenther at suse dot de 2023-07-20 12:42 ` juzhe.zhong at rivai dot ai 2023-07-20 12:45 ` rguenther at suse dot de 2023-07-20 12:50 ` juzhe.zhong at rivai dot ai 2023-07-20 12:56 ` rguenther at suse dot de 2023-07-20 13:29 ` rsandifo at gcc dot gnu.org 2023-07-20 13:32 ` rguenther at suse dot de 2023-07-20 22:03 ` juzhe.zhong at rivai dot ai 2023-07-21 1:53 ` xuli1 at eswincomputing dot com 2023-07-21 6:17 ` rguenth at gcc dot gnu.org 2023-07-21 12:47 ` rsandifo at gcc dot gnu.org 2023-07-21 12:53 ` rguenth at gcc dot gnu.org 2023-07-21 13:23 ` rsandifo at gcc dot gnu.org 2023-07-24 6:20 ` rguenther at suse dot de 2023-07-25 7:05 ` juzhe.zhong at rivai dot ai 2023-09-12 11:44 ` juzhe.zhong at rivai dot ai [this message] 2023-09-12 14:24 ` rsandifo at gcc dot gnu.org 2023-09-12 14:53 ` juzhe.zhong at rivai dot ai 2023-09-12 15:59 ` rsandifo at gcc dot gnu.org 2023-09-12 16:21 ` juzhe.zhong at rivai dot ai 2023-09-12 16:27 ` juzhe.zhong at rivai dot ai 2023-09-12 16:31 ` juzhe.zhong at rivai dot ai 2023-09-12 22:44 ` juzhe.zhong at rivai dot ai 2023-09-13 7:56 ` rguenth at gcc dot gnu.org 2023-09-13 8:34 ` juzhe.zhong at rivai dot ai 2023-09-13 8:39 ` juzhe.zhong at rivai dot ai 2023-09-13 9:38 ` rguenth at gcc dot gnu.org 2023-09-13 9:39 ` rguenth at gcc dot gnu.org 2023-09-13 9:48 ` juzhe.zhong at rivai dot ai 2023-09-13 9:48 ` juzhe.zhong at rivai dot ai 2023-09-13 10:15 ` rguenther at suse dot de 2023-09-13 22:39 ` rsandifo at gcc dot gnu.org 2023-09-14 8:53 ` juzhe.zhong at rivai dot ai 2023-09-14 9:15 ` richard.sandiford at arm dot com 2023-09-20 16:27 ` cvs-commit at gcc dot gnu.org 2023-09-21 9:13 ` cvs-commit at gcc dot gnu.org 2023-09-21 9:28 ` juzhe.zhong at rivai dot ai 2023-09-22 7:31 ` xuli1 at eswincomputing dot com 2023-09-22 7:33 ` xuli1 at eswincomputing dot com
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bug-110751-4-jT8LLPnDo9@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).