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Implement omp atomic load and store. 

* gimple-pretty-print.c (dump_gimple_omp_atomic_load): Dump needed.
	(dump_gimple_omp_atomic_store): Likewise.
	* optabs.c (can_atomic_exchange_p): New.
	* optabs.h (can_atomic_exchange_p): Declare.
	* omp-low.c (expand_omp_atomic_load): Implement.
	(expand_omp_atomic_store): Likewise.
	(expand_omp_atomic): Update for new arguments to load/store.

From-SVN: r181296
This commit is contained in:
Richard Henderson 2011-11-11 09:52:11 -08:00 committed by Richard Henderson
parent f05eec4a0d
commit 0540978881
5 changed files with 160 additions and 25 deletions
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10
gcc/ChangeLog
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@ -1,3 +1,13 @@
2011-11-11 Richard Henderson <rth@redhat.com>
* gimple-pretty-print.c (dump_gimple_omp_atomic_load): Dump needed.
(dump_gimple_omp_atomic_store): Likewise.
* optabs.c (can_atomic_exchange_p): New.
* optabs.h (can_atomic_exchange_p): Declare.
* omp-low.c (expand_omp_atomic_load): Implement.
(expand_omp_atomic_store): Likewise.
(expand_omp_atomic): Update for new arguments to load/store.
2011-11-11 Eric Botcazou <ebotcazou@adacore.com>
* cprop.c: Adjust outdated comments throughout.

7
gcc/gimple-pretty-print.c
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@ -1768,6 +1768,8 @@ dump_gimple_omp_atomic_load (pretty_printer *buffer, gimple gs, int spc,
else
{
pp_string (buffer, "#pragma omp atomic_load");
if (gimple_omp_atomic_need_value_p (gs))
pp_string (buffer, " [needed]");
newline_and_indent (buffer, spc + 2);
dump_generic_node (buffer, gimple_omp_atomic_load_lhs (gs),
spc, flags, false);
@ -1795,7 +1797,10 @@ dump_gimple_omp_atomic_store (pretty_printer *buffer, gimple gs, int spc,
}
else
{
pp_string (buffer, "#pragma omp atomic_store (");
pp_string (buffer, "#pragma omp atomic_store ");
if (gimple_omp_atomic_need_value_p (gs))
pp_string (buffer, "[needed] ");
pp_character (buffer, '(');
dump_generic_node (buffer, gimple_omp_atomic_store_val (gs),
spc, flags, false);
pp_character (buffer, ')');

145
gcc/omp-low.c
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@ -4977,25 +4977,125 @@ expand_omp_synch (struct omp_region *region)
operation as a normal volatile load. */
static bool
expand_omp_atomic_load (basic_block load_bb, tree addr, tree loaded_val)
expand_omp_atomic_load (basic_block load_bb, tree addr,
tree loaded_val, int index)
{
/* FIXME */
(void) load_bb;
(void) addr;
(void) loaded_val;
return false;
enum built_in_function tmpbase;
gimple_stmt_iterator gsi;
basic_block store_bb;
location_t loc;
gimple stmt;
tree decl, call, type, itype;
gsi = gsi_last_bb (load_bb);
stmt = gsi_stmt (gsi);
gcc_assert (gimple_code (stmt) == GIMPLE_OMP_ATOMIC_LOAD);
loc = gimple_location (stmt);
/* ??? If the target does not implement atomic_load_optab[mode], and mode
is smaller than word size, then expand_atomic_load assumes that the load
is atomic. We could avoid the builtin entirely in this case. */
tmpbase = (enum built_in_function) (BUILT_IN_ATOMIC_LOAD_N + index + 1);
decl = builtin_decl_explicit (tmpbase);
if (decl == NULL_TREE)
return false;
type = TREE_TYPE (loaded_val);
itype = TREE_TYPE (TREE_TYPE (decl));
call = build_call_expr_loc (loc, decl, 2, addr,
build_int_cst (NULL, MEMMODEL_RELAXED));
if (!useless_type_conversion_p (type, itype))
call = fold_build1_loc (loc, VIEW_CONVERT_EXPR, type, call);
call = build2_loc (loc, MODIFY_EXPR, void_type_node, loaded_val, call);
force_gimple_operand_gsi (&gsi, call, true, NULL_TREE, true, GSI_SAME_STMT);
gsi_remove (&gsi, true);
store_bb = single_succ (load_bb);
gsi = gsi_last_bb (store_bb);
gcc_assert (gimple_code (gsi_stmt (gsi)) == GIMPLE_OMP_ATOMIC_STORE);
gsi_remove (&gsi, true);
if (gimple_in_ssa_p (cfun))
update_ssa (TODO_update_ssa_no_phi);
return true;
}
/* A subroutine of expand_omp_atomic. Attempt to implement the atomic
operation as a normal volatile store. */
static bool
expand_omp_atomic_store (basic_block load_bb, tree addr)
expand_omp_atomic_store (basic_block load_bb, tree addr,
tree loaded_val, tree stored_val, int index)
{
/* FIXME */
(void) load_bb;
(void) addr;
return false;
enum built_in_function tmpbase;
gimple_stmt_iterator gsi;
basic_block store_bb = single_succ (load_bb);
location_t loc;
gimple stmt;
tree decl, call, type, itype;
enum machine_mode imode;
bool exchange;
gsi = gsi_last_bb (load_bb);
stmt = gsi_stmt (gsi);
gcc_assert (gimple_code (stmt) == GIMPLE_OMP_ATOMIC_LOAD);
/* If the load value is needed, then this isn't a store but an exchange. */
exchange = gimple_omp_atomic_need_value_p (stmt);
gsi = gsi_last_bb (store_bb);
stmt = gsi_stmt (gsi);
gcc_assert (gimple_code (stmt) == GIMPLE_OMP_ATOMIC_STORE);
loc = gimple_location (stmt);
/* ??? If the target does not implement atomic_store_optab[mode], and mode
is smaller than word size, then expand_atomic_store assumes that the store
is atomic. We could avoid the builtin entirely in this case. */
tmpbase = (exchange ? BUILT_IN_ATOMIC_EXCHANGE_N : BUILT_IN_ATOMIC_STORE_N);
tmpbase = (enum built_in_function) ((int) tmpbase + index + 1);
decl = builtin_decl_explicit (tmpbase);
if (decl == NULL_TREE)
return false;
type = TREE_TYPE (stored_val);
/* Dig out the type of the function's second argument. */
itype = TREE_TYPE (decl);
itype = TYPE_ARG_TYPES (itype);
itype = TREE_CHAIN (itype);
itype = TREE_VALUE (itype);
imode = TYPE_MODE (itype);
if (exchange && !can_atomic_exchange_p (imode, true))
return false;
if (!useless_type_conversion_p (itype, type))
stored_val = fold_build1_loc (loc, VIEW_CONVERT_EXPR, itype, stored_val);
call = build_call_expr_loc (loc, decl, 3, addr, stored_val,
build_int_cst (NULL, MEMMODEL_RELAXED));
if (exchange)
{
if (!useless_type_conversion_p (type, itype))
call = build1_loc (loc, VIEW_CONVERT_EXPR, type, call);
call = build2_loc (loc, MODIFY_EXPR, void_type_node, loaded_val, call);
}
force_gimple_operand_gsi (&gsi, call, true, NULL_TREE, true, GSI_SAME_STMT);
gsi_remove (&gsi, true);
/* Remove the GIMPLE_OMP_ATOMIC_LOAD that we verified above. */
gsi = gsi_last_bb (load_bb);
gsi_remove (&gsi, true);
if (gimple_in_ssa_p (cfun))
update_ssa (TODO_update_ssa_no_phi);
return true;
}
/* A subroutine of expand_omp_atomic. Attempt to implement the atomic
@ -5335,7 +5435,7 @@ expand_omp_atomic_pipeline (basic_block load_bb, basic_block store_bb,
loaded_val = *addr;
and replace
GIMPLE_OMP_ATOMIC_ATORE (stored_val) with
GIMPLE_OMP_ATOMIC_STORE (stored_val) with
*addr = stored_val;
*/
@ -5403,33 +5503,30 @@ expand_omp_atomic (struct omp_region *region)
/* __sync builtins require strict data alignment. */
if (exact_log2 (align) >= index)
{
/* Atomic load. FIXME: have some target hook signalize what loads
are actually atomic? */
/* Atomic load. */
if (loaded_val == stored_val
&& (GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT
|| GET_MODE_CLASS (TYPE_MODE (type)) == MODE_FLOAT)
&& GET_MODE_BITSIZE (TYPE_MODE (type)) <= BITS_PER_WORD
&& expand_omp_atomic_load (load_bb, addr, loaded_val))
&& expand_omp_atomic_load (load_bb, addr, loaded_val, index))
return;
/* Atomic store. FIXME: have some target hook signalize what
stores are actually atomic? */
/* Atomic store. */
if ((GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT
|| GET_MODE_CLASS (TYPE_MODE (type)) == MODE_FLOAT)
&& GET_MODE_BITSIZE (TYPE_MODE (type)) <= BITS_PER_WORD
&& store_bb == single_succ (load_bb)
&& first_stmt (store_bb) == store
&& expand_omp_atomic_store (load_bb, addr))
&& expand_omp_atomic_store (load_bb, addr, loaded_val,
stored_val, index))
return;
/* When possible, use specialized atomic update functions. */
if ((INTEGRAL_TYPE_P (type) || POINTER_TYPE_P (type))
&& store_bb == single_succ (load_bb))
{
if (expand_omp_atomic_fetch_op (load_bb, addr,
loaded_val, stored_val, index))
return;
}
&& store_bb == single_succ (load_bb)
&& expand_omp_atomic_fetch_op (load_bb, addr,
loaded_val, stored_val, index))
return;
/* If we don't have specialized __sync builtins, try and implement
as a compare and swap loop. */

20
gcc/optabs.c
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@ -7236,6 +7236,26 @@ can_compare_and_swap_p (enum machine_mode mode, bool allow_libcall)
return false;
}
/* Return true if an atomic exchange can be performed. */
bool
can_atomic_exchange_p (enum machine_mode mode, bool allow_libcall)
{
enum insn_code icode;
/* Check for __atomic_exchange. */
icode = direct_optab_handler (atomic_exchange_optab, mode);
if (icode != CODE_FOR_nothing)
return true;
/* Don't check __sync_test_and_set, as on some platforms that
has reduced functionality. Targets that really do support
a proper exchange should simply be updated to the __atomics. */
return can_compare_and_swap_p (mode, allow_libcall);
}
/* Helper function to find the MODE_CC set in a sync_compare_and_swap
pattern. */

3
gcc/optabs.h
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@ -971,6 +971,9 @@ enum insn_code can_float_p (enum machine_mode, enum machine_mode, int);
/* Return true if there is an inline compare and swap pattern. */
extern bool can_compare_and_swap_p (enum machine_mode, bool);
/* Return true if there is an inline atomic exchange pattern. */
extern bool can_atomic_exchange_p (enum machine_mode, bool);
/* Generate code for a compare and swap. */
extern bool expand_atomic_compare_and_swap (rtx *, rtx *, rtx, rtx, rtx, bool,
enum memmodel, enum memmodel);