From: Kwok Cheung Yeung Date: Mon, 1 Mar 2021 22:15:30 +0000 (-0800) Subject: openmp: Scale type precision of collapsed iterator variable X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f3d77a2a8530627ebeacf2a53ef94be4d3319b3e;p=thirdparty%2Fgcc.git openmp: Scale type precision of collapsed iterator variable This sets the type precision of the collapsed iterator variable to the sum of the precision of the collapsed loop variables, up to a maximum of sizeof(long long) (i.e. 64-bits). 2021-03-01 Kwok Cheung Yeung gcc/ * omp-expand.cc (expand_oacc_for): Convert .tile variable to diff_type before multiplying. * omp-general.cc (omp_extract_for_data): Use accumulated precision of all collapsed for-loops as precision of iteration variable, up to the precision of a long long. libgomp/ * testsuite/libgomp.c-c++-common/collapse-4.c: New. * testsuite/libgomp.fortran/collapse5.f90: New. --- diff --git a/gcc/ChangeLog.omp b/gcc/ChangeLog.omp index 1052b364689b..712473c6378e 100644 --- a/gcc/ChangeLog.omp +++ b/gcc/ChangeLog.omp @@ -1,3 +1,11 @@ +2021-03-01 Kwok Cheung Yeung + + * omp-expand.cc (expand_oacc_for): Convert .tile variable to + diff_type before multiplying. + * omp-general.cc (omp_extract_for_data): Use accumulated precision + of all collapsed for-loops as precision of iteration variable, up + to the precision of a long long. + 2021-02-26 Andrew Stubbs * dwarf2out.cc (gen_subprogram_die): Replace existing low/high PC diff --git a/gcc/omp-expand.cc b/gcc/omp-expand.cc index e113231e52d4..316020772f2f 100644 --- a/gcc/omp-expand.cc +++ b/gcc/omp-expand.cc @@ -7702,7 +7702,10 @@ expand_oacc_for (struct omp_region *region, struct omp_for_data *fd) tile_size = create_tmp_var (diff_type, ".tile_size"); expr = build_int_cst (diff_type, 1); for (int ix = 0; ix < fd->collapse; ix++) - expr = fold_build2 (MULT_EXPR, diff_type, counts[ix].tile, expr); + { + tree tile = fold_convert (diff_type, counts[ix].tile); + expr = fold_build2 (MULT_EXPR, diff_type, tile, expr); + } expr = force_gimple_operand_gsi (&gsi, expr, true, NULL_TREE, true, GSI_SAME_STMT); ass = gimple_build_assign (tile_size, expr); diff --git a/gcc/omp-general.cc b/gcc/omp-general.cc index a406c578f331..8c7dce20dfb4 100644 --- a/gcc/omp-general.cc +++ b/gcc/omp-general.cc @@ -375,6 +375,7 @@ omp_extract_for_data (gomp_for *for_stmt, struct omp_for_data *fd, fd->non_rect = true; } } + int accum_iter_precision = 0; for (i = 0; i < cnt; i++) { if (i == 0 @@ -457,12 +458,28 @@ omp_extract_for_data (gomp_for *for_stmt, struct omp_for_data *fd, { if (fd->collapse == 1 && !fd->tiling) iter_type = TREE_TYPE (loop->v); - else if (i == 0 - || TYPE_PRECISION (iter_type) - < TYPE_PRECISION (TREE_TYPE (loop->v))) - iter_type - = build_nonstandard_integer_type - (TYPE_PRECISION (TREE_TYPE (loop->v)), 1); + else + { + int loop_precision = TYPE_PRECISION (TREE_TYPE (loop->v)); + int iter_type_precision = 0; + const int max_accum_precision + = TYPE_PRECISION (long_long_unsigned_type_node); + + accum_iter_precision += loop_precision; + + if (i == 0 + || (loop_precision >= max_accum_precision + && loop_precision >= TYPE_PRECISION (iter_type))) + iter_type_precision = loop_precision; + else if (TYPE_PRECISION (iter_type) < max_accum_precision) + iter_type_precision + = MIN (1 << ceil_log2 (accum_iter_precision), + max_accum_precision); + + if (iter_type_precision) + iter_type = build_nonstandard_integer_type + (iter_type_precision, 1); + } } else if (iter_type != long_long_unsigned_type_node) { diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp index 4bf75fd6861a..37795c1554e4 100644 --- a/libgomp/ChangeLog.omp +++ b/libgomp/ChangeLog.omp @@ -1,3 +1,8 @@ +2021-03-01 Kwok Cheung Yeung + + * testsuite/libgomp.c-c++-common/collapse-4.c: New. + * testsuite/libgomp.fortran/collapse5.f90: New. + 2021-02-23 Andrew Stubbs * plugin/plugin-nvptx.c (GOMP_OFFLOAD_alloc): Remove early call to diff --git a/libgomp/testsuite/libgomp.c-c++-common/collapse-4.c b/libgomp/testsuite/libgomp.c-c++-common/collapse-4.c new file mode 100644 index 000000000000..c0af29f54639 --- /dev/null +++ b/libgomp/testsuite/libgomp.c-c++-common/collapse-4.c @@ -0,0 +1,23 @@ +/* { dg-do run } */ + +#include + +int +main (void) +{ + int i, j; + int count = 0; + + #pragma omp parallel for collapse(2) + for (i = 0; i < 80000; i++) + for (j = 0; j < 80000; j++) + if (i == 66666 && j == 77777) + /* In the collapsed loop space, this is iteration + 66666*80000+77777==5,333,357,777. If the type of the iterator + for the collapsed loop is only a 32-bit unsigned int, then this + iteration will exceed its maximum range and be skipped. */ + count++; + + if (count != 1) + abort (); +} diff --git a/libgomp/testsuite/libgomp.fortran/collapse5.f90 b/libgomp/testsuite/libgomp.fortran/collapse5.f90 new file mode 100644 index 000000000000..5632d9bab020 --- /dev/null +++ b/libgomp/testsuite/libgomp.fortran/collapse5.f90 @@ -0,0 +1,23 @@ +! { dg-do run } + +program collapse5 + implicit none + + integer :: i, j + integer :: count = 0 + + !$omp parallel do collapse (2) + do i = 1, 80000 + do j = 1, 80000 + if (i .eq. 66666 .and. j .eq. 77777) then + ! In the collapsed loop space, this is iteration + ! 66666*80000+77777==5,333,357,777. If the type of the iterator + ! for the collapsed loop is only a 32-bit unsigned int, then this + ! iteration will exceed its maximum range and be skipped. + count = count + 1 + end if + end do + end do + + if (count .ne. 1) stop 1 +end