From patchwork Wed Aug 12 01:11:36 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 506294 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 1222F1401CD for ; Wed, 12 Aug 2015 11:13:23 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=gcc.gnu.org header.i=@gcc.gnu.org header.b=M2pZYA3+; dkim-atps=neutral DomainKey-Signature: a=rsa-sha1; c=nofws; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:from :to:cc:subject:date:message-id:in-reply-to:references; q=dns; s= default; b=ki3OJr/8YMZkvRHVG3lHgJTpyNt9NEImOxkKx4GiFeYITN5QCByh9 7RqCPlnBtuzPMOgGF/M4HnGcs1ma7Sp09/ueEHiffvArVk83Ig69E92EMoq6l9ti acnxfJEZ8shZuh9i6eunp+J5n0cse1E2Agwrhk11gIN9bKyi3qsiys= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:from :to:cc:subject:date:message-id:in-reply-to:references; s= default; bh=KbNpnIrex1It+U21t8D9ZhHBj3k=; b=M2pZYA3+gnYTraD5Luoc 8VjbRM1c6XJk+5vhGfW/+DeFv5hlDqyHfptY1318AyHVoKf/qLtzG7wXAfELSwhc 5Pk8RSVrLfbkA68aLgNftF/twn4IjqHfqruvltb+w5iKkY+C+RKuZD3Gia7nNNoD AzIuvj/4j/6VNCYpr0esT8g= Received: (qmail 76445 invoked by alias); 12 Aug 2015 01:11:57 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Delivered-To: mailing list gcc-patches@gcc.gnu.org Received: (qmail 76420 invoked by uid 89); 12 Aug 2015 01:11:57 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.2 required=5.0 tests=AWL, BAYES_00, FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM, RCVD_IN_DNSWL_LOW, SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-pa0-f48.google.com Received: from mail-pa0-f48.google.com (HELO mail-pa0-f48.google.com) (209.85.220.48) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Wed, 12 Aug 2015 01:11:55 +0000 Received: by pacrr5 with SMTP id rr5so2212762pac.3 for ; Tue, 11 Aug 2015 18:11:53 -0700 (PDT) X-Received: by 10.66.222.68 with SMTP id qk4mr61088880pac.96.1439341913567; Tue, 11 Aug 2015 18:11:53 -0700 (PDT) Received: from bigtime.twiddle.net (50-194-63-110-static.hfc.comcastbusiness.net. [50.194.63.110]) by smtp.gmail.com with ESMTPSA id kv10sm4167810pbc.2.2015.08.11.18.11.52 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 11 Aug 2015 18:11:52 -0700 (PDT) From: Richard Henderson To: gcc-patches@gcc.gnu.org Cc: David Edelsohn Subject: [PATCH 07/15] rs6000: Generalize left shift in constant generation Date: Tue, 11 Aug 2015 18:11:36 -0700 Message-Id: <1439341904-9345-8-git-send-email-rth@redhat.com> In-Reply-To: <1439341904-9345-1-git-send-email-rth@redhat.com> References: <1439341904-9345-1-git-send-email-rth@redhat.com> X-IsSubscribed: yes Rather than always shift by 32, shift by the total number of zeros required. The improvement to also look to shift out ones comes from Kenner via alpha. Cc: David Edelsohn --- * config/rs6000/rs6000.c (genimm_ppc::exam_search): Use ctz to compute the shift. Also attempt to shift out ones. --- gcc/config/rs6000/rs6000.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 59c5014..b27e476 100644 --- a/gcc/config/rs6000/rs6000.c +++ b/gcc/config/rs6000/rs6000.c @@ -8145,6 +8145,7 @@ genimm_ppc::exam_search (HOST_WIDE_INT c, int budget) { const int sub_budget = budget - 1; HOST_WIDE_INT test; + int bits; /* Simple arithmetic on the low 32-bits. */ test = c & 0xffff; @@ -8181,11 +8182,23 @@ genimm_ppc::exam_search (HOST_WIDE_INT c, int budget) } /* Shift the constant left. */ - test = HOST_WIDE_INT_UC (0xffffffff00000000); - if ((c & test) == c && exam_sub (c >> 32, sub_budget)) + bits = ctz_hwi (c); + if (bits > 0) { - opN (ASHIFT, 32); /* SLDI */ - return true; + /* First try with zeros being shifted out. */ + HOST_WIDE_INT sub_c = (unsigned HOST_WIDE_INT)c >> bits; + bool ok = exam_sub (sub_c, sub_budget); + if (!ok) + { + /* If that failed, try with ones being shifted out. */ + sub_c |= ~(HOST_WIDE_INT_M1U >> bits); + ok = exam_sub (sub_c, sub_budget); + } + if (ok) + { + opN (ASHIFT, bits); /* SLDI */ + return true; + } } return false;