From patchwork Thu May 12 14:36:31 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jakub Jelinek X-Patchwork-Id: 95321 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]) by ozlabs.org (Postfix) with SMTP id E9F321007D8 for ; Fri, 13 May 2011 00:36:56 +1000 (EST) Received: (qmail 11728 invoked by alias); 12 May 2011 14:36:52 -0000 Received: (qmail 11536 invoked by uid 22791); 12 May 2011 14:36:51 -0000 X-SWARE-Spam-Status: No, hits=-6.5 required=5.0 tests=AWL, BAYES_00, RCVD_IN_DNSWL_HI, SPF_HELO_PASS, T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 12 May 2011 14:36:33 +0000 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p4CEaXGV000999 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 12 May 2011 10:36:33 -0400 Received: from tyan-ft48-01.lab.bos.redhat.com (tyan-ft48-01.lab.bos.redhat.com [10.16.42.4]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p4CEaW7Y024618 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 12 May 2011 10:36:33 -0400 Received: from tyan-ft48-01.lab.bos.redhat.com (localhost.localdomain [127.0.0.1]) by tyan-ft48-01.lab.bos.redhat.com (8.14.4/8.14.4) with ESMTP id p4CEaWmS023720 for ; Thu, 12 May 2011 16:36:32 +0200 Received: (from jakub@localhost) by tyan-ft48-01.lab.bos.redhat.com (8.14.4/8.14.4/Submit) id p4CEaWDk023718 for gcc-patches@gcc.gnu.org; Thu, 12 May 2011 16:36:32 +0200 Date: Thu, 12 May 2011 16:36:31 +0200 From: Jakub Jelinek To: gcc-patches@gcc.gnu.org Subject: [PATCH] Fix expansion of comparisons into signed type with 1-bit precision (PR middle-end/48973) Message-ID: <20110512143631.GI17079@tyan-ft48-01.lab.bos.redhat.com> Reply-To: Jakub Jelinek MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-IsSubscribed: yes 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 Hi! The read from a 1-bit signed bitfield initialized by a comparison is optimized into the comparison, which has that 1-bit signed bitfield comparison. Unfortunately that is still expanded as setting the result to 0 resp. 1 instead of this case 0 resp. -1 QImode pseudo, which is then sign extended into SImode for the comparison. Fixed by special casing expansion in that case. I think it is rare enough we can just ignore the fold_single_bit_test optimization in that case, rather than having two versions thereof. Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/4.6? 2011-05-12 Jakub Jelinek PR middle-end/48973 * expr.c (expand_expr_real_2) : If do_store_flag failed and the comparison has a single bit signed type, use constm1_rtx instead of const1_rtx for true value. (do_store_flag): If ops->type is single bit signed type, disable signel bit test optimization and pass -1 instead of 1 as last parameter to emit_store_flag_force. * gcc.c-torture/execute/pr48973-1.c: New test. * gcc.c-torture/execute/pr48973-2.c: New test. Jakub --- gcc/expr.c.jj 2011-05-11 19:39:04.000000000 +0200 +++ gcc/expr.c 2011-05-12 10:46:52.000000000 +0200 @@ -8105,7 +8105,10 @@ expand_expr_real_2 (sepops ops, rtx targ op1 = gen_label_rtx (); jumpifnot_1 (code, treeop0, treeop1, op1, -1); - emit_move_insn (target, const1_rtx); + if (TYPE_PRECISION (type) == 1 && !TYPE_UNSIGNED (type)) + emit_move_insn (target, constm1_rtx); + else + emit_move_insn (target, const1_rtx); emit_label (op1); return target; @@ -10050,7 +10053,8 @@ do_store_flag (sepops ops, rtx target, e if ((code == NE || code == EQ) && TREE_CODE (arg0) == BIT_AND_EXPR && integer_zerop (arg1) - && integer_pow2p (TREE_OPERAND (arg0, 1))) + && integer_pow2p (TREE_OPERAND (arg0, 1)) + && (TYPE_PRECISION (ops->type) != 1 || TYPE_UNSIGNED (ops->type))) { tree type = lang_hooks.types.type_for_mode (mode, unsignedp); return expand_expr (fold_single_bit_test (loc, @@ -10070,7 +10074,9 @@ do_store_flag (sepops ops, rtx target, e /* Try a cstore if possible. */ return emit_store_flag_force (target, code, op0, op1, - operand_mode, unsignedp, 1); + operand_mode, unsignedp, + (TYPE_PRECISION (ops->type) == 1 + && !TYPE_UNSIGNED (ops->type)) ? -1 : 1); } --- gcc/testsuite/gcc.c-torture/execute/pr48973-1.c.jj 2011-05-12 10:53:49.000000000 +0200 +++ gcc/testsuite/gcc.c-torture/execute/pr48973-1.c 2011-05-12 10:53:12.000000000 +0200 @@ -0,0 +1,20 @@ +/* PR middle-end/48973 */ + +extern void abort (void); +struct S { int f : 1; } s; +int v = -1; + +void +foo (unsigned int x) +{ + if (x != -1U) + abort (); +} + +int +main () +{ + s.f = (v & 1) > 0; + foo (s.f); + return 0; +} --- gcc/testsuite/gcc.c-torture/execute/pr48973-2.c.jj 2011-05-12 10:53:52.000000000 +0200 +++ gcc/testsuite/gcc.c-torture/execute/pr48973-2.c 2011-05-12 10:53:37.000000000 +0200 @@ -0,0 +1,14 @@ +/* PR middle-end/48973 */ + +extern void abort (void); +struct S { int f : 1; } s; +int v = -1; + +int +main () +{ + s.f = v < 0; + if ((unsigned int) s.f != -1U) + abort (); + return 0; +}