From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16775 invoked by alias); 14 Jul 2011 14:38:51 -0000 Received: (qmail 16767 invoked by uid 22791); 14 Jul 2011 14:38:50 -0000 X-SWARE-Spam-Status: No, hits=-1.1 required=5.0 tests=AWL,BAYES_00,MISSING_HEADERS,RP_MATCHES_RCVD,TW_TM X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (38.113.113.100) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 14 Jul 2011 14:38:36 +0000 Received: (qmail 11498 invoked from network); 14 Jul 2011 14:38:35 -0000 Received: from unknown (HELO ?192.168.0.100?) (ams@127.0.0.2) by mail.codesourcery.com with ESMTPA; 14 Jul 2011 14:38:35 -0000 Message-ID: <4E1EFF68.10201@codesourcery.com> Date: Thu, 14 Jul 2011 14:44:00 -0000 From: Andrew Stubbs User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:5.0) Gecko/20110627 Thunderbird/5.0 MIME-Version: 1.0 CC: gcc-patches@gcc.gnu.org, patches@linaro.org Subject: Re: [PATCH (7/7)] Mixed-sign multiplies using narrowest mode References: <4E034EF2.3070503@codesourcery.com> <4E03511F.9040507@codesourcery.com> <4E09FFEF.6010603@codesourcery.com> In-Reply-To: <4E09FFEF.6010603@codesourcery.com> Content-Type: multipart/mixed; boundary="------------090806070901010906020109" Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2011-07/txt/msg01162.txt.bz2 This is a multi-part message in MIME format. --------------090806070901010906020109 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-length: 1085 On 28/06/11 17:23, Andrew Stubbs wrote: > On 23/06/11 15:43, Andrew Stubbs wrote: >> Patch 4 introduced support for using signed multiplies to code unsigned >> multiplies in a narrower mode. Patch 5 then introduced support for >> mis-matched input modes. >> >> These two combined mean that there is case where only the smaller of two >> inputs is unsigned, and yet it still tries to user a mode wider than the >> larger, signed input. This is bad because it means unnecessary extends >> and because the wider operation might not exist. >> >> This patch catches that case, and ensures that the smaller, unsigned >> input, is zero-extended to match the mode of the larger, signed input. >> >> Of course, both inputs may still have to be extended to fit the nearest >> available instruction, so it doesn't make a difference every time. >> >> OK? > > This update fixes Janis' issue with the testsuite. And this version is updated to fit the changes made earlier in the series, and also to use the precision, instead of the mode-size, in order to better optimize bitfields. OK? Andrew --------------090806070901010906020109 Content-Type: text/x-patch; name="widening-multiplies-7.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="widening-multiplies-7.patch" Content-length: 3017 2011-06-24 Andrew Stubbs gcc/ * tree-ssa-math-opts.c (convert_mult_to_widen): Better handle unsigned inputs of different modes. (convert_plusminus_to_widen): Likewise. gcc/testsuite/ * gcc.target/arm/wmul-9.c: New file. * gcc.target/arm/wmul-bitfield-2.c: New file. --- /dev/null +++ b/gcc/testsuite/gcc.target/arm/wmul-9.c @@ -0,0 +1,10 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -march=armv7-a" } */ + +long long +foo (long long a, short *b, char *c) +{ + return a + *b * *c; +} + +/* { dg-final { scan-assembler "smlalbb" } } */ --- /dev/null +++ b/gcc/testsuite/gcc.target/arm/wmul-bitfield-2.c @@ -0,0 +1,17 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -march=armv7-a" } */ + +struct bf +{ + int a : 3; + unsigned int b : 15; + int c : 3; +}; + +long long +foo (long long a, struct bf b, struct bf c) +{ + return a + b.b * c.c; +} + +/* { dg-final { scan-assembler "smlalbb" } } */ --- a/gcc/tree-ssa-math-opts.c +++ b/gcc/tree-ssa-math-opts.c @@ -2121,9 +2121,18 @@ convert_mult_to_widen (gimple stmt, gimple_stmt_iterator *gsi) { if (op != smul_widen_optab) { - from_mode = GET_MODE_WIDER_MODE (from_mode); - if (GET_MODE_SIZE (to_mode) <= GET_MODE_SIZE (from_mode)) - return false; + /* We can use a signed multiply with unsigned types as long as + there is a wider mode to use, or it is the smaller of the two + types that is unsigned. Note that type1 >= type2, always. */ + if ((TYPE_UNSIGNED (type1) + && TYPE_PRECISION (type1) == GET_MODE_PRECISION (from_mode)) + || (TYPE_UNSIGNED (type2) + && TYPE_PRECISION (type2) == GET_MODE_PRECISION (from_mode))) + { + from_mode = GET_MODE_WIDER_MODE (from_mode); + if (GET_MODE_SIZE (to_mode) <= GET_MODE_SIZE (from_mode)) + return false; + } op = smul_widen_optab; handler = find_widening_optab_handler_and_mode (op, to_mode, @@ -2290,14 +2299,20 @@ convert_plusminus_to_widen (gimple_stmt_iterator *gsi, gimple stmt, /* There's no such thing as a mixed sign madd yet, so use a wider mode. */ if (from_unsigned1 != from_unsigned2) { - enum machine_mode mode = GET_MODE_WIDER_MODE (from_mode); - if (GET_MODE_PRECISION (mode) < GET_MODE_PRECISION (to_mode)) + /* We can use a signed multiply with unsigned types as long as + there is a wider mode to use, or it is the smaller of the two + types that is unsigned. Note that type1 >= type2, always. */ + if ((from_unsigned1 + && TYPE_PRECISION (type1) == GET_MODE_PRECISION (from_mode)) + || (from_unsigned2 + && TYPE_PRECISION (type2) == GET_MODE_PRECISION (from_mode))) { - from_mode = mode; - from_unsigned1 = from_unsigned2 = false; + from_mode = GET_MODE_WIDER_MODE (from_mode); + if (GET_MODE_SIZE (from_mode) >= GET_MODE_SIZE (to_mode)) + return false; } - else - return false; + + from_unsigned1 = from_unsigned2 = false; } /* If there was a conversion between the multiply and addition --------------090806070901010906020109--