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From: "acsawdey at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/103197] New: ppc inline expansion of memcpy/memmove should not use lxsibzx/stxsibx for a single byte Date: Thu, 11 Nov 2021 18:27:48 +0000 [thread overview] Message-ID: <bug-103197-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103197 Bug ID: 103197 Summary: ppc inline expansion of memcpy/memmove should not use lxsibzx/stxsibx for a single byte Product: gcc Version: 10.3.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: acsawdey at gcc dot gnu.org Target Milestone: --- This got broken sometime in gcc 10 timeframe. For this test case: #include <string.h> void m(char *a, char *b) { memcpy(a,b,9); } AT13 (gcc 9.3.1) produces: m: .LFB0: .cfi_startproc ld 10,0(4) lbz 9,8(4) std 10,0(3) stb 9,8(3) blr .long 0 .byte 0,0,0,0,0,0,0,0 .cfi_endproc which is the expected code to copy 9 bytes. AT14 (gcc 10.3.1), gcc 11, and current trunk all produce: m: .LFB0: .cfi_startproc addi 10,4,8 ld 9,0(4) lxsibzx 0,0,10 std 9,0(3) addi 9,3,8 stxsibx 0,0,9 blr .long 0 .byte 0,0,0,0,0,0,0,0 .cfi_endproc which is really bad, mixing gpr and vsx. The inline expansion code in expand_block_move() does not attempt to generate vsx code at all unless the size is at least 16 bytes.
next reply other threads:[~2021-11-11 18:27 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-11 18:27 acsawdey at gcc dot gnu.org [this message] 2021-11-11 18:46 ` [Bug target/103197] " acsawdey at gcc dot gnu.org 2021-11-11 19:36 ` acsawdey at gcc dot gnu.org 2021-11-12 11:19 ` segher at gcc dot gnu.org 2021-11-15 16:02 ` acsawdey at gcc dot gnu.org 2021-11-16 16:40 ` acsawdey at gcc dot gnu.org 2021-11-17 21:40 ` segher at gcc dot gnu.org 2021-11-18 1:31 ` amodra at gmail dot com 2021-11-18 18:11 ` segher at gcc dot gnu.org 2022-01-05 18:15 ` segher at gcc dot gnu.org 2022-01-05 18:18 ` segher at gcc dot gnu.org 2022-01-17 5:51 ` guihaoc at gcc dot gnu.org 2022-02-04 1:51 ` segher at gcc dot gnu.org 2022-04-21 21:31 ` cvs-commit at gcc dot gnu.org 2022-04-21 21:31 ` cvs-commit at gcc dot gnu.org 2022-08-16 21:24 ` [Bug target/103197] [10/11] " cvs-commit at gcc dot gnu.org 2022-08-16 21:24 ` cvs-commit at gcc dot gnu.org 2022-08-16 23:35 ` cvs-commit at gcc dot gnu.org 2022-08-16 23:38 ` segher at gcc dot gnu.org
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