From patchwork Sun Aug 1 22:10:11 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Koenig X-Patchwork-Id: 60494 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 0F27C1007D2 for ; Mon, 2 Aug 2010 08:10:31 +1000 (EST) Received: (qmail 27182 invoked by alias); 1 Aug 2010 22:10:28 -0000 Received: (qmail 27166 invoked by uid 22791); 1 Aug 2010 22:10:23 -0000 X-SWARE-Spam-Status: No, hits=-1.7 required=5.0 tests=AWL, BAYES_00, RCVD_IN_DNSWL_NONE, T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from smtp5.netcologne.de (HELO smtp5.netcologne.de) (194.8.194.25) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sun, 01 Aug 2010 22:10:16 +0000 Received: from [192.168.0.196] (xdsl-213-168-108-245.netcologne.de [213.168.108.245]) by smtp5.netcologne.de (Postfix) with ESMTP id 6A8FF40CDBE; Mon, 2 Aug 2010 00:10:12 +0200 (CEST) Subject: Re: [patch, fortran] Follow references in dependency checking From: Thomas Koenig To: Tobias Burnus Cc: fortran@gcc.gnu.org, gcc-patches@gcc.gnu.org In-Reply-To: <4C55B5F2.8030609@net-b.de> References: <1280671076.3631.5.camel@linux-fd1f.site> <4C55B5F2.8030609@net-b.de> Date: Mon, 02 Aug 2010 00:10:11 +0200 Message-ID: <1280700611.3631.17.camel@linux-fd1f.site> Mime-Version: 1.0 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 Tobias Burnus wrote: Thanks a lot for your comments! > Thomas Koenig write: > > here's a patch which improves dependency checking. Both substring and > > array references are followed with this, so we can also avoid using > > temporaries for array expressions like > > > > a(i(1):i(2)) = a(i(1):i(2)) + b(i(1):i(2)) > > a(c%i:c%j) = a(c%i:c%j) + b(c%k:c%m) > > > > String references are also handled, so expressions like > > c(1:2) == c(1:2) can now be removed. See the test cases. > > > > Regression-tested on x86_64-unknown-linux-gnu. OK for trunk? > > > > @@ -402,10 +403,9 @@ optimize_equality (gfc_expr *e, bool equal) > TODO: Handle cases with identical refs. */ > > > That's obsolete. Can you replace it by a note that the ts != > REAL/COMPLEX check is to allow forf NAN checks? Done. > > + if (l_start == NULL) > + { > + if (r_start == NULL || gfc_expr_is_one (r_start, 0)) > + goto end_check; > + } > + else if (r_start == NULL) > + { > + if (gfc_expr_is_one (l_start, 0)) > + goto end_check; > + } > + else if (gfc_dep_compare_expr (l_start, r_start) != 0) > + return false; > + > + end_check: > > > The inner "if"s do not make sense. If the inner condition is true, one > jumps to "end_check"; if it is false, one falls through to "end_check". This was also wrong. Thanks for catching this! Fortunately, it turns out that I don't need to bother with all the NULL checks, that is taken care of before. I've removed that function again. This would also have introduced some regressions, for which I have added an additional test case (which makes sure that comparisons are still used for some things). > + while ((numref = (r1 != NULL) + (r2 != NULL)) > 0) > + { > + > + > That's ugly. Can't you simply use the following? Changed to something more becoming. You were right that this was ugly :-) Currently regtesting. OK if this passes? Thomas 2010-08-01 Thomas Koenig PR fortran/36854 * dependency.h: Add prototype for gfc_are_identical_variables. * frontend-passes.c: Include depencency.h. (optimimize_equality): Use gfc_are_identical_variables. * dependency.c (identical_array_ref): New function. (gfc_are_identical_variables): New function. (gfc_deb_compare_expr): Use gfc_are_identical_variables. * dependency.c (gfc_check_section_vs_section). Rename gfc_ prefix from statc function. (check_section_vs_section): Change arguments to gfc_array_ref, adjust function body accordingly. 2010-08-01 Thomas Koenig PR fortran/36854 * gfortran.dg/character_comparison_2.f90: New test. * gfortran.dg/character_comparison_3.f90: New test. * gfortran.dg/dependency_28.f90: New test. Index: frontend-passes.c =================================================================== --- frontend-passes.c (Revision 162585) +++ frontend-passes.c (Arbeitskopie) @@ -23,6 +23,7 @@ along with GCC; see the file COPYING3. If not see #include "gfortran.h" #include "arith.h" #include "flags.h" +#include "dependency.h" /* Forward declarations. */ @@ -398,14 +399,13 @@ optimize_equality (gfc_expr *e, bool equal) return true; } - /* Check for direct comparison between identical variables. - TODO: Handle cases with identical refs. */ + /* Check for direct comparison between identical variables. Don't compare + REAL or COMPLEX because of NaN checks. */ if (op1->expr_type == EXPR_VARIABLE && op2->expr_type == EXPR_VARIABLE - && op1->symtree == op2->symtree - && op1->ref == NULL && op2->ref == NULL && op1->ts.type != BT_REAL && op2->ts.type != BT_REAL - && op1->ts.type != BT_COMPLEX && op2->ts.type !=BT_COMPLEX) + && op1->ts.type != BT_COMPLEX && op2->ts.type !=BT_COMPLEX + && gfc_are_identical_variables (op1, op2)) { /* Replace the expression by a constant expression. The typespec and where remains the way it is. */ Index: dependency.c =================================================================== --- dependency.c (Revision 162585) +++ dependency.c (Arbeitskopie) @@ -49,7 +49,11 @@ gfc_dependency; /* Macros */ #define IS_ARRAY_EXPLICIT(as) ((as->type == AS_EXPLICIT ? 1 : 0)) +/* Forward declarations */ +static gfc_dependency check_section_vs_section (gfc_array_ref *, + gfc_array_ref *, int); + /* Returns 1 if the expr is an integer constant value 1, 0 if it is not or def if the value could not be determined. */ @@ -67,7 +71,111 @@ gfc_expr_is_one (gfc_expr *expr, int def) return mpz_cmp_si (expr->value.integer, 1) == 0; } +/* Check if two array references are known to be identical. Calls + gfc_dep_compare_expr if necessary for comparing array indices. */ +static bool +identical_array_ref (gfc_array_ref *a1, gfc_array_ref *a2) +{ + int i; + + if (a1->type == AR_FULL && a2->type == AR_FULL) + return true; + + if (a1->type == AR_SECTION && a2->type == AR_SECTION) + { + gcc_assert (a1->dimen == a2->dimen); + + for ( i = 0; i < a1->dimen; i++) + { + /* TODO: Currently, we punt on an integer array as an index. */ + if (a1->dimen_type[i] != DIMEN_RANGE + || a2->dimen_type[i] != DIMEN_RANGE) + return false; + + if (check_section_vs_section (a1, a2, i) != GFC_DEP_EQUAL) + return false; + } + return true; + } + + if (a1->type == AR_ELEMENT && a2->type == AR_ELEMENT) + { + gcc_assert (a1->dimen == a2->dimen); + for (i = 0; i < a1->dimen; i++) + { + if (gfc_dep_compare_expr (a1->start[i], a2->start[i]) != 0) + return false; + } + return true; + } + return false; +} + + + +/* Return true for identical variables, checking for references if + necessary. Calls identical_array_ref for checking array sections. */ + +bool +gfc_are_identical_variables (gfc_expr *e1, gfc_expr *e2) +{ + gfc_ref *r1, *r2; + + if (e1->symtree->n.sym != e2->symtree->n.sym) + return false; + + r1 = e1->ref; + r2 = e2->ref; + + /* numref is + 0 if ar and br both are null pointers + 1 if exactly one of them is a null pointer + 2 if both of them are non-null. */ + + while (r1 != NULL || r2 != NULL) + { + + /* Assume the variables are not equal if one has a reference and the + other doesn't. + TODO: Handle full references like comparing a(:) to a. + */ + + if (r1 == NULL || r2 == NULL) + return false; + + if (r1->type != r2->type) + return false; + + switch (r1->type) + { + + case REF_ARRAY: + if (!identical_array_ref (&r1->u.ar, &r2->u.ar)) + return false; + + break; + + case REF_COMPONENT: + if (r1->u.c.component != r2->u.c.component) + return false; + break; + + case REF_SUBSTRING: + if (gfc_dep_compare_expr (r1->u.ss.start, r2->u.ss.start) != 0 + || gfc_dep_compare_expr (r1->u.ss.end, r2->u.ss.end) != 0) + return false; + break; + + default: + gfc_internal_error ("gfc_are_identical_variables: Bad type"); + } + r1 = r1->next; + r2 = r2->next; + } + return true; +} + /* Compare two values. Returns 0 if e1 == e2, -1 if e1 < e2, +1 if e1 > e2, and -2 if the relationship could not be determined. */ @@ -191,11 +299,10 @@ gfc_dep_compare_expr (gfc_expr *e1, gfc_expr *e2) return 1; case EXPR_VARIABLE: - if (e1->ref || e2->ref) + if (gfc_are_identical_variables (e1, e2)) + return 0; + else return -2; - if (e1->symtree->n.sym == e2->symtree->n.sym) - return 0; - return -2; case EXPR_OP: /* Intrinsic operators are the same if their operands are the same. */ @@ -882,9 +989,8 @@ gfc_check_dependency (gfc_expr *expr1, gfc_expr *e /* Determines overlapping for two array sections. */ static gfc_dependency -gfc_check_section_vs_section (gfc_ref *lref, gfc_ref *rref, int n) +check_section_vs_section (gfc_array_ref *l_ar, gfc_array_ref *r_ar, int n) { - gfc_array_ref l_ar; gfc_expr *l_start; gfc_expr *l_end; gfc_expr *l_stride; @@ -892,7 +998,6 @@ static gfc_dependency gfc_expr *l_upper; int l_dir; - gfc_array_ref r_ar; gfc_expr *r_start; gfc_expr *r_end; gfc_expr *r_stride; @@ -900,34 +1005,31 @@ static gfc_dependency gfc_expr *r_upper; int r_dir; - l_ar = lref->u.ar; - r_ar = rref->u.ar; - /* If they are the same range, return without more ado. */ - if (gfc_is_same_range (&l_ar, &r_ar, n, 0)) + if (gfc_is_same_range (l_ar, r_ar, n, 0)) return GFC_DEP_EQUAL; - l_start = l_ar.start[n]; - l_end = l_ar.end[n]; - l_stride = l_ar.stride[n]; + l_start = l_ar->start[n]; + l_end = l_ar->end[n]; + l_stride = l_ar->stride[n]; - r_start = r_ar.start[n]; - r_end = r_ar.end[n]; - r_stride = r_ar.stride[n]; + r_start = r_ar->start[n]; + r_end = r_ar->end[n]; + r_stride = r_ar->stride[n]; /* If l_start is NULL take it from array specifier. */ - if (NULL == l_start && IS_ARRAY_EXPLICIT (l_ar.as)) - l_start = l_ar.as->lower[n]; + if (NULL == l_start && IS_ARRAY_EXPLICIT (l_ar->as)) + l_start = l_ar->as->lower[n]; /* If l_end is NULL take it from array specifier. */ - if (NULL == l_end && IS_ARRAY_EXPLICIT (l_ar.as)) - l_end = l_ar.as->upper[n]; + if (NULL == l_end && IS_ARRAY_EXPLICIT (l_ar->as)) + l_end = l_ar->as->upper[n]; /* If r_start is NULL take it from array specifier. */ - if (NULL == r_start && IS_ARRAY_EXPLICIT (r_ar.as)) - r_start = r_ar.as->lower[n]; + if (NULL == r_start && IS_ARRAY_EXPLICIT (r_ar->as)) + r_start = r_ar->as->lower[n]; /* If r_end is NULL take it from array specifier. */ - if (NULL == r_end && IS_ARRAY_EXPLICIT (r_ar.as)) - r_end = r_ar.as->upper[n]; + if (NULL == r_end && IS_ARRAY_EXPLICIT (r_ar->as)) + r_end = r_ar->as->upper[n]; /* Determine whether the l_stride is positive or negative. */ if (!l_stride) @@ -1574,7 +1676,7 @@ gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref, gf if (lref->u.ar.dimen_type[n] == DIMEN_RANGE && rref->u.ar.dimen_type[n] == DIMEN_RANGE) - this_dep = gfc_check_section_vs_section (lref, rref, n); + this_dep = check_section_vs_section (&lref->u.ar, &rref->u.ar, n); else if (lref->u.ar.dimen_type[n] == DIMEN_ELEMENT && rref->u.ar.dimen_type[n] == DIMEN_RANGE) this_dep = gfc_check_element_vs_section (lref, rref, n); Index: dependency.h =================================================================== --- dependency.h (Revision 162585) +++ dependency.h (Arbeitskopie) @@ -43,3 +43,5 @@ int gfc_expr_is_one (gfc_expr *, int); int gfc_dep_resolver(gfc_ref *, gfc_ref *, gfc_reverse *); int gfc_are_equivalenced_arrays (gfc_expr *, gfc_expr *); +bool gfc_are_identical_variables (gfc_expr *, gfc_expr *); +