From: Thomas Koenig Date: Fri, 3 Dec 2010 10:35:12 +0000 (+0000) Subject: re PR fortran/45159 (Unnecessary temporaries) X-Git-Tag: releases/gcc-4.6.0~2164 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8976d513cc7e285ef043df4766efada449216eec;p=thirdparty%2Fgcc.git re PR fortran/45159 (Unnecessary temporaries) 2010-12-02 Thomas Koenig PR fortran/45159 * dependency.c (check_section_vs_section): Pre-calculate the relationship between the strides and the relationship between the start values. Use an integer constant one for that purpose. Forward dependencies for positive strides apply for where the lhs start <= rhs start and lhs stride <= rhs stride and vice versa for negative stride. No need to compare end expressions in either case (assume no bounds violation). 2010-12-02 Thomas Koenig PR fortran/45159 * gfortran.dg/dependency_38.f90: New test. From-SVN: r167413 --- diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog index ae2f033ae6df..36b2ef26d1d8 100644 --- a/gcc/fortran/ChangeLog +++ b/gcc/fortran/ChangeLog @@ -1,3 +1,15 @@ +2010-12-02 Thomas Koenig + + PR fortran/45159 + * dependency.c (check_section_vs_section): Pre-calculate + the relationship between the strides and the relationship + between the start values. Use an integer constant one for + that purpose. + Forward dependencies for positive strides apply for where + the lhs start <= rhs start and lhs stride <= rhs stride + and vice versa for negative stride. No need to compare + end expressions in either case (assume no bounds violation). + 2010-12-02 Thomas Koenig * trans-array.c (gfc_could_be_alias): Handle BT_CLASS diff --git a/gcc/fortran/dependency.c b/gcc/fortran/dependency.c index 40969f6e2d40..77e8df72b68d 100644 --- a/gcc/fortran/dependency.c +++ b/gcc/fortran/dependency.c @@ -1071,8 +1071,10 @@ check_section_vs_section (gfc_array_ref *l_ar, gfc_array_ref *r_ar, int n) gfc_expr *r_stride; gfc_expr *r_lower; gfc_expr *r_upper; + gfc_expr *one_expr; int r_dir; - bool identical_strides; + int stride_comparison; + int start_comparison; /* If they are the same range, return without more ado. */ if (gfc_is_same_range (l_ar, r_ar, n, 0)) @@ -1126,22 +1128,24 @@ check_section_vs_section (gfc_array_ref *l_ar, gfc_array_ref *r_ar, int n) if (l_dir == 0 || r_dir == 0) return GFC_DEP_OVERLAP; - /* Determine if the strides are equal. */ + /* Determine the relationship between the strides. Set stride_comparison to + -2 if the dependency cannot be determined + -1 if l_stride < r_stride + 0 if l_stride == r_stride + 1 if l_stride > r_stride + as determined by gfc_dep_compare_expr. */ - if (l_stride) - { - if (r_stride) - identical_strides = gfc_dep_compare_expr (l_stride, r_stride) == 0; - else - identical_strides = gfc_expr_is_one (l_stride, 0) == 1; - } + one_expr = gfc_get_int_expr (gfc_index_integer_kind, NULL, 1); + + stride_comparison = gfc_dep_compare_expr (l_stride ? l_stride : one_expr, + r_stride ? r_stride : one_expr); + + if (l_start && r_start) + start_comparison = gfc_dep_compare_expr (l_start, r_start); else - { - if (r_stride) - identical_strides = gfc_expr_is_one (r_stride, 0) == 1; - else - identical_strides = true; - } + start_comparison = -2; + + gfc_free (one_expr); /* Determine LHS upper and lower bounds. */ if (l_dir == 1) @@ -1237,61 +1241,60 @@ check_section_vs_section (gfc_array_ref *l_ar, gfc_array_ref *r_ar, int n) #undef IS_CONSTANT_INTEGER - /* Check for forward dependencies x:y vs. x+1:z. */ - if (l_dir == 1 && r_dir == 1 - && l_start && r_start && gfc_dep_compare_expr (l_start, r_start) == -1 - && l_end && r_end && gfc_dep_compare_expr (l_end, r_end) == -1) - { - if (identical_strides) - return GFC_DEP_FORWARD; - } + /* Check for forward dependencies x:y vs. x+1:z and x:y:z vs. x:y:z+1. */ - /* Check for forward dependencies x:y:-1 vs. x-1:z:-1. */ - if (l_dir == -1 && r_dir == -1 - && l_start && r_start && gfc_dep_compare_expr (l_start, r_start) == 1 - && l_end && r_end && gfc_dep_compare_expr (l_end, r_end) == 1) - { - if (identical_strides) - return GFC_DEP_FORWARD; - } + if (l_dir == 1 && r_dir == 1 && + (start_comparison == 0 || start_comparison == -1) + && (stride_comparison == 0 || stride_comparison == -1)) + return GFC_DEP_FORWARD; + /* Check for forward dependencies x:y:-1 vs. x-1:z:-1 and + x:y:-1 vs. x:y:-2. */ + if (l_dir == -1 && r_dir == -1 && + (start_comparison == 0 || start_comparison == 1) + && (stride_comparison == 0 || stride_comparison == 1)) + return GFC_DEP_FORWARD; - if (identical_strides) + if (stride_comparison == 0 || stride_comparison == -1) { - if (l_start && IS_ARRAY_EXPLICIT (l_ar->as)) { - /* Check for a(low:y:s) vs. a(z:a:s) where a has a lower bound + /* Check for a(low:y:s) vs. a(z:x:s) or + a(low:y:s) vs. a(z:x:s+1) where a has a lower bound of low, which is always at least a forward dependence. */ if (r_dir == 1 && gfc_dep_compare_expr (l_start, l_ar->as->lower[n]) == 0) return GFC_DEP_FORWARD; + } + } - /* Check for a(high:y:-s) vs. a(z:a:-s) where a has a higher bound + if (stride_comparison == 0 || stride_comparison == 1) + { + if (l_start && IS_ARRAY_EXPLICIT (l_ar->as)) + { + + /* Check for a(high:y:-s) vs. a(z:x:-s) or + a(high:y:-s vs. a(z:x:-s-1) where a has a higher bound of high, which is always at least a forward dependence. */ if (r_dir == -1 && gfc_dep_compare_expr (l_start, l_ar->as->upper[n]) == 0) return GFC_DEP_FORWARD; } + } + + if (stride_comparison == 0) + { /* From here, check for backwards dependencies. */ - /* x:y vs. x+1:z. */ - if (l_dir == 1 && r_dir == 1 - && l_start && r_start - && gfc_dep_compare_expr (l_start, r_start) == 1 - && l_end && r_end - && gfc_dep_compare_expr (l_end, r_end) == 1) + /* x+1:y vs. x:z. */ + if (l_dir == 1 && r_dir == 1 && start_comparison == 1) return GFC_DEP_BACKWARD; - /* x:y:-1 vs. x-1:z:-1. */ - if (l_dir == -1 && r_dir == -1 - && l_start && r_start - && gfc_dep_compare_expr (l_start, r_start) == -1 - && l_end && r_end - && gfc_dep_compare_expr (l_end, r_end) == -1) + /* x-1:y:-1 vs. x:z:-1. */ + if (l_dir == -1 && r_dir == -1 && start_comparison == -1) return GFC_DEP_BACKWARD; } diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index e0769f5d8e21..10295b2cbd90 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2010-12-02 Thomas Koenig + + PR fortran/45159 + * gfortran.dg/dependency_38.f90: New test. + 2010-12-02 Ian Lance Taylor * lib/go.exp: New file. diff --git a/gcc/testsuite/gfortran.dg/dependency_38.f90 b/gcc/testsuite/gfortran.dg/dependency_38.f90 new file mode 100644 index 000000000000..60cb2ad1b7bd --- /dev/null +++ b/gcc/testsuite/gfortran.dg/dependency_38.f90 @@ -0,0 +1,14 @@ +! { dg-do compile } +! { dg-options "-Warray-temporaries" } +! PR 45159 - No temporary should be created for this. +program main + integer a(100) + a(10:16:2) = a(10:16:2) + a(10:16:2) = a(10:19:3) + a(10:18:2) = a(12:20:2) + a(1:10) = a(2:20:2) + a(16:10:-2) = a(16:10:-2) + a(19:10:-1) = a(19:1:-2) + a(19:10:-1) = a(18:9:-1) + a(19:11:-1) = a(18:2:-2) +end program main