From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 108067 invoked by alias); 29 Oct 2015 15:23:18 -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 108051 invoked by uid 89); 29 Oct 2015 15:23:17 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-yk0-f171.google.com Received: from mail-yk0-f171.google.com (HELO mail-yk0-f171.google.com) (209.85.160.171) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Thu, 29 Oct 2015 15:23:16 +0000 Received: by ykek133 with SMTP id k133so46064915yke.2 for ; Thu, 29 Oct 2015 08:23:14 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.13.202.141 with SMTP id m135mr1781099ywd.305.1446132194086; Thu, 29 Oct 2015 08:23:14 -0700 (PDT) Received: by 10.37.117.136 with HTTP; Thu, 29 Oct 2015 08:23:13 -0700 (PDT) In-Reply-To: <20151029150215.GA34652@kam.mff.cuni.cz> References: <20151014162944.GE16672@kam.mff.cuni.cz> <1456448.Tt4DpGVrAE@polaris> <20151021215701.GA14675@atrey.karlin.mff.cuni.cz> <2210014.Qgk3pAbeYD@polaris> <20151029033922.GA52478@kam.mff.cuni.cz> <20151029150215.GA34652@kam.mff.cuni.cz> Date: Thu, 29 Oct 2015 15:24:00 -0000 Message-ID: Subject: Re: Add VIEW_CONVERT_EXPR to operand_equal_p From: Richard Biener To: Jan Hubicka Cc: Eric Botcazou , GCC Patches Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2015-10/txt/msg03198.txt.bz2 On Thu, Oct 29, 2015 at 4:02 PM, Jan Hubicka wrote: >> >> IMHO it was always wrong/fragile for backends to look at the actual arguments to >> decide on the calling convention. The backends should _solely_ rely on >> gimple_call_fntype and its TYPE_ARG_TYPES here. >> >> Of course then there are varargs ... (not sure if we hit this here). > > Yep, you have varargs and K&R prototypes, so it can't work this way. Well, then I suppose we need to compute the ABI upfront when we gimplify from the orginal args (like we preserve fntype). Having a separate fntype was really meant to make us preserve the ABI throughout the GIMPLE phase... >> >> But yes, the VIEW_CONVERT "stripping" is a bit fragile and I don't remember >> what exactly we gain from it (when not done on registers). > > I guess gain is really limited to Ada - there are very few cases we do VCE otherwise. > (I think we could do more of them). We can make useless_type_conversion NOP/CONVERT > only. That in fact makes quite a sense because those are types with gimple operations > on it. Perhaps also VCE on vectors, but not VCE in general. > > Honza >> >> But I also don't see where we do the stripping mentioned on memory references. >> The match.pd pattern doesn't apply to memory, only in the GENERIC path >> which is guarded with exact type equality. So I can't see where we end up >> stripping the V_C_E. >> >> There is one bogus case still in fold-const.c: >> >> case VIEW_CONVERT_EXPR: >> if (TREE_CODE (op0) == MEM_REF) >> /* ??? Bogus for aligned types. */ >> return fold_build2_loc (loc, MEM_REF, type, >> TREE_OPERAND (op0, 0), TREE_OPERAND (op0, 1)); >> >> return NULL_TREE; >> >> that comment is only in my local tree ... (we lose alignment info that is >> on the original MEM_REF type which may be a smaller one). >> >> Richard. >> >> > Honza >> >> >> >> >> >> * gnat.dg/discr44.adb: New test. >> >> >> >> -- >> >> Eric Botcazou >> > >> >> -- { dg-do run } >> >> -- { dg-options "-gnatws" } >> >> >> >> procedure Discr44 is >> >> >> >> function Ident (I : Integer) return Integer is >> >> begin >> >> return I; >> >> end; >> >> >> >> type Int is range 1 .. 10; >> >> >> >> type Str is array (Int range <>) of Character; >> >> >> >> type Parent (D1, D2 : Int; B : Boolean) is record >> >> S : Str (D1 .. D2); >> >> end record; >> >> >> >> type Derived (D : Int) is new Parent (D1 => D, D2 => D, B => False); >> >> >> >> X1 : Derived (D => Int (Ident (7))); >> >> >> >> begin >> >> if X1.D /= 7 then >> >> raise Program_Error; >> >> end if; >> >> end; >> >