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From: "slash.tmp at free dot fr" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/105617] [12/13/14 Regression] Slp is maybe too aggressive in some/many cases Date: Thu, 01 Jun 2023 07:58:52 +0000 [thread overview] Message-ID: <bug-105617-4-C8oiCUKFJT@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-105617-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105617 --- Comment #18 from Mason <slash.tmp at free dot fr> --- Hello Michael_S, As far as I can see, massaging the source helps GCC generate optimal code (in terms of instruction count, not convinced about scheduling). #include <x86intrin.h> typedef unsigned long long u64; void add4i(u64 dst[4], const u64 A[4], const u64 B[4]) { unsigned char c = 0; c = _addcarry_u64(c, A[0], B[0], dst+0); c = _addcarry_u64(c, A[1], B[1], dst+1); c = _addcarry_u64(c, A[2], B[2], dst+2); c = _addcarry_u64(c, A[3], B[3], dst+3); } On godbolt, gcc-{11.4, 12.3, 13.1, trunk} -O3 -march=znver1 all generate the expected: add4i: movq (%rdx), %rax addq (%rsi), %rax movq %rax, (%rdi) movq 8(%rsi), %rax adcq 8(%rdx), %rax movq %rax, 8(%rdi) movq 16(%rsi), %rax adcq 16(%rdx), %rax movq %rax, 16(%rdi) movq 24(%rdx), %rax adcq 24(%rsi), %rax movq %rax, 24(%rdi) ret I'll run a few benchmarks to test optimal scheduling.
next prev parent reply other threads:[~2023-06-01 7:58 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-05-16 12:08 [Bug target/105617] New: Regression in code generation for _addcarry_u64() already5chosen at yahoo dot com 2022-05-16 12:13 ` [Bug target/105617] [12/13 regressi] Slp is maybe too aggressive in some/many cases pinskia at gcc dot gnu.org 2022-05-16 12:14 ` pinskia at gcc dot gnu.org 2022-05-16 12:15 ` rguenth at gcc dot gnu.org 2022-05-16 12:38 ` [Bug target/105617] [12/13 Regression] " already5chosen at yahoo dot com 2022-05-16 13:02 ` already5chosen at yahoo dot com 2022-05-16 14:08 ` already5chosen at yahoo dot com 2022-05-17 2:47 ` crazylht at gmail dot com 2022-05-17 3:29 ` crazylht at gmail dot com 2022-05-17 3:37 ` crazylht at gmail dot com 2022-05-17 6:48 ` rguenth at gcc dot gnu.org 2022-05-17 9:17 ` already5chosen at yahoo dot com 2022-05-17 9:25 ` already5chosen at yahoo dot com 2022-05-19 8:05 ` crazylht at gmail dot com 2022-07-26 11:22 ` rguenth at gcc dot gnu.org 2022-07-26 11:22 ` rguenth at gcc dot gnu.org 2022-07-29 13:21 ` already5chosen at yahoo dot com 2023-05-08 12:24 ` [Bug target/105617] [12/13/14 " rguenth at gcc dot gnu.org 2023-06-01 7:58 ` slash.tmp at free dot fr [this message] 2023-06-07 23:16 ` already5chosen at yahoo dot com 2023-06-13 14:54 ` slash.tmp at free dot fr 2023-06-16 14:56 ` already5chosen at yahoo dot com
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