openmp: Improve expand_omp_atomic_pipeline

When __atomic_* builtins were introduced, omp-expand.c (omp-low.c
at that point) has been adjusted in several spots so that it uses
the atomic builtins instead of sync builtins, but
expand_omp_atomic_pipeline has not because the __atomic_compare_exchange_*
APIs take address of the argument, so it kept using __sync_val_compare_swap_*.
That means it always uses seq_cst though.
This patch changes it to use the ATOMIC_COMPARE_EXCHANGE ifn which gimple-fold
folds __atomic_compare_exchange_* into - that ifn also passes expected
directly.

2021-09-03  Jakub Jelinek  <jakub@redhat.com>

	* omp-expand.c (expand_omp_atomic_pipeline): Use
	IFN_ATOMIC_COMPARE_EXCHANGE instead of
	BUILT_IN_SYNC_VAL_COMPARE_AND_SWAP_? so that memory order
	can be provided.

(cherry picked from commit 090f0d78f194e3cda23fe904016db77ea36c38fa)

diff --git a/gcc/ChangeLog.omp b/gcc/ChangeLog.omp
index 59678d62af4464fe89bc09d52bb6e946eeae8002..b4231380da4f098170b5b29a57229e333b425b64 100644 (file)
--- a/gcc/ChangeLog.omp
+++ b/gcc/ChangeLog.omp
@@ -1,49 +1,57 @@
+2021-09-03  Tobias Burnus  <tobias@codesourcery.com>
+
+       2021-09-03  Jakub Jelinek  <jakub@redhat.com>
+
+       * omp-expand.c (expand_omp_atomic_pipeline): Use
+       IFN_ATOMIC_COMPARE_EXCHANGE instead of
+       BUILT_IN_SYNC_VAL_COMPARE_AND_SWAP_? so that memory order
+       can be provided.
+
 2021-09-02  Marcel Vollweiler  <marcel@codesourcery.com>
 
        Backported from master:
        2021-09-02  Marcel Vollweiler  <marcel@codesourcery.com>
 
-        * gfortran.dg/gomp/target-device-ancestor-4.f90: Comment out dg-final to avoid
-        UNRESOLVED.
+       * gfortran.dg/gomp/target-device-ancestor-4.f90: Comment out dg-final to avoid
+       UNRESOLVED.
 
 2021-08-31  Marcel Vollweiler  <marcel@codesourcery.com>
 
        Backported from master:
        2021-08-31  Marcel Vollweiler  <marcel@codesourcery.com>
 
-        * c-parser.c (c_parser_omp_clause_device): Parse device-modifiers 'device_num'
-        and 'ancestor' in 'target device' clauses.
-        * parser.c (cp_parser_omp_clause_device): Parse device-modifiers 'device_num'
-        and 'ancestor' in 'target device' clauses.
-        * semantics.c (finish_omp_clauses): Error handling. Constant device ids must
-        evaluate to '1' if 'ancestor' is used.
-        * gfortran.h: Add variable for 'ancestor' in struct gfc_omp_clauses.
-        * openmp.c (gfc_match_omp_clauses): Parse device-modifiers 'device_num'
-        and 'ancestor' in 'target device' clauses.
-        * trans-openmp.c (gfc_trans_omp_clauses): Set OMP_CLAUSE_DEVICE_ANCESTOR.
-        * gimplify.c (gimplify_scan_omp_clauses): Error handling. 'ancestor' only
-        allowed on target constructs and only with particular other clauses.
-        * omp-expand.c (expand_omp_target): Output of 'sorry, not supported' if
-        'ancestor' is used.
-        * omp-low.c (check_omp_nesting_restrictions): Error handling. No nested OpenMP
-        structs when 'ancestor' is used.
-        (scan_omp_1_stmt): No usage of OpenMP runtime routines in a target region when
-        'ancestor' is used.
-        * tree-pretty-print.c (dump_omp_clause): Append 'ancestor'.
-        * tree.h (OMP_CLAUSE_DEVICE_ANCESTOR): Define macro.
-        * c-c++-common/gomp/target-device-1.c: New test.
-        * c-c++-common/gomp/target-device-2.c: New test.
-        * c-c++-common/gomp/target-device-ancestor-1.c: New test.
-        * c-c++-common/gomp/target-device-ancestor-2.c: New test.
-        * c-c++-common/gomp/target-device-ancestor-3.c: New test.
-        * c-c++-common/gomp/target-device-ancestor-4.c: New test.
-        * gfortran.dg/gomp/target-device-1.f90: New test.
-        * gfortran.dg/gomp/target-device-2.f90: New test.
-        * gfortran.dg/gomp/target-device-ancestor-1.f90: New test.
-        * gfortran.dg/gomp/target-device-ancestor-2.f90: New test.
-        * gfortran.dg/gomp/target-device-ancestor-3.f90: New test.
-        * gfortran.dg/gomp/target-device-ancestor-4.f90: New test.
-
+       * c-parser.c (c_parser_omp_clause_device): Parse device-modifiers 'device_num'
+       and 'ancestor' in 'target device' clauses.
+       * parser.c (cp_parser_omp_clause_device): Parse device-modifiers 'device_num'
+       and 'ancestor' in 'target device' clauses.
+       * semantics.c (finish_omp_clauses): Error handling. Constant device ids must
+       evaluate to '1' if 'ancestor' is used.
+       * gfortran.h: Add variable for 'ancestor' in struct gfc_omp_clauses.
+       * openmp.c (gfc_match_omp_clauses): Parse device-modifiers 'device_num'
+       and 'ancestor' in 'target device' clauses.
+       * trans-openmp.c (gfc_trans_omp_clauses): Set OMP_CLAUSE_DEVICE_ANCESTOR.
+       * gimplify.c (gimplify_scan_omp_clauses): Error handling. 'ancestor' only
+       allowed on target constructs and only with particular other clauses.
+       * omp-expand.c (expand_omp_target): Output of 'sorry, not supported' if
+       'ancestor' is used.
+       * omp-low.c (check_omp_nesting_restrictions): Error handling. No nested OpenMP
+       structs when 'ancestor' is used.
+       (scan_omp_1_stmt): No usage of OpenMP runtime routines in a target region when
+       'ancestor' is used.
+       * tree-pretty-print.c (dump_omp_clause): Append 'ancestor'.
+       * tree.h (OMP_CLAUSE_DEVICE_ANCESTOR): Define macro.
+       * c-c++-common/gomp/target-device-1.c: New test.
+       * c-c++-common/gomp/target-device-2.c: New test.
+       * c-c++-common/gomp/target-device-ancestor-1.c: New test.
+       * c-c++-common/gomp/target-device-ancestor-2.c: New test.
+       * c-c++-common/gomp/target-device-ancestor-3.c: New test.
+       * c-c++-common/gomp/target-device-ancestor-4.c: New test.
+       * gfortran.dg/gomp/target-device-1.f90: New test.
+       * gfortran.dg/gomp/target-device-2.f90: New test.
+       * gfortran.dg/gomp/target-device-ancestor-1.f90: New test.
+       * gfortran.dg/gomp/target-device-ancestor-2.f90: New test.
+       * gfortran.dg/gomp/target-device-ancestor-3.f90: New test.
+       * gfortran.dg/gomp/target-device-ancestor-4.f90: New test.
 
 2021-08-23  Tobias Burnus  <tobias@codesourcery.com>
 

diff --git a/gcc/omp-expand.c b/gcc/omp-expand.c
index 9cd75a91649c6cc1a2b8105e87d8b41c3e7fbfb9..6c538ebfbb127ab4f7ee9f82d9306dcce6359e66 100644 (file)
--- a/gcc/omp-expand.c
+++ b/gcc/omp-expand.c
@@ -8857,8 +8857,6 @@ expand_omp_atomic_pipeline (basic_block load_bb, basic_block store_bb,
   edge e;
   enum built_in_function fncode;
 
-  /* ??? We need a non-pointer interface to __atomic_compare_exchange in
-     order to use the RELAXED memory model effectively.  */
   fncode = (enum built_in_function)((int)BUILT_IN_SYNC_VAL_COMPARE_AND_SWAP_N
                                    + index + 1);
   cmpxchg = builtin_decl_explicit (fncode);
@@ -8875,6 +8873,15 @@ expand_omp_atomic_pipeline (basic_block load_bb, basic_block store_bb,
   /* Load the initial value, replacing the GIMPLE_OMP_ATOMIC_LOAD.  */
   si = gsi_last_nondebug_bb (load_bb);
   gcc_assert (gimple_code (gsi_stmt (si)) == GIMPLE_OMP_ATOMIC_LOAD);
+  location_t loc = gimple_location (gsi_stmt (si));
+  enum omp_memory_order omo = gimple_omp_atomic_memory_order (gsi_stmt (si));
+  enum memmodel imo = omp_memory_order_to_memmodel (omo);
+  tree mo = build_int_cst (NULL, imo);
+  if (imo == MEMMODEL_RELEASE)
+    imo = MEMMODEL_RELAXED;
+  else if (imo == MEMMODEL_ACQ_REL)
+    imo = MEMMODEL_ACQUIRE;
+  tree fmo = build_int_cst (NULL, imo);
 
   /* For floating-point values, we'll need to view-convert them to integers
      so that we can perform the atomic compare and swap.  Simplify the
@@ -8971,7 +8978,15 @@ expand_omp_atomic_pipeline (basic_block load_bb, basic_block store_bb,
                                  GSI_SAME_STMT);
 
   /* Build the compare&swap statement.  */
-  new_storedi = build_call_expr (cmpxchg, 3, iaddr, loadedi, storedi);
+  tree ctype = build_complex_type (itype);
+  int flag = int_size_in_bytes (itype);
+  new_storedi = build_call_expr_internal_loc (loc, IFN_ATOMIC_COMPARE_EXCHANGE,
+                                             ctype, 6, iaddr, loadedi,
+                                             storedi,
+                                             build_int_cst (integer_type_node,
+                                                            flag),
+                                             mo, fmo);
+  new_storedi = build1 (REALPART_EXPR, itype, new_storedi);
   new_storedi = force_gimple_operand_gsi (&si,
                                          fold_convert (TREE_TYPE (loadedi),
                                                        new_storedi),