public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/105546] [11/12/13 Regression] ifconversion introduces many compares with loads Date: Wed, 19 Oct 2022 10:06:12 +0000 [thread overview] Message-ID: <bug-105546-4-RU8gBBIGJU@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-105546-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105546 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Priority|P3 |P2 --- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> --- And it's sinking (of common stores) that turns <bb 2> [local count: 1073741824]: g_344.0_1 = g_344; if (g_344.0_1 != 0) goto <bb 3>; [50.00%] else goto <bb 4>; [50.00%] <bb 3> [local count: 536870913]: <retval>.f0 = 2738; <retval>.f1 = 27943; <retval>.f2 = -1; <retval>.f3 = 171; <retval>.f4 = 3; <retval>.f5 = 4499926296329723445; goto <bb 5>; [100.00%] <bb 4> [local count: 536870913]: <retval>.f0 = 65526; <retval>.f1 = 1; <retval>.f2 = -8; <retval>.f3 = 161; <retval>.f4 = 3409572933270154779; <retval>.f5 = -6; <bb 5> [local count: 1073741824]: return <retval>; into <bb 2> [local count: 1073741824]: g_344.0_1 = g_344; if (g_344.0_1 != 0) goto <bb 4>; [50.00%] else goto <bb 3>; [50.00%] <bb 3> [local count: 536870913]: <bb 4> [local count: 1073741824]: # _16 = PHI <4499926296329723445(2), -6(3)> # _18 = PHI <3(2), 3409572933270154779(3)> # _20 = PHI <171(2), 161(3)> # _22 = PHI <-1(2), -8(3)> # _24 = PHI <27943(2), 1(3)> # _26 = PHI <2738(2), 65526(3)> <retval>.f0 = _26; <retval>.f1 = _24; <retval>.f2 = _22; <retval>.f3 = _20; <retval>.f4 = _18; <retval>.f5 = _16; return <retval>; without that (-fno-tree-sink) we'd get func_1: .LFB0: .cfi_startproc movq %rdi, %rax cmpw $0, g_344(%rip) je .L2 movw $2738, (%rdi) movw $27943, 2(%rdi) movw $-1, 4(%rdi) movb $-85, 6(%rdi) movq $3, 8(%rdi) movabsq $4499926296329723445, %rdx movq %rdx, 16(%rdi) ret .L2: movw $-10, (%rdi) movw $1, 2(%rdi) movw $-8, 4(%rdi) movb $-95, 6(%rdi) movabsq $3409572933270154779, %rcx movq %rcx, 8(%rdi) movq $-6, 16(%rdi) ret or at -O2 now with vectorizing func_1: .LFB0: .cfi_startproc cmpw $0, g_344(%rip) movq %rdi, %rax je .L2 movdqa .LC1(%rip), %xmm0 movl $-1, %ecx movl $1831275186, (%rdi) movw %cx, 4(%rdi) movb $-85, 6(%rdi) movups %xmm0, 8(%rdi) ret .p2align 4,,10 .p2align 3 .L2: movdqa .LC3(%rip), %xmm0 movl $-8, %edx movl $131062, (%rdi) movw %dx, 4(%rdi) movb $-95, 6(%rdi) movups %xmm0, 8(%rdi) ret we could probably improve things by storing into the padding but GIMPLE doesn't know it is allowed to do that. sinking notes /* Insert a PHI to merge differing stored values if necessary. Note that in general inserting PHIs isn't a very good idea as it makes the job of coalescing and register allocation harder. Even common SSA uses on the rhs/lhs might extend their lifetime across multiple edges by this code motion which makes register allocation harder. */ but we don't limit ourselves in the number of PHI nodes to create. Of course since we have two sinking passes now we'd get inconsistent results here, also since vectorization sits inbetween the two.
next prev parent reply other threads:[~2022-10-19 10:06 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-05-10 11:34 [Bug rtl-optimization/105546] New: load introduction when copying a struct absoler at smail dot nju.edu.cn 2022-05-10 11:44 ` [Bug rtl-optimization/105546] load introduction when initializing " absoler at smail dot nju.edu.cn 2022-05-10 21:02 ` [Bug target/105546] [11/12/13 Regression] ifconversion introduces many compares with loads pinskia at gcc dot gnu.org 2022-05-11 7:20 ` rguenth at gcc dot gnu.org 2022-10-19 10:06 ` rguenth at gcc dot gnu.org [this message] 2022-10-19 10:07 ` rguenth at gcc dot gnu.org 2023-01-13 21:30 ` roger at nextmovesoftware dot com 2023-05-29 10:07 ` [Bug target/105546] [11/12/13/14 " jakub at gcc dot gnu.org
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-105546-4-RU8gBBIGJU@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).