[PATCH, VECTOR ABI] Add __attribute__((__simd__)) to GCC.

[Kirill Yukhin]

Hello Jakub,

On 13 Nov 13:16, Jakub Jelinek wrote:
> > --- /dev/null
> > +++ b/gcc/testsuite/c-c++-common/attr-simd.c
> 
> Similarly.
> 
> Ok for trunk with those changes.
It turns out that current implementation of GLibC does not
contain masked variants of math routines. So, this attribute
is useless until it is capable to generation only [nonmasked|maked]
variants of the routines.

Patch in the bottom introduces `notinbranch' and `inbranch' flags to
the attribute.

Bootstrapped and regtested. New tests pass.

Is it ok for trunk (GCC v6)?

gcc/
	* c-family/c-common.c (c_common_attribute_table[]): Update max aerguments
	count for "simd" attribute.
	(handle_simd_attribute): Parse "notinbranch" and "inbranch" arguments.
	* doc/extend.texi ("simd"): Describe new flags.
gcc/testsuite/
	* c-c++-common/attr-simd-4.c: New test.
	* c-c++-common/attr-simd-5.c: New test.

--
Thanks, K

> 
> 	Jakub

commit cf458a0a00214022556498bdda94a07d0af70574
Author: Kirill Yukhin <kirill.yukhin@intel.com>
Date:   Mon Nov 30 16:24:39 2015 +0300

    [attr-simd] Add notinbranch/inbranch flags.

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 369574f..0104306 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -818,7 +818,7 @@ const struct attribute_spec c_common_attribute_table[] =
 			      handle_omp_declare_simd_attribute, false },
   { "cilk simd function",     0, -1, true,  false, false,
 			      handle_omp_declare_simd_attribute, false },
-  { "simd",		      0, 0, true,  false, false,
+  { "simd",		      0, 1, true,  false, false,
 			      handle_simd_attribute, false },
   { "omp declare target",     0, 0, true, false, false,
 			      handle_omp_declare_target_attribute, false },
@@ -9032,7 +9032,7 @@ handle_omp_declare_simd_attribute (tree *, tree, tree, int, bool *)
 /* Handle a "simd" attribute.  */
 
 static tree
-handle_simd_attribute (tree *node, tree name, tree, int, bool *no_add_attrs)
+handle_simd_attribute (tree *node, tree name, tree args, int, bool *no_add_attrs)
 {
   if (TREE_CODE (*node) == FUNCTION_DECL)
     {
@@ -9045,9 +9045,41 @@ handle_simd_attribute (tree *node, tree name, tree, int, bool *no_add_attrs)
 	  *no_add_attrs = true;
 	}
       else
-	DECL_ATTRIBUTES (*node)
-	  = tree_cons (get_identifier ("omp declare simd"),
-		       NULL_TREE, DECL_ATTRIBUTES (*node));
+	{
+	  tree t = get_identifier ("omp declare simd");
+	  tree attr = NULL_TREE;
+	  if (args)
+	    {
+	      tree id = TREE_VALUE (args);
+
+	      if (TREE_CODE (id) != STRING_CST)
+		{
+		  error ("attribute %qE argument not a string", name);
+		  *no_add_attrs = true;
+		  return NULL_TREE;
+		}
+
+	      if (strcmp (TREE_STRING_POINTER (id), "notinbranch") == 0)
+		attr = build_omp_clause (DECL_SOURCE_LOCATION (*node),
+					 OMP_CLAUSE_NOTINBRANCH);
+	      else
+		if (strcmp (TREE_STRING_POINTER (id), "inbranch") == 0)
+		  attr = build_omp_clause (DECL_SOURCE_LOCATION (*node),
+					   OMP_CLAUSE_INBRANCH);
+		else
+		{
+		  error ("only %<inbranch%> and %<notinbranch%> flags are "
+			 "allowed for %<__simd__%> attribute");
+		  *no_add_attrs = true;
+		  return NULL_TREE;
+		}
+	    }
+
+	  DECL_ATTRIBUTES (*node) = tree_cons (t,
+					       build_tree_list (NULL_TREE,
+								attr),
+					       DECL_ATTRIBUTES (*node));
+	}
     }
   else
     {
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 63fce0f..c517038 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -3144,6 +3144,7 @@ At the function call it will create resolver @code{ifunc}, that will
 dynamically call a clone suitable for current architecture.
 
 @item simd
+@itemx simd("@var{mask}")
 @cindex @code{simd} function attribute.
 This attribute enables creation of one or more function versions that
 can process multiple arguments using SIMD instructions from a
@@ -3158,6 +3159,9 @@ attribute on the same function.
 If the attribute is specified and @code{#pragma omp declare simd}
 present on a declaration and @code{-fopenmp} or @code{-fopenmp-simd}
 switch is specified, then the attribute is ignored.
+The optional argument @var{mask} may have "notinbranch" or "inbranch"
+value and instructs the compiler to generate non-masked or masked
+clones correspondingly. By default, all clones are generated.
 
 @item target (@var{options})
 @cindex @code{target} function attribute
diff --git a/gcc/testsuite/c-c++-common/attr-simd-4.c b/gcc/testsuite/c-c++-common/attr-simd-4.c
new file mode 100644
index 0000000..66cd8f1
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/attr-simd-4.c
@@ -0,0 +1,38 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-optimized" } */
+
+extern
+#ifdef __cplusplus
+"C"
+#endif
+__attribute__((__simd__("notinbranch")))
+int simd_attr (void)
+{
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "simd_attr\[ \\t\]simdclone|vector" "optimized" { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-times "_ZGVbN4_simd_attr:" 1 { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-times "_ZGVcN4_simd_attr:" 1 { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-times "_ZGVdN8_simd_attr:" 1 { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-not "_ZGVbM4_simd_attr:" { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-not "_ZGVcM4_simd_attr:" { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-not "_ZGVdM8_simd_attr:" { target { i?86-*-* x86_64-*-* } } } } */
+
+extern
+#ifdef __cplusplus
+"C"
+#endif
+__attribute__((simd("inbranch")))
+int simd_attr2 (void)
+{
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "simd_attr2\[ \\t\]simdclone|vector" "optimized" { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-not "_ZGVbN4_simd_attr2:" { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-not "_ZGVcN4_simd_attr2:" { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-not "_ZGVdN8_simd_attr2:" { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-times "_ZGVbM4_simd_attr2:" 1 { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-times "_ZGVcM4_simd_attr2:" 1 { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-assembler-times "_ZGVdM8_simd_attr2:" 1 { target { i?86-*-* x86_64-*-* } } } } */
diff --git a/gcc/testsuite/c-c++-common/attr-simd-5.c b/gcc/testsuite/c-c++-common/attr-simd-5.c
new file mode 100644
index 0000000..7bf3f2c
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/attr-simd-5.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+
+__attribute__((__simd__("bug")))
+int simd_attr (void) { return 0; } /* { dg-error "only 'inbranch' and 'notinbranch'" } */
+
+__attribute__((__simd__("notinbranch", "inbranch")))
+int simd_attr2 (void) { return 0; } /* { dg-error "wrong number of arguments specified" } */