From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 34579 invoked by alias); 9 Dec 2016 14:42:01 -0000 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 Received: (qmail 34565 invoked by uid 89); 9 Dec 2016 14:42:00 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-4.9 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: foss.arm.com Received: from foss.arm.com (HELO foss.arm.com) (217.140.101.70) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 09 Dec 2016 14:41:50 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0275CCF6; Fri, 9 Dec 2016 06:41:49 -0800 (PST) Received: from localhost (e105548-lin.manchester.arm.com [10.45.32.67]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7E05A3F24D; Fri, 9 Dec 2016 06:41:48 -0800 (PST) From: Richard Sandiford To: Richard Biener Mail-Followup-To: Richard Biener ,GCC Patches , richard.sandiford@arm.com Cc: GCC Patches Subject: Re: [24/67] Replace a != BLKmode check with is_a References: <87h96dp8u6.fsf@e105548-lin.cambridge.arm.com> <87lgvpl06o.fsf@e105548-lin.cambridge.arm.com> Date: Fri, 09 Dec 2016 14:42:00 -0000 In-Reply-To: (Richard Biener's message of "Fri, 9 Dec 2016 14:22:28 +0100") Message-ID: <8737hxdv11.fsf@e105548-lin.cambridge.arm.com> User-Agent: Gnus/5.130012 (Ma Gnus v0.12) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-SW-Source: 2016-12/txt/msg00860.txt.bz2 Richard Biener writes: > On Fri, Dec 9, 2016 at 2:08 PM, Richard Sandiford > wrote: >> This patch replaces a check against BLKmode with a check >> of is_a , in a case where scalar integer >> modes were the only useful alternatives left. > > So why's BLKmode no longer sth valid to check against? The check is > only there to guard GET_MODE_ALIGNMENT / SLOW_UNALIGNED_ACCESS. Checking against BLKmode is still valid. The patch is just rewriting the check into an alternative form. The end goal is to operate on scalar_int_modes in cases where we know the mode is an integer. In this case the mode we're checking is the result of a type_for_size call, which is defined to always return an integer type: /* Given PRECISION and UNSIGNEDP, return a suitable type-tree for an integer type with at least that precision. */ TBH I was a bit surprised we could see a BLKmode integer type; I thought we disallowed types that didn't have a suitable scalar_mode_supported_p mode. But assuming that the check is necessary, the only thing it lets through are scalar integer modes. Thanks, Richard >> diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c >> index d00625b..c6b5411 100644 >> --- a/gcc/gimple-fold.c >> +++ b/gcc/gimple-fold.c >> @@ -713,31 +713,29 @@ gimple_fold_builtin_memory_op (gimple_stmt_iterator *gsi, >> unsigned ilen = tree_to_uhwi (len); >> if (pow2p_hwi (ilen)) >> { >> + scalar_int_mode mode; >> tree type = lang_hooks.types.type_for_size (ilen * 8, 1); >> if (type >> - && TYPE_MODE (type) != BLKmode >> - && (GET_MODE_SIZE (TYPE_MODE (type)) * BITS_PER_UNIT >> - == ilen * 8) >> + && is_a (TYPE_MODE (type), &mode) >> + && GET_MODE_SIZE (mode) * BITS_PER_UNIT == ilen * 8 >> /* If the destination pointer is not aligned we must be able >> to emit an unaligned store. */ >> - && (dest_align >= GET_MODE_ALIGNMENT (TYPE_MODE (type)) >> - || !SLOW_UNALIGNED_ACCESS (TYPE_MODE (type), dest_align) >> - || (optab_handler (movmisalign_optab, TYPE_MODE (type)) >> + && (dest_align >= GET_MODE_ALIGNMENT (mode) >> + || !SLOW_UNALIGNED_ACCESS (mode, dest_align) >> + || (optab_handler (movmisalign_optab, mode) >> != CODE_FOR_nothing))) >> { >> tree srctype = type; >> tree desttype = type; >> - if (src_align < GET_MODE_ALIGNMENT (TYPE_MODE (type))) >> + if (src_align < GET_MODE_ALIGNMENT (mode)) >> srctype = build_aligned_type (type, src_align); >> tree srcmem = fold_build2 (MEM_REF, srctype, src, off0); >> tree tem = fold_const_aggregate_ref (srcmem); >> if (tem) >> srcmem = tem; >> - else if (src_align < GET_MODE_ALIGNMENT (TYPE_MODE (type)) >> - && SLOW_UNALIGNED_ACCESS (TYPE_MODE (type), >> - src_align) >> - && (optab_handler (movmisalign_optab, >> - TYPE_MODE (type)) >> + else if (src_align < GET_MODE_ALIGNMENT (mode) >> + && SLOW_UNALIGNED_ACCESS (mode, src_align) >> + && (optab_handler (movmisalign_optab, mode) >> == CODE_FOR_nothing)) >> srcmem = NULL_TREE; >> if (srcmem) >> @@ -753,7 +751,7 @@ gimple_fold_builtin_memory_op (gimple_stmt_iterator *gsi, >> gimple_set_vuse (new_stmt, gimple_vuse (stmt)); >> gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT); >> } >> - if (dest_align < GET_MODE_ALIGNMENT (TYPE_MODE (type))) >> + if (dest_align < GET_MODE_ALIGNMENT (mode)) >> desttype = build_aligned_type (type, dest_align); >> new_stmt >> = gimple_build_assign (fold_build2 (MEM_REF, desttype, >>