From 94d145bf5bb4260cb02d43434ab48eb6d6ffe0cd Mon Sep 17 00:00:00 2001 From: Thomas Koenig Date: Thu, 7 Jun 2012 11:11:55 +0000 Subject: re PR fortran/52861 ((missed optimisation) missed transformation to memset with -O3) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 2012-06-07 Thomas König PR fortran/52861 * frontend-passes (empty_string): Add prototype. (optimize_assignment): Set the length of an empty string constant to zero. 2012-06-07 Thomas König PR fortran/52861 * gfortran.dg/string_assign_1.f90: New test case. From-SVN: r188300 --- gcc/fortran/ChangeLog | 7 +++++++ gcc/fortran/frontend-passes.c | 14 ++++++++++---- 2 files changed, 17 insertions(+), 4 deletions(-) (limited to 'gcc/fortran') diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog index b3342ab..c882a41 100644 --- a/gcc/fortran/ChangeLog +++ b/gcc/fortran/ChangeLog @@ -1,3 +1,10 @@ +2012-06-07 Thomas König + + PR fortran/52861 + * frontend-passes (empty_string): Add prototype. + (optimize_assignment): Set the length of an empty string + constant to zero. + 2012-06-04 Tobias Burnus PR fortran/50619 diff --git a/gcc/fortran/frontend-passes.c b/gcc/fortran/frontend-passes.c index 40ca074..4fd24c2 100644 --- a/gcc/fortran/frontend-passes.c +++ b/gcc/fortran/frontend-passes.c @@ -1,5 +1,5 @@ /* Pass manager for Fortran front end. - Copyright (C) 2010, 2011 Free Software Foundation, Inc. + Copyright (C) 2010, 2011, 2012 Free Software Foundation, Inc. Contributed by Thomas König. This file is part of GCC. @@ -37,6 +37,7 @@ static bool optimize_comparison (gfc_expr *, gfc_intrinsic_op); static bool optimize_trim (gfc_expr *); static bool optimize_lexical_comparison (gfc_expr *); static void optimize_minmaxloc (gfc_expr **); +static bool empty_string (gfc_expr *e); /* How deep we are inside an argument list. */ @@ -734,10 +735,15 @@ optimize_assignment (gfc_code * c) lhs = c->expr1; rhs = c->expr2; - /* Optimize away a = trim(b), where a is a character variable. */ - if (lhs->ts.type == BT_CHARACTER) - remove_trim (rhs); + { + /* Optimize away a = trim(b), where a is a character variable. */ + remove_trim (rhs); + + /* Replace a = ' ' by a = '' to optimize away a memcpy. */ + if (empty_string(rhs)) + rhs->value.character.length = 0; + } if (lhs->rank > 0 && gfc_check_dependency (lhs, rhs, true) == 0) optimize_binop_array_assignment (c, &rhs, false); -- cgit v1.1