| Message ID | 563B7A32.7010209@acm.org |
|---|---|
| State | New |
| Headers | show |
Hi! On Thu, 5 Nov 2015 10:48:02 -0500, Nathan Sidwell <nathan@acm.org> wrote: > On 11/04/15 05:02, Bernd Schmidt wrote: > > On 11/02/2015 02:56 PM, Nathan Sidwell wrote: > >> On 10/28/15 14:40, Nathan Sidwell wrote: > >>> Richard, > >>> this patch adds folding for the new GOACC_DIM_POS and GOACC_DIM_SIZE > >>> internal > >>> functions. IIUC gimple_fold_call is the right place to add this. > >>> > >>> The size of a compute dimension is very often a compile-time > >>> constant. On the > >>> host, in particular it's 1, which means we can deduce the POS must be > >>> zero. > This is what I committed, using the helpers I recently added. (I realized we can > only get here for functions with the oacc attribute already set) > --- gimple-fold.c (revision 229809) > +++ gimple-fold.c (working copy) > +/* Transform IFN_GOACC_DIM_SIZE and IFN_GOACC_DIM_POS internal > + function calls to constants, where possible. */ > + > +static tree > +fold_internal_goacc_dim (const gimple *call) > +{ > + int axis = get_oacc_ifn_dim_arg (call); > + int size = get_oacc_fn_dim_size (current_function_decl, axis); > + bool is_pos = gimple_call_internal_fn (call) == IFN_GOACC_DIM_POS; > + tree result = NULL_TREE; > + > + /* If the size is 1, or we only want the size and it is not dynamic, > + we know the answer. */ > + if (size == 1 || (!is_pos && size)) > + { > + tree type = TREE_TYPE (gimple_call_lhs (call)); > + result = build_int_cst (type, size - is_pos); > + } > + > + return result; > +} > @@ -3106,6 +3129,10 @@ gimple_fold_call (gimple_stmt_iterator * > return true; > } > break; > + case IFN_GOACC_DIM_SIZE: > + case IFN_GOACC_DIM_POS: > + result = fold_internal_goacc_dim (stmt); > + break; Merging this into gomp-4_0-branch, we'd run into a lot of regressions (for OpenACC kernels construct), for example: [...]/source-gcc/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c: In function 'main._omp_fn.0': [...]/source-gcc/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c:8:0: internal compiler error: Segmentation fault 0xac387f crash_signal [...]/source-gcc/gcc/toplev.c:336 0x9b8399 tree_int_cst_elt_check [...]/source-gcc/gcc/tree.h:3129 0x9b8399 get_oacc_fn_dim_size(tree_node*, int) [...]/source-gcc/gcc/omp-low.c:12630 0x86c530 fold_internal_goacc_dim [...]/source-gcc/gcc/gimple-fold.c:2917 0x86c530 gimple_fold_call [...]/source-gcc/gcc/gimple-fold.c:3134 0x86dfe4 fold_stmt_1 [...]/source-gcc/gcc/gimple-fold.c:3702 0xbf9953 execute [...]/source-gcc/gcc/tree-ssa-forwprop.c:2310 The dims in gcc/omp-low.c:get_oacc_fn_dim_size don't have values set, so the "TREE_INT_CST_LOW (TREE_VALUE (dims))" fails. I have not analyzed what exactly is going wrong; I just figured out that it's related to the IFN_GOACC_DIM_POS without LHS usage that Tom introduced in gomp-4_0-branch r228735 for OpenACC kernels to "neuter gang-single code in gang-redundant mode", <http://news.gmane.org/find-root.php?message_id=%3C561C1336.2050401%40mentor.com%3E>. So, in r229948 I merged Nathan's trunk r229816 into gomp-4_0-branch with an additional hack as indicated ("++" prefix) by the following three-way diff: commit b421a6415fc223866bc97f8248a1fbd0a524505e Merge: 7a6eb6b b0ccb4e Author: tschwinge <tschwinge@138bc75d-0d04-0410-961f-82ee72b054a4> Date: Sun Nov 8 13:49:46 2015 +0000 svn merge -r 229814:229816 svn+ssh://gcc.gnu.org/svn/gcc/trunk git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gomp-4_0-branch@229948 138bc75d-0d04-0410-961f-82ee72b054a4 gcc/ChangeLog | 6 ++++++ gcc/gimple-fold.c | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+) diff --cc gcc/gimple-fold.c index c9b9593,45840af..869c6c2 --- gcc/gimple-fold.c +++ gcc/gimple-fold.c @@@ -2906,6 -2907,28 +2907,34 @@@ gimple_fold_builtin (gimple_stmt_iterat return false; } + /* Transform IFN_GOACC_DIM_SIZE and IFN_GOACC_DIM_POS internal + function calls to constants, where possible. */ + + static tree + fold_internal_goacc_dim (const gimple *call) + { ++ /* TODO. There is something going wrong here, for the gang_single ++ IFN_GOACC_DIM_POS without LHS, generated in gcc/omp-low.c:lower_omp_target ++ for is_oacc_kernels (see gomp-4_0-branch r228735). */ ++ if (gimple_call_lhs (call) == NULL_TREE) ++ return NULL_TREE; ++ + int axis = get_oacc_ifn_dim_arg (call); + int size = get_oacc_fn_dim_size (current_function_decl, axis); + bool is_pos = gimple_call_internal_fn (call) == IFN_GOACC_DIM_POS; + tree result = NULL_TREE; + + /* If the size is 1, or we only want the size and it is not dynamic, + we know the answer. */ + if (size == 1 || (!is_pos && size)) + { + tree type = TREE_TYPE (gimple_call_lhs (call)); + result = build_int_cst (type, size - is_pos); + } + + return result; + } + /* Return true if ARG0 CODE ARG1 in infinite signed precision operation doesn't fit into TYPE. The test for overflow should be regardless of -fwrapv, and even for unsigned types. */ Grüße Thomas
On 08/11/15 15:04, Thomas Schwinge wrote: > Hi! > > On Thu, 5 Nov 2015 10:48:02 -0500, Nathan Sidwell<nathan@acm.org> wrote: >> >On 11/04/15 05:02, Bernd Schmidt wrote: >>> > >On 11/02/2015 02:56 PM, Nathan Sidwell wrote: >>>> > >>On 10/28/15 14:40, Nathan Sidwell wrote: >>>>> > >>>Richard, >>>>> > >>>this patch adds folding for the new GOACC_DIM_POS and GOACC_DIM_SIZE >>>>> > >>>internal >>>>> > >>>functions. IIUC gimple_fold_call is the right place to add this. >>>>> > >>> >>>>> > >>>The size of a compute dimension is very often a compile-time >>>>> > >>>constant. On the >>>>> > >>>host, in particular it's 1, which means we can deduce the POS must be >>>>> > >>>zero. >> >This is what I committed, using the helpers I recently added. (I realized we can >> >only get here for functions with the oacc attribute already set) >> >--- gimple-fold.c (revision 229809) >> >+++ gimple-fold.c (working copy) >> >+/* Transform IFN_GOACC_DIM_SIZE and IFN_GOACC_DIM_POS internal >> >+ function calls to constants, where possible. */ >> >+ >> >+static tree >> >+fold_internal_goacc_dim (const gimple *call) >> >+{ >> >+ int axis = get_oacc_ifn_dim_arg (call); >> >+ int size = get_oacc_fn_dim_size (current_function_decl, axis); >> >+ bool is_pos = gimple_call_internal_fn (call) == IFN_GOACC_DIM_POS; >> >+ tree result = NULL_TREE; >> >+ >> >+ /* If the size is 1, or we only want the size and it is not dynamic, >> >+ we know the answer. */ >> >+ if (size == 1 || (!is_pos && size)) >> >+ { >> >+ tree type = TREE_TYPE (gimple_call_lhs (call)); >> >+ result = build_int_cst (type, size - is_pos); >> >+ } >> >+ >> >+ return result; >> >+} >> >@@ -3106,6 +3129,10 @@ gimple_fold_call (gimple_stmt_iterator * >> > return true; >> > } >> > break; >> >+ case IFN_GOACC_DIM_SIZE: >> >+ case IFN_GOACC_DIM_POS: >> >+ result = fold_internal_goacc_dim (stmt); >> >+ break; > Merging this into gomp-4_0-branch, we'd run into a lot of regressions > (for OpenACC kernels construct), for example: > > [...]/source-gcc/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c: In function 'main._omp_fn.0': > [...]/source-gcc/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c:8:0: internal compiler error: Segmentation fault > 0xac387f crash_signal > [...]/source-gcc/gcc/toplev.c:336 > 0x9b8399 tree_int_cst_elt_check > [...]/source-gcc/gcc/tree.h:3129 > 0x9b8399 get_oacc_fn_dim_size(tree_node*, int) > [...]/source-gcc/gcc/omp-low.c:12630 > 0x86c530 fold_internal_goacc_dim > [...]/source-gcc/gcc/gimple-fold.c:2917 > 0x86c530 gimple_fold_call > [...]/source-gcc/gcc/gimple-fold.c:3134 > 0x86dfe4 fold_stmt_1 > [...]/source-gcc/gcc/gimple-fold.c:3702 > 0xbf9953 execute > [...]/source-gcc/gcc/tree-ssa-forwprop.c:2310 > > The dims in gcc/omp-low.c:get_oacc_fn_dim_size don't have values set, so > the "TREE_INT_CST_LOW (TREE_VALUE (dims))" fails. I have not analyzed > what exactly is going wrong; I just figured out that it's related to the > IFN_GOACC_DIM_POS without LHS usage that Tom introduced in > gomp-4_0-branch r228735 for OpenACC kernels to "neuter gang-single code > in gang-redundant mode", > <http://news.gmane.org/find-root.php?message_id=%3C561C1336.2050401%40mentor.com%3E>. I've just removed that ( https://gcc.gnu.org/ml/gcc-patches/2015-11/msg00847.html ). Thanks, - Tom
2015-11-05 Nathan Sidwell <nathan@codesourcery.com> * gimple-fold.c: Include omp-low.h. (fold_internal_goacc_dim): New. (gimple_fold_call): Call it. Index: gimple-fold.c =================================================================== --- gimple-fold.c (revision 229809) +++ gimple-fold.c (working copy) @@ -52,6 +52,7 @@ along with GCC; see the file COPYING3. #include "gimple-match.h" #include "gomp-constants.h" #include "optabs-query.h" +#include "omp-low.h" /* Return true when DECL can be referenced from current unit. @@ -2906,6 +2907,28 @@ gimple_fold_builtin (gimple_stmt_iterato return false; } +/* Transform IFN_GOACC_DIM_SIZE and IFN_GOACC_DIM_POS internal + function calls to constants, where possible. */ + +static tree +fold_internal_goacc_dim (const gimple *call) +{ + int axis = get_oacc_ifn_dim_arg (call); + int size = get_oacc_fn_dim_size (current_function_decl, axis); + bool is_pos = gimple_call_internal_fn (call) == IFN_GOACC_DIM_POS; + tree result = NULL_TREE; + + /* If the size is 1, or we only want the size and it is not dynamic, + we know the answer. */ + if (size == 1 || (!is_pos && size)) + { + tree type = TREE_TYPE (gimple_call_lhs (call)); + result = build_int_cst (type, size - is_pos); + } + + return result; +} + /* Return true if ARG0 CODE ARG1 in infinite signed precision operation doesn't fit into TYPE. The test for overflow should be regardless of -fwrapv, and even for unsigned types. */ @@ -3106,6 +3129,10 @@ gimple_fold_call (gimple_stmt_iterator * return true; } break; + case IFN_GOACC_DIM_SIZE: + case IFN_GOACC_DIM_POS: + result = fold_internal_goacc_dim (stmt); + break; case IFN_UBSAN_CHECK_ADD: subcode = PLUS_EXPR; break;