This patch adds support for rewriting variables marked up with the "oacc gangprivate" attributes in a target-dependent way in the oaccdevlow pass of the offload compiler.
This behaviour is controlled by a new target hook, TARGET_GOACC_ADJUST_GANGPRIVATE_DECL. This is conceptually similar to the existing TARGET_GOACC_EXPAND_ACCEL_VAR hook, but that one works too late in the compilation process for AMD GCN. The patch to set the "oacc gangprivate" attribute was posted upstream here: https://gcc.gnu.org/ml/gcc-patches/2018-08/msg00749.html A version of that is already present on the og9 branch. Julian ChangeLog gcc/ * omp-offload.c (convert.h): Include. (struct addr_expr_rewrite_info): Add struct. (rewrite_addr_expr): New function. (is_sync_builtin_call): New function. (execute_oacc_device_lower): Support rewriting gang-private variables using target hook, and fix up addr_expr nodes afterwards. * target.def (adjust_gangprivate_decl): New target hook. * doc/tm.texi.in (TARGET_GOACC_ADJUST_GANGPRIVATE_DECL): Document new target hook. * doc/tm.texi: Regenerate. --- gcc/ChangeLog.openacc | 13 +++++ gcc/doc/tm.texi | 4 ++ gcc/doc/tm.texi.in | 2 + gcc/omp-offload.c | 133 ++++++++++++++++++++++++++++++++++++++++++ gcc/target.def | 6 ++ 5 files changed, 158 insertions(+) diff --git a/gcc/ChangeLog.openacc b/gcc/ChangeLog.openacc index a22f07c817c..b1c627b394c 100644 --- a/gcc/ChangeLog.openacc +++ b/gcc/ChangeLog.openacc @@ -1,3 +1,16 @@ +2019-09-05 Julian Brown <jul...@codesourcery.com> + + * omp-offload.c (convert.h): Include. + (struct addr_expr_rewrite_info): Add struct. + (rewrite_addr_expr): New function. + (is_sync_builtin_call): New function. + (execute_oacc_device_lower): Support rewriting gang-private variables + using target hook, and fix up addr_expr nodes afterwards. + * target.def (adjust_gangprivate_decl): New target hook. + * doc/tm.texi.in (TARGET_GOACC_ADJUST_GANGPRIVATE_DECL): Document new + target hook. + * doc/tm.texi: Regenerate. + 2019-08-13 Julian Brown <jul...@codesourcery.com> * omp-oacc-kernels.c (add_wait): New function, split out of... diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi index 9b88498eb95..f3707c6abe3 100644 --- a/gcc/doc/tm.texi +++ b/gcc/doc/tm.texi @@ -6162,6 +6162,10 @@ memories. A return value of NULL indicates that the target does not handle this VAR_DECL, and normal RTL expanding is resumed. @end deftypefn +@deftypefn {Target Hook} void TARGET_GOACC_ADJUST_GANGPRIVATE_DECL (tree @var{var}) +Tweak variable declaration for a gang-private variable. +@end deftypefn + @deftypefn {Target Hook} bool TARGET_GOACC_EXPLODE_ARGS (void) Define this hook to TRUE if arguments to offload regions should be exploded, i.e. passed as true arguments rather than in an argument array. diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in index c9c4341a35f..cebadf4a502 100644 --- a/gcc/doc/tm.texi.in +++ b/gcc/doc/tm.texi.in @@ -4210,6 +4210,8 @@ address; but often a machine-dependent strategy can generate better code. @hook TARGET_GOACC_EXPAND_ACCEL_VAR +@hook TARGET_GOACC_ADJUST_GANGPRIVATE_DECL + @hook TARGET_GOACC_EXPLODE_ARGS @node Anchored Addresses diff --git a/gcc/omp-offload.c b/gcc/omp-offload.c index 1129b00511e..c94dc956d7e 100644 --- a/gcc/omp-offload.c +++ b/gcc/omp-offload.c @@ -52,6 +52,7 @@ along with GCC; see the file COPYING3. If not see #include "stringpool.h" #include "attribs.h" #include "cfgloop.h" +#include "convert.h" /* Describe the OpenACC looping structure of a function. The entire function is held in a 'NULL' loop. */ @@ -1570,6 +1571,78 @@ maybe_discard_oacc_function (tree decl) return false; } +struct addr_expr_rewrite_info +{ + gimple *stmt; + hash_set<tree> *adjusted_vars; + bool avoid_pointer_conversion; + bool modified; +}; + +static tree +rewrite_addr_expr (tree *tp, int *walk_subtrees, void *data) +{ + walk_stmt_info *wi = (walk_stmt_info *) data; + addr_expr_rewrite_info *info = (addr_expr_rewrite_info *) wi->info; + + if (TREE_CODE (*tp) == ADDR_EXPR) + { + tree arg = TREE_OPERAND (*tp, 0); + + if (info->adjusted_vars->contains (arg)) + { + if (info->avoid_pointer_conversion) + { + *tp = build_fold_addr_expr (arg); + info->modified = true; + *walk_subtrees = 0; + } + else + { + gimple_stmt_iterator gsi = gsi_for_stmt (info->stmt); + tree repl = build_fold_addr_expr (arg); + gimple *stmt1 + = gimple_build_assign (make_ssa_name (TREE_TYPE (repl)), repl); + tree conv = convert_to_pointer (TREE_TYPE (*tp), + gimple_assign_lhs (stmt1)); + gimple *stmt2 + = gimple_build_assign (make_ssa_name (TREE_TYPE (*tp)), conv); + gsi_insert_before (&gsi, stmt1, GSI_SAME_STMT); + gsi_insert_before (&gsi, stmt2, GSI_SAME_STMT); + *tp = gimple_assign_lhs (stmt2); + info->modified = true; + *walk_subtrees = 0; + } + } + } + + return NULL_TREE; +} + +/* Return TRUE if CALL is a call to a builtin atomic/sync operation. */ + +static bool +is_sync_builtin_call (gcall *call) +{ + tree callee = gimple_call_fndecl (call); + + if (callee != NULL_TREE + && gimple_call_builtin_p (call, BUILT_IN_NORMAL)) + switch (DECL_FUNCTION_CODE (callee)) + { +#undef DEF_SYNC_BUILTIN +#define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM: +#include "sync-builtins.def" +#undef DEF_SYNC_BUILTIN + return true; + + default: + ; + } + + return false; +} + /* Main entry point for oacc transformations which run on the device compiler after LTO, so we know what the target device is at this point (including the host fallback). */ @@ -1815,6 +1888,66 @@ execute_oacc_device_lower () gsi_next (&gsi); } + /* Make adjustments to gang-private local variables if required by the + target, e.g. forcing them into a particular address space. Afterwards, + ADDR_EXPR nodes which have adjusted variables as their argument need to + be modified in one of two ways: + + 1. They can be recreated, making a pointer to the variable in the new + address space, or + + 2. The address of the variable in the new address space can be taken, + converted to the default (original) address space, and the result of + that conversion subsituted in place of the original ADDR_EXPR node. + + Which of these is done depends on the gimple statement being processed. + At present atomic operations and inline asms use (1), and everything else + uses (2). At least on AMD GCN, there are atomic operations that work + directly in the LDS address space. */ + + if (targetm.goacc.adjust_gangprivate_decl) + { + tree var; + unsigned i; + hash_set<tree> adjusted_vars; + + FOR_EACH_LOCAL_DECL (cfun, i, var) + { + if (!VAR_P (var) + || !lookup_attribute ("oacc gangprivate", DECL_ATTRIBUTES (var))) + continue; + + targetm.goacc.adjust_gangprivate_decl (var); + adjusted_vars.add (var); + } + + FOR_ALL_BB_FN (bb, cfun) + for (gimple_stmt_iterator gsi = gsi_start_bb (bb); + !gsi_end_p (gsi); + gsi_next (&gsi)) + { + gimple *stmt = gsi_stmt (gsi); + walk_stmt_info wi; + addr_expr_rewrite_info info; + + info.avoid_pointer_conversion + = (is_gimple_call (stmt) + && is_sync_builtin_call (as_a <gcall *> (stmt))) + || gimple_code (stmt) == GIMPLE_ASM; + info.stmt = stmt; + info.modified = false; + info.adjusted_vars = &adjusted_vars; + + memset (&wi, 0, sizeof (wi)); + wi.info = &info; + + walk_gimple_op (stmt, rewrite_addr_expr, &wi); + + if (info.modified) + update_stmt (stmt); + } + } + free_oacc_loop (loops); return 0; diff --git a/gcc/target.def b/gcc/target.def index d26b888a485..d82db232e40 100644 --- a/gcc/target.def +++ b/gcc/target.def @@ -1729,6 +1729,12 @@ handle this VAR_DECL, and normal RTL expanding is resumed.", rtx, (tree var), NULL) +DEFHOOK +(adjust_gangprivate_decl, +"Tweak variable declaration for a gang-private variable.", +void, (tree var), +NULL) + DEFHOOK (explode_args, "Define this hook to TRUE if arguments to offload regions should be\n\ -- 2.22.0
