[clang] [OpenMP] Extend OpenMP variant declaration tests.

[tahonermann]

Summary

This change extends the existing diagnostic tests for OpenMP variant
declarations to cover diagnostics for declarations that include
multiversion function attributes. The new tests demonstrate a missing
check for the 'target_clones' attribute.

[tahonermann]

clang/test/OpenMP/declare_variant_messages.c

165

This FIXME comment is removed with the changes made in D121963.

[jdoerfert]

LG

[tahonermann]

Rebase.

[tahonermann]

Rebase to acquire fixes from parent commits.

clang/test/OpenMP/declare_variant_messages.c

 #pragma omp declare variant(diff_cc_variant) match(xxx={}) // expected-error {{variant in '#pragma omp declare variant' with type 'int (void)' is incompatible with type 'int (void) __attribute__((vectorcall))'}} expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
 __vectorcall int diff_cc(void);
 
 int diff_ret_variant(void);
 
 #pragma omp declare variant(diff_ret_variant) match(xxx={}) // expected-error {{variant in '#pragma omp declare variant' with type 'int (void)' is incompatible with type 'void (void)'}} expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
 void diff_ret(void);
 
+void incompat_attr_variant(void);
+
+#pragma omp declare variant(incompat_attr_variant) match(implementation={vendor(llvm)})
+__attribute__((cpu_dispatch(generic))) void incompat_attr_cpu_dispatch(void); // expected-error {{'#pragma omp declare variant' is not compatible with any target-specific attributes}}
+
+#pragma omp declare variant(incompat_attr_variant) match(implementation={vendor(llvm)})
+__attribute__((cpu_specific(generic))) void incompat_attr_cpu_specific(void); // expected-error {{'#pragma omp declare variant' is not compatible with any target-specific attributes}}
+
+// 'incompat_attr_target' is not a multiversion function until...
+#pragma omp declare variant(incompat_attr_variant) match(implementation={vendor(llvm)})
+__attribute__((target("mmx"))) void incompat_attr_target(void); // expected-error {{'#pragma omp declare variant' is not compatible with any target-specific attributes}}
+
+// This declaration makes it one.
+#pragma omp declare variant(incompat_attr_variant) match(implementation={vendor(llvm)})
+__attribute__((target("sse"))) void incompat_attr_target(void); // expected-error {{'#pragma omp declare variant' is not compatible with any target-specific attributes}}
+
+// 'incompat_attr_target_default' is always a multiversion function.
+#pragma omp declare variant(incompat_attr_variant) match(implementation={vendor(llvm)})
+__attribute__((target("default"))) void incompat_attr_target_default(void); // expected-error {{'#pragma omp declare variant' is not compatible with any target-specific attributes}}
+
+// FIXME: No diagnostics are produced for use of the 'target_clones' attribute in an OMP variant declaration.
+#pragma omp declare variant(incompat_attr_variant) match(implementation={vendor(llvm)})
+__attribute__((target_clones("sse,default"))) void incompat_attr_target_clones(void);
+
 void marked(void);
 void not_marked(void);
 
 #pragma omp declare variant(not_marked) match(implementation={vendor(unknown)}, device={kind(cpu)}) // expected-note {{marked as 'declare variant' here}}
 void marked_variant(void);
 
 #pragma omp declare variant(marked_variant) match(xxx={}) // expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-warning {{variant function in '#pragma omp declare variant' is itself marked as '#pragma omp declare variant'}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
 void marked(void);