From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 7877) id 0B7613858C60; Fri, 26 Jan 2024 08:13:10 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 0B7613858C60 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1706256791; bh=IEZt2zbdvk2sbM7ML+klBrZdDSF97KRDFQWIDVNIeak=; h=From:To:Subject:Date:From; b=VUQbAi4e7BDCS57V54+HswuOtzahspRMtf5VOWQH84TJaIFF0uNxPe7Y4rOckiKHH o+wpNPRAChEMsxmbvbhzMJOTFx+Dka2JnqEfFN3lqW6SdZwm9NyTqV3wj6yvJYsJzf lTyqFOSxHa/PUhMHVfK80WgTG48ywVf0kf5UDGc4= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: LuluCheng To: gcc-cvs@gcc.gnu.org Subject: [gcc r14-8444] LoongArch: Optimize implementation of single-precision floating-point approximate division. X-Act-Checkin: gcc X-Git-Author: Li Wei X-Git-Refname: refs/heads/master X-Git-Oldrev: bfd6b36f08021f023e0e9223f5aea315b74a5c56 X-Git-Newrev: 58a27738c57fbf73c367b85537b714c29e0d5825 Message-Id: <20240126081311.0B7613858C60@sourceware.org> Date: Fri, 26 Jan 2024 08:13:10 +0000 (GMT) List-Id: https://gcc.gnu.org/g:58a27738c57fbf73c367b85537b714c29e0d5825 commit r14-8444-g58a27738c57fbf73c367b85537b714c29e0d5825 Author: Li Wei Date: Wed Jan 24 17:44:17 2024 +0800 LoongArch: Optimize implementation of single-precision floating-point approximate division. We found that in the spec17 521.wrf program, some loop invariant code generated from single-precision floating-point approximate division calculation failed to propose a loop. This is because the pseudo-register that stores the intermediate temporary calculation results is rewritten in the implementation of single-precision floating-point approximate division, failing to propose invariants in the loop2_invariant pass. To this end, the intermediate temporary calculation results are stored in new pseudo-registers without destroying the read-write dependency, so that they could be recognized as loop invariants in the loop2_invariant pass. After optimization, the number of instructions of 521.wrf is reduced by 0.18% compared with before optimization (1716612948501 -> 1713471771364). gcc/ChangeLog: * config/loongarch/loongarch.cc (loongarch_emit_swdivsf): Adjust. gcc/testsuite/ChangeLog: * gcc.target/loongarch/invariant-recip.c: New test. Diff: --- gcc/config/loongarch/loongarch.cc | 19 +++++++++---- .../gcc.target/loongarch/invariant-recip.c | 33 ++++++++++++++++++++++ 2 files changed, 46 insertions(+), 6 deletions(-) diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc index dba1252c8f71..b494040d165d 100644 --- a/gcc/config/loongarch/loongarch.cc +++ b/gcc/config/loongarch/loongarch.cc @@ -10847,16 +10847,23 @@ void loongarch_emit_swdivsf (rtx res, rtx a, rtx b, machine_mode mode) /* x0 = 1./b estimate. */ emit_insn (gen_rtx_SET (x0, gen_rtx_UNSPEC (mode, gen_rtvec (1, b), unspec))); - /* 2.0 - b * x0 */ + /* e0 = 2.0 - b * x0. */ emit_insn (gen_rtx_SET (e0, gen_rtx_FMA (mode, gen_rtx_NEG (mode, b), x0, mtwo))); - /* x0 = a * x0 */ if (a != CONST1_RTX (mode)) - emit_insn (gen_rtx_SET (x0, gen_rtx_MULT (mode, a, x0))); - - /* res = e0 * x0 */ - emit_insn (gen_rtx_SET (res, gen_rtx_MULT (mode, e0, x0))); + { + rtx e1 = gen_reg_rtx (mode); + /* e1 = a * x0. */ + emit_insn (gen_rtx_SET (e1, gen_rtx_MULT (mode, a, x0))); + /* res = e0 * e1. */ + emit_insn (gen_rtx_SET (res, gen_rtx_MULT (mode, e0, e1))); + } + else + { + /* res = e0 * x0. */ + emit_insn (gen_rtx_SET (res, gen_rtx_MULT (mode, e0, x0))); + } } static bool diff --git a/gcc/testsuite/gcc.target/loongarch/invariant-recip.c b/gcc/testsuite/gcc.target/loongarch/invariant-recip.c new file mode 100644 index 000000000000..2f64f6ed5e50 --- /dev/null +++ b/gcc/testsuite/gcc.target/loongarch/invariant-recip.c @@ -0,0 +1,33 @@ +/* { dg-do compile } */ +/* { dg-options "-Ofast -march=loongarch64 -mabi=lp64d -mrecip -mfrecipe -fdump-rtl-loop2_invariant " } */ +/* { dg-final { scan-rtl-dump "Decided to move dependent invariant" "loop2_invariant" } } */ + +void +nislfv_rain_plm (int im, int km, float dzl[im][km], float rql[im][km], + float dt) +{ + int i, k; + float con1, decfl; + float dz[km], qn[km], wi[km + 1]; + + for (i = 0; i < im; i++) + { + for (k = 0; k < km; k++) + { + dz[k] = dzl[i][k]; + } + con1 = 0.05; + for (k = km - 1; k >= 0; k--) + { + decfl = (wi[k + 1] - wi[k]) * dt / dz[k]; + if (decfl > con1) + { + wi[k] = wi[k + 1] - con1 * dz[k] / dt; + } + } + for (k = 0; k < km; k++) + { + rql[i][k] = qn[k]; + } + } +}