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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/104582] [11/12 Regression] Unoptimal code for __negdi2 (and others) from libgcc2 due to unwanted vectorization Date: Fri, 18 Feb 2022 13:45:35 +0000 [thread overview] Message-ID: <bug-104582-4-J2bYeI7iY4@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-104582-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104582 --- Comment #17 from Richard Biener <rguenth at gcc dot gnu.org> --- For FAIL: gcc.target/i386/pr91446.c scan-assembler-times vmovdqa[^\\n\\r]*xmm[0-9] 2 we used to produce 0000000000000000 <foo>: 0: 48 83 ec 28 sub $0x28,%rsp 4: c4 e1 f9 6e d7 vmovq %rdi,%xmm2 9: c4 e1 f9 6e da vmovq %rdx,%xmm3 e: c4 e3 e9 22 ce 01 vpinsrq $0x1,%rsi,%xmm2,%xmm1 14: c4 e3 e1 22 c1 01 vpinsrq $0x1,%rcx,%xmm3,%xmm0 1a: 48 89 e7 mov %rsp,%rdi 1d: c5 f9 7f 0c 24 vmovdqa %xmm1,(%rsp) 22: c5 f9 7f 44 24 10 vmovdqa %xmm0,0x10(%rsp) 28: e8 00 00 00 00 call 2d <foo+0x2d> 2d: 48 83 c4 28 add $0x28,%rsp 31: c3 ret but now reject this on costing grounds. The scalar code is 0000000000000000 <foo>: 0: 48 83 ec 28 sub $0x28,%rsp 4: 48 89 3c 24 mov %rdi,(%rsp) 8: 48 89 e7 mov %rsp,%rdi b: 48 89 74 24 08 mov %rsi,0x8(%rsp) 10: 48 89 54 24 10 mov %rdx,0x10(%rsp) 15: 48 89 4c 24 18 mov %rcx,0x18(%rsp) 1a: e8 00 00 00 00 call 1f <foo+0x1f> 1f: 48 83 c4 28 add $0x28,%rsp 23: c3 ret I think the scalar variant is 5 uops up to the call while the vector variant is 9 uops. The scalar variant can also execute 4 of the uops in parallel (well, I guess only up to 3 with 3 store ports). I think the scalar variant is better and so I'm inclined to adjust the testcase.
next prev parent reply other threads:[~2022-02-18 13:45 UTC|newest] Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-02-17 12:30 [Bug target/104582] New: Unoptimal code for __negdi2 (and others) from libgcc2 ubizjak at gmail dot com 2022-02-17 12:35 ` [Bug tree-optimization/104582] " ubizjak at gmail dot com 2022-02-17 12:45 ` ubizjak at gmail dot com 2022-02-17 15:28 ` [Bug tree-optimization/104582] [11/12 Regression] Unoptimal code for __negdi2 (and others) from libgcc2 due to unwanted vectorization jakub at gcc dot gnu.org 2022-02-17 16:35 ` jakub at gcc dot gnu.org 2022-02-17 16:40 ` jakub at gcc dot gnu.org 2022-02-18 0:43 ` pinskia at gcc dot gnu.org 2022-02-18 7:26 ` rguenth at gcc dot gnu.org 2022-02-18 8:37 ` jakub at gcc dot gnu.org 2022-02-18 8:48 ` rguenth at gcc dot gnu.org 2022-02-18 8:53 ` rguenth at gcc dot gnu.org 2022-02-18 9:02 ` jakub at gcc dot gnu.org 2022-02-18 9:28 ` rguenther at suse dot de 2022-02-18 10:19 ` rguenth at gcc dot gnu.org 2022-02-18 10:22 ` rguenth at gcc dot gnu.org 2022-02-18 10:50 ` rguenth at gcc dot gnu.org 2022-02-18 11:31 ` rguenth at gcc dot gnu.org 2022-02-18 13:37 ` rguenth at gcc dot gnu.org 2022-02-18 13:45 ` rguenth at gcc dot gnu.org [this message] 2022-02-18 21:16 ` pinskia at gcc dot gnu.org 2022-02-22 7:58 ` cvs-commit at gcc dot gnu.org 2022-02-22 7:59 ` cvs-commit at gcc dot gnu.org 2022-02-22 7:59 ` cvs-commit at gcc dot gnu.org 2022-02-22 7:59 ` [Bug tree-optimization/104582] [11 " rguenth at gcc dot gnu.org 2022-04-07 8:15 ` rguenth at gcc dot gnu.org 2022-04-21 7:51 ` rguenth at gcc dot gnu.org 2023-05-29 10:06 ` jakub at gcc dot gnu.org
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