Hello,
On 07 Oct 11:09, Jeff Law wrote:
> On 10/05/2015 07:24 AM, Joseph Myers wrote:
> >On Mon, 5 Oct 2015, Kirill Yukhin wrote:
> >
> >>To enable vectorization of loops w/ calls to math functions it is reasonable
> >>to enable parsing of attribute vector for functions unconditionally and
> >>change GlibC's header file not to use `omp declare simd', but use
> >>__attribute__((vector)) instead.
> >
> >I assume you mean __vector__, for namespace reasons. Obviously you need
> >appropriate GCC version conditionals in the headers to use the attribute
> >only when supported. In addition, (a) this attribute doesn't seem to be
> >documented in extend.texi, and you'll need to include documentation in
> >your GCC patch that makes this a generic extension rather than just part
> >of Cilkplus, and (b) you'll need to agree with the x86_64 ABI mailing list
> >an extension of the ABI document (as attached to
> ><https://sourceware.org/glibc/wiki/libmvec>) to cover this attribute, and
> >update the document there.
> I'm not sure why this attribute isn't documented, but clearly that should be
> fixed.
>
> From the GCC side, I don't see a compelling reason to keep this attribute
> conditional on Cilk+ support. One could very easily want to use the math
> library's vector entry points independent of OpenMP or Cilk+.
>
> I thought the ABI for this stuff was consistent across the implementations
> (that was certainly the goal). So aside from an example of how to use the
> attribute to get calls into the vector math library, I'm not sure what's
> needed. Essentially the attribute is just another way to ensure we exploit
> the vector library when possible.
>
> It also seems to me that showing that example on the libmvec page would be
> advisable.
Patch in the bottom introduces new attribute called `simd'.
I've decided to introduce a new one since Cilk's `vector' attribute
generates only one version of SIMD-enabled function [1] (which one -
implementation specific).
This new attribute shouldn't be used along w/ Cilk's `vector'.
If it is used w/ `pragma omp declare simd' - it is ignored.
Bootstrapped. New tests pass.
gcc/
* c/c-parser.c (c_parser): Add simd_attr_present flag.
(c_parser_declaration_or_fndef): Call c_parser_declaration_or_fndef
if simd_attr_present is set.
(c_finish_omp_declare_simd): Handle simd_attr_present.
* omp-low.c (pass_omp_simd_clone::gate): If target allows - call
without additional conditions.
gcc/testsuite/
* c-c++-common/attr-simd.c: New test.
* c-c++-common/attr-simd-2.c: Ditto.
* c-c++-common/attr-simd-3.c: Ditto.
Is it ok for trunk?
Here is a description for new attribute:
simd
Enables creation of one or more versions that can process multiple
arguments using
SIMD instructions from a single invocation from a SIMD loop. It is
ultimately an alias
to `omp declare simd’ pragma, available w/o additional compiler
switches.
It is prohibited to use the attribute along with Cilk Plus’s `vector’
attribute.
If the attribute is specified and `pragma omp declare simd’ presents on
a decl, then
the attribute is ignored.
[1] -
https://www.cilkplus.org/sites/default/files/open_specifications/Intel_Cilk_plus_lang_spec_1.2.htm#elem.attr
--
Thanks, K
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 2d24c21..b83c9d8 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -224,6 +224,9 @@ struct GTY(()) c_parser {
/* Buffer to hold all the tokens from parsing the vector attribute for the
SIMD-enabled functions (formerly known as elemental functions). */
vec <c_token, va_gc> *cilk_simd_fn_tokens;
+
+ /* Designates if "simd" attribute is specified in decl. */
+ BOOL_BITFIELD simd_attr_present : 1;
};
@@ -1700,7 +1703,8 @@ c_parser_declaration_or_fndef (c_parser *parser, bool
fndef_ok,
if (declarator == NULL)
{
if (omp_declare_simd_clauses.exists ()
- || !vec_safe_is_empty (parser->cilk_simd_fn_tokens))
+ || !vec_safe_is_empty (parser->cilk_simd_fn_tokens)
+ || parser->simd_attr_present)
c_finish_omp_declare_simd (parser, NULL_TREE, NULL_TREE,
omp_declare_simd_clauses);
c_parser_skip_to_end_of_block_or_statement (parser);
@@ -1796,7 +1800,8 @@ c_parser_declaration_or_fndef (c_parser *parser, bool
fndef_ok,
if (!d)
d = error_mark_node;
if (omp_declare_simd_clauses.exists ()
- || !vec_safe_is_empty (parser->cilk_simd_fn_tokens))
+ || !vec_safe_is_empty (parser->cilk_simd_fn_tokens)
+ || parser->simd_attr_present)
c_finish_omp_declare_simd (parser, d, NULL_TREE,
omp_declare_simd_clauses);
}
@@ -1809,7 +1814,8 @@ c_parser_declaration_or_fndef (c_parser *parser, bool
fndef_ok,
if (!d)
d = error_mark_node;
if (omp_declare_simd_clauses.exists ()
- || !vec_safe_is_empty (parser->cilk_simd_fn_tokens))
+ || !vec_safe_is_empty (parser->cilk_simd_fn_tokens)
+ || parser->simd_attr_present)
c_finish_omp_declare_simd (parser, d, NULL_TREE,
omp_declare_simd_clauses);
start_init (d, asm_name, global_bindings_p ());
@@ -1838,7 +1844,8 @@ c_parser_declaration_or_fndef (c_parser *parser, bool
fndef_ok,
chainon (postfix_attrs,
all_prefix_attrs));
if (omp_declare_simd_clauses.exists ()
- || !vec_safe_is_empty (parser->cilk_simd_fn_tokens))
+ || !vec_safe_is_empty (parser->cilk_simd_fn_tokens)
+ || parser->simd_attr_present)
{
tree parms = NULL_TREE;
if (d && TREE_CODE (d) == FUNCTION_DECL)
@@ -1967,7 +1974,8 @@ c_parser_declaration_or_fndef (c_parser *parser, bool
fndef_ok,
true, false, NULL, vNULL);
store_parm_decls ();
if (omp_declare_simd_clauses.exists ()
- || !vec_safe_is_empty (parser->cilk_simd_fn_tokens))
+ || !vec_safe_is_empty (parser->cilk_simd_fn_tokens)
+ || parser->simd_attr_present)
c_finish_omp_declare_simd (parser, current_function_decl, NULL_TREE,
omp_declare_simd_clauses);
DECL_STRUCT_FUNCTION (current_function_decl)->function_start_locus
@@ -3998,6 +4006,12 @@ c_parser_attributes (c_parser *parser)
c_parser_cilk_simd_fn_vector_attrs (parser, *v_token);
continue;
}
+ if (is_attribute_p ("simd", attr_name))
+ {
+ parser->simd_attr_present = 1;
+ c_parser_consume_token (parser);
+ continue;
+ }
c_parser_consume_token (parser);
if (c_parser_next_token_is_not (parser, CPP_OPEN_PAREN))
{
@@ -14210,9 +14224,10 @@ c_finish_omp_declare_simd (c_parser *parser, tree
fndecl, tree parms,
vec<c_token> clauses)
{
if (flag_cilkplus
- && clauses.exists () && !vec_safe_is_empty (parser->cilk_simd_fn_tokens))
+ && (clauses.exists () || parser->simd_attr_present)
+ && !vec_safe_is_empty (parser->cilk_simd_fn_tokens))
{
- error ("%<#pragma omp declare simd%> cannot be used in the same "
+ error ("%<#pragma omp declare simd%> or __simd__ attribute cannot be
used in the same "
"function marked as a Cilk Plus SIMD-enabled function");
vec_free (parser->cilk_simd_fn_tokens);
return;
@@ -14257,41 +14272,63 @@ c_finish_omp_declare_simd (c_parser *parser, tree
fndecl, tree parms,
parser->tokens = clauses.address ();
parser->tokens_avail = clauses.length ();
}
-
- /* c_parser_omp_declare_simd pushed 2 extra CPP_EOF tokens at the end. */
- while (parser->tokens_avail > 3)
+
+ if (parser->simd_attr_present
+ && is_cilkplus_cilk_simd_fn)
{
- c_token *token = c_parser_peek_token (parser);
- if (!is_cilkplus_cilk_simd_fn)
- gcc_assert (token->type == CPP_NAME
- && strcmp (IDENTIFIER_POINTER (token->value), "simd") == 0);
- else
- gcc_assert (token->type == CPP_NAME
- && is_cilkplus_vector_p (token->value));
- c_parser_consume_token (parser);
- parser->in_pragma = true;
+ error ("SIMD-enabled function attributes"
+ "are allowed when attribute __simd__ is specified");
+ clauses[0].type = CPP_EOF;
+ return;
+ }
+ /* Attach `omp declare simd’ attribute if __simd__ is specified AND no
OpenMP clauses
+ present in decl. */
+ if (parser->simd_attr_present
+ && parser->tokens_avail == 0)
+ {
tree c = NULL_TREE;
- if (is_cilkplus_cilk_simd_fn)
- c = c_parser_omp_all_clauses (parser, CILK_SIMD_FN_CLAUSE_MASK,
- "SIMD-enabled functions attribute");
- else
- c = c_parser_omp_all_clauses (parser, OMP_DECLARE_SIMD_CLAUSE_MASK,
- "#pragma omp declare simd");
- c = c_omp_declare_simd_clauses_to_numbers (parms, c);
- if (c != NULL_TREE)
- c = tree_cons (NULL_TREE, c, NULL_TREE);
- if (is_cilkplus_cilk_simd_fn)
- {
- tree k = build_tree_list (get_identifier ("cilk simd function"),
- NULL_TREE);
- TREE_CHAIN (k) = DECL_ATTRIBUTES (fndecl);
- DECL_ATTRIBUTES (fndecl) = k;
- }
c = build_tree_list (get_identifier ("omp declare simd"), c);
TREE_CHAIN (c) = DECL_ATTRIBUTES (fndecl);
DECL_ATTRIBUTES (fndecl) = c;
}
+ else
+ {
+ /* c_parser_omp_declare_simd pushed 2 extra CPP_EOF tokens at the end.
*/
+ while (parser->tokens_avail > 3)
+ {
+ c_token *token = c_parser_peek_token (parser);
+ if (!is_cilkplus_cilk_simd_fn)
+ gcc_assert (token->type == CPP_NAME
+ && strcmp (IDENTIFIER_POINTER (token->value), "simd")
== 0);
+ else
+ gcc_assert (token->type == CPP_NAME
+ && is_cilkplus_vector_p (token->value));
+ c_parser_consume_token (parser);
+ parser->in_pragma = true;
+
+ tree c = NULL_TREE;
+ if (is_cilkplus_cilk_simd_fn)
+ c = c_parser_omp_all_clauses (parser, CILK_SIMD_FN_CLAUSE_MASK,
+ "SIMD-enabled functions attribute");
+ else
+ c = c_parser_omp_all_clauses (parser, OMP_DECLARE_SIMD_CLAUSE_MASK,
+ "#pragma omp declare simd");
+ c = c_omp_declare_simd_clauses_to_numbers (parms, c);
+ if (c != NULL_TREE)
+ c = tree_cons (NULL_TREE, c, NULL_TREE);
+ if (is_cilkplus_cilk_simd_fn)
+ {
+ tree k = build_tree_list (get_identifier ("cilk simd function"),
+ NULL_TREE);
+ TREE_CHAIN (k) = DECL_ATTRIBUTES (fndecl);
+ DECL_ATTRIBUTES (fndecl) = k;
+ }
+ c = build_tree_list (get_identifier ("omp declare simd"), c);
+ TREE_CHAIN (c) = DECL_ATTRIBUTES (fndecl);
+ DECL_ATTRIBUTES (fndecl) = c;
+ }
+ }
parser->tokens = &parser->tokens_buf[0];
parser->tokens_avail = tokens_avail;
diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index cdcf9d6..87537cd 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -13919,10 +13919,7 @@ public:
bool
pass_omp_simd_clone::gate (function *)
{
- return ((flag_openmp || flag_openmp_simd
- || flag_cilkplus
- || (in_lto_p && !flag_wpa))
- && (targetm.simd_clone.compute_vecsize_and_simdlen != NULL));
+ return targetm.simd_clone.compute_vecsize_and_simdlen != NULL;
}
} // anon namespace
diff --git a/gcc/testsuite/c-c++-common/attr-simd-2.c
b/gcc/testsuite/c-c++-common/attr-simd-2.c
new file mode 100644
index 0000000..263fa9a
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/attr-simd-2.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-optimized -fopenmp-simd" } */
+
+#pragma omp declare simd
+__attribute__((__simd__))
+static int simd_attr (void)
+{
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump "simdclone" "optimized" } } */
diff --git a/gcc/testsuite/c-c++-common/attr-simd-3.c
b/gcc/testsuite/c-c++-common/attr-simd-3.c
new file mode 100644
index 0000000..2bbdf04
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/attr-simd-3.c
@@ -0,0 +1,5 @@
+/* { dg-do compile } */
+/* { dg-options "-fcilkplus" } */
+/* { dg-prune-output "undeclared here \\(not in a function\\)|\[^\n\r\]* was
not declared in this scope" } */
+
+void f () __attribute__((__simd__, __vector__)); /* { dg-error "in the same
function marked as a Cilk Plus" } */
diff --git a/gcc/testsuite/c-c++-common/attr-simd.c
b/gcc/testsuite/c-c++-common/attr-simd.c
new file mode 100644
index 0000000..5dad89c
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/attr-simd.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-optimized" } */
+
+__attribute__((__simd__))
+static int simd_attr (void)
+{
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump "simdclone" "optimized" } } */
