[RFC 6/X] omp: Allow creation of simd clones from omp declare variant with -fopenmp-simd flag

["Andre Vieira (lists)" <andre.simoesdiasvieira@arm.com>]

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Hi,

This RFC is to propose relaxing the flag needed to allow the creation of 
simd clones from omp declare variants, such that we can use 
-fopenmp-simd rather than -fopenmp.
This should only change the behaviour of omp simd clones and should not 
enable any other openmp functionality, though I need to test this 
furter, for the time being I just played around a bit with some of the 
existing declare-variant tests.

Any objections to this in general? And/or ideas to properly test the 
effect of this on other omp codegen? My current plan is to have a look 
at the declare-variant tests we had before this patch series, locally 
modify them to pass -fopenmp-simd and make sure they fail the same way 
before and after this patch.

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diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 21bc3167ce224823c214efc064be399f2da9c787..b28e3d0a8adb520941dc3a17173cc07de4a653c5 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -23564,6 +23564,13 @@ c_parser_omp_declare (c_parser *parser, enum pragma_context context)
 	  c_parser_omp_declare_reduction (parser, context);
 	  return false;
 	}
+      if (strcmp (p, "variant") == 0)
+	{
+	  /* c_parser_consume_token (parser); done in
+	     c_parser_omp_declare_simd.  */
+	  c_parser_omp_declare_simd (parser, context);
+	  return true;
+	}
       if (!flag_openmp)  /* flag_openmp_simd  */
 	{
 	  c_parser_skip_to_pragma_eol (parser, false);
@@ -23575,13 +23582,6 @@ c_parser_omp_declare (c_parser *parser, enum pragma_context context)
 	  c_parser_omp_declare_target (parser);
 	  return false;
 	}
-      if (strcmp (p, "variant") == 0)
-	{
-	  /* c_parser_consume_token (parser); done in
-	     c_parser_omp_declare_simd.  */
-	  c_parser_omp_declare_simd (parser, context);
-	  return true;
-	}
     }
 
   c_parser_error (parser, "expected %<simd%>, %<reduction%>, "
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 1aa5f1a7898df9483a2af4f6f9fea99e6b219271..7bd32fd3e345a003be03d1e9acf33db76eed9460 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -8428,7 +8428,7 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
 	suppress_warning (decl, OPT_Winit_self);
     }
 
-  if (flag_openmp
+  if (flag_openmp_simd
       && TREE_CODE (decl) == FUNCTION_DECL
       /* #pragma omp declare variant on methods handled in finish_struct
 	 instead.  */
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 1a124f5395e018f3c4b2f9f36fcd42159d0b868f..d1c7f9d91d2546ad8f5674232a05f7d7726eeafe 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -47884,7 +47884,7 @@ cp_parser_omp_declare (cp_parser *parser, cp_token *pragma_tok,
 				      context, false);
 	  return true;
 	}
-      if (flag_openmp && strcmp (p, "variant") == 0)
+      if (strcmp (p, "variant") == 0)
 	{
 	  cp_lexer_consume_token (parser->lexer);
 	  cp_parser_omp_declare_simd (parser, pragma_tok,
diff --git a/gcc/testsuite/gcc.target/aarch64/declare-variant-1.c b/gcc/testsuite/gcc.target/aarch64/declare-variant-1.c
index c44c9464f4e27047db9be5b0c9710ae3cfee8eee..83eeadd108b5578623c63e73dea11b2b17a08618 100644
--- a/gcc/testsuite/gcc.target/aarch64/declare-variant-1.c
+++ b/gcc/testsuite/gcc.target/aarch64/declare-variant-1.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O3 -fopenmp" } */
+/* { dg-options "-O3 -fopenmp-simd" } */
 
 #include "declare-variant-1.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-1.c b/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-1.c
index 7a8129fe88ac9759b2337892a3d14f4e8196e61f..616b0ed1c1dc019103dae504d2cec65523a35a3d 100644
--- a/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-1.c
+++ b/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-1.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O3 -fopenmp" } */
+/* { dg-options "-O3 -fopenmp-simd" } */
 
 #include "../declare-variant-1.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-2.c b/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-2.c
index 2b6eabac76cf1cd059ec8d960ddd9e30973dc797..a832c5255306999b0006b68b1890c7f42c3dafb0 100644
--- a/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-2.c
+++ b/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-2.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O3 -fopenmp -msve-vector-bits=128" } */
+/* { dg-options "-O3 -fopenmp-simd -msve-vector-bits=128" } */
 
 #include "../declare-variant-1.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-3.c b/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-3.c
index e8b598fe479d7e1e92eb7f9e3413d5ac183626a9..455c0338d4680d143daae666c29e4f018df5bff9 100644
--- a/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-3.c
+++ b/gcc/testsuite/gcc.target/aarch64/sve/declare-variant-3.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O3 -fopenmp -msve-vector-bits=256" } */
+/* { dg-options "-O3 -fopenmp-simd -msve-vector-bits=256" } */
 
 #include "../declare-variant-1.x"