From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 3933 invoked by alias); 13 Dec 2010 17:25:19 -0000 Received: (qmail 3921 invoked by uid 22791); 13 Dec 2010 17:25:18 -0000 X-SWARE-Spam-Status: No, hits=-2.8 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 13 Dec 2010 17:25:10 +0000 From: "amonakov at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/46758] [4.5/4.6 Regression] -fgraphite-identity produces wrong code when using 64bit constants X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: middle-end X-Bugzilla-Keywords: wrong-code X-Bugzilla-Severity: normal X-Bugzilla-Who: amonakov at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.5.2 X-Bugzilla-Changed-Fields: Status AssignedTo Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Date: Mon, 13 Dec 2010 17:25:00 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2010-12/txt/msg01443.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46758 Alexander Monakov changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |NEW AssignedTo|amonakov at gcc dot gnu.org |unassigned at gcc dot | |gnu.org --- Comment #4 from Alexander Monakov 2010-12-13 17:24:59 UTC --- Ouch. The "obvious" fix: diff --git a/gcc/graphite-sese-to-poly.c b/gcc/graphite-sese-to-poly.c index 5036fba..8fda288 100644 --- a/gcc/graphite-sese-to-poly.c +++ b/gcc/graphite-sese-to-poly.c @@ -626,16 +626,9 @@ scan_tree_for_params_int (tree cst, ppl_Linear_Expression_t expr, mpz_t k) { mpz_t val; ppl_Coefficient_t coef; - int v = int_cst_value (cst); mpz_init (val); - mpz_set_si (val, 0); - - /* Necessary to not get "-1 = 2^n - 1". */ - if (v < 0) - mpz_sub_ui (val, val, -v); - else - mpz_add_ui (val, val, v); + tree_int_to_gmp (cst, val); mpz_mul (val, val, k); ppl_new_Coefficient (&coef); Makes Graphite fail most tests because this scanning machinery curiously depends on signed/unsigned conversions/overflow. For example, when an IV upper bound N-1 is expressed as (unsigned)(N + 0xFFFFFFFFU), the patch makes Graphite actually generate N + 0xFFFFFFFFU as upper bound in the corresponding PPL expression: (gdb) p nb_iters $2 = (tree) 0x7ffff7ff9ee0 (gdb) pt unit size align 32 symtab 0 alias set -1 canonical type 0x7ffff7ed0540 precision 32 min max pointer_to_this > arg 0 arg 0 visited var def_stmt GIMPLE_NOP version 6>> arg 1 constant 4294967295>> (gdb) call debug_ppl_linear_expr (ub_expr) 1 5 0 0 1 0 4294967295 I don't know how to fix this; thus, unassigning. Sorry.