openmp: Avoid calling clear_type_padding_in_mask in the common case where there can...

We can use the clear_padding_type_may_have_padding_p function, which
is conservative for e.g. RECORD_TYPE/UNION_TYPE, but for the floating and
complex floating types is accurate.  clear_type_padding_in_mask is
more expensive because we need to allocate memory, fill it, call the function
which itself is more expensive and then analyze the memory, so for the
common case of float/double atomics or even long double on most targets
we can avoid that.

2021-10-12  Jakub Jelinek  <jakub@redhat.com>

gcc/
	* gimple-fold.h (clear_padding_type_may_have_padding_p): Declare.
	* gimple-fold.c (clear_padding_type_may_have_padding_p): No longer
	static.
gcc/c-family/
	* c-omp.c (c_finish_omp_atomic): Use
	clear_padding_type_may_have_padding_p.

diff --git a/gcc/c-family/c-omp.c b/gcc/c-family/c-omp.c
index d8b98552fb9e31daa365589b0591ec2d6684d70b..b9024cb15a9123533dbd29c15a26774076e17a6a 100644 (file)
--- a/gcc/c-family/c-omp.c
+++ b/gcc/c-family/c-omp.c
@@ -381,7 +381,9 @@ c_finish_omp_atomic (location_t loc, enum tree_code code,
          bool clear_padding = false;
          HOST_WIDE_INT non_padding_start = 0;
          HOST_WIDE_INT non_padding_end = 0;
-         if (BITS_PER_UNIT == 8 && CHAR_BIT == 8)
+         if (BITS_PER_UNIT == 8
+             && CHAR_BIT == 8
+             && clear_padding_type_may_have_padding_p (cmptype))
            {
              HOST_WIDE_INT sz = int_size_in_bytes (cmptype), i;
              gcc_assert (sz > 0);

diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 474d0f44375522cab9767a2570d08979d4e0231b..7fcfef41f7229f92830201c350cf82b861cbbcac 100644 (file)
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -4632,7 +4632,7 @@ clear_padding_real_needs_padding_p (tree type)
 
 /* Return true if TYPE might contain any padding bits.  */
 
-static bool
+bool
 clear_padding_type_may_have_padding_p (tree type)
 {
   switch (TREE_CODE (type))

diff --git a/gcc/gimple-fold.h b/gcc/gimple-fold.h
index 2401646c48454d1f51a85c48973a278063e5949d..397f4aeb7cfe5c87176ec9f3dd32fea611595e81 100644 (file)
--- a/gcc/gimple-fold.h
+++ b/gcc/gimple-fold.h
@@ -36,6 +36,7 @@ extern tree maybe_fold_and_comparisons (tree, enum tree_code, tree, tree,
                                        enum tree_code, tree, tree);
 extern tree maybe_fold_or_comparisons (tree, enum tree_code, tree, tree,
                                       enum tree_code, tree, tree);
+extern bool clear_padding_type_may_have_padding_p (tree);
 extern void clear_type_padding_in_mask (tree, unsigned char *);
 extern bool optimize_atomic_compare_exchange_p (gimple *);
 extern void fold_builtin_atomic_compare_exchange (gimple_stmt_iterator *);