[openacc] C, C++ OpenACC wait diagnostic change

Attached is an old patch which updated the C and C++ FEs to use %<)%>
for the right ')' symbol. It's mostly a cosmetic change. All of the
changes are self-contained to the OpenACC code path.

Is this OK for trunk? I bootstrapped and regtested it for x86_64 Linux
with nvptx offloading.

Thanks,
Cesar

On Wed, 26 Sep 2018, Cesar Philippidis wrote:

> Attached is an old patch which updated the C and C++ FEs to use %<)%>
> for the right ')' symbol. It's mostly a cosmetic change. All of the
> changes are self-contained to the OpenACC code path.

Why is the "before ')'" included in the call to c_parser_error at all?  
c_parser_error calls c_parse_error which adds its own " before " and token 
description or expansion, so I'd expect the current error to result in a 
message ending in something of the form "before X before Y".

On 09/26/2018 12:50 PM, Joseph Myers wrote:
> On Wed, 26 Sep 2018, Cesar Philippidis wrote:
> 
>> Attached is an old patch which updated the C and C++ FEs to use %<)%>
>> for the right ')' symbol. It's mostly a cosmetic change. All of the
>> changes are self-contained to the OpenACC code path.
> 
> Why is the "before ')'" included in the call to c_parser_error at all?  
> c_parser_error calls c_parse_error which adds its own " before " and token 
> description or expansion, so I'd expect the current error to result in a 
> message ending in something of the form "before X before Y".

On closer inspection

 #pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait (1 /* {
dg-error "expected '\\\)' before end of line" } */
-    /* { dg-error "expected integer expression before '\\\)'" "" {
target c++ } .-1 } */
+    /* { dg-error "expected integer expression list before" "" { target
c++ } .-1 } */

so this is only applicable to c++. But in C++ I see duplicate errors
like this

wait.c:29:29: error: expected ‘)’ before end of line
 #pragma acc parallel wait (1
                           ~ ^
                             )
wait.c:29:29: error: expected integer expression list before ‘)’ before
end of line

I suppose for C++ that's an improvement over

wait.c:29:29: error: expected integer expression before ')' before end
of line

Julian, I need to start working on deep copy in OpenACC. Can you take
over this patch? The error handling code in the C FE needs to be removed
because it's dead.

Thanks,
Cesar

On Wed, 26 Sep 2018 14:08:37 -0700
Cesar Philippidis <cesar@codesourcery.com> wrote:

> On 09/26/2018 12:50 PM, Joseph Myers wrote:
> > On Wed, 26 Sep 2018, Cesar Philippidis wrote:
> >   
> >> Attached is an old patch which updated the C and C++ FEs to use
> >> %<)%> for the right ')' symbol. It's mostly a cosmetic change. All
> >> of the changes are self-contained to the OpenACC code path.  
> > 
> > Why is the "before ')'" included in the call to c_parser_error at
> > all? c_parser_error calls c_parse_error which adds its own " before
> > " and token description or expansion, so I'd expect the current
> > error to result in a message ending in something of the form
> > "before X before Y".  

> Julian, I need to start working on deep copy in OpenACC. Can you take
> over this patch? The error handling code in the C FE needs to be
> removed because it's dead.

I agree that the error-handling path in question in the C FE is dead.
The difference is that in C, c_parser_oacc_wait_list parses the open
parenthesis, the list and then the close parenthesis separately, and so
a token sequence like:

   (1

will return an expression list of length 1. In the C++ FE rather, a
cp_parser_parenthesized_expression_list is parsed all in one go, and if
the input is not that well-formed sequence then NULL is returned (or a
zero-length vector for an empty list).

But for C, it does not appear that c_parser_expr_list has a code path
that can return a zero-length list at all. So, we can elide the
diagnostic with no change to compiler behaviour. This patch does that,
and also changes the C++ diagnostic, leading to errors being reported
like:

diag.c: In function 'int main(int, char*)':
diag.c:6:59: error: expected ')' before end of line
6 | #pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait (1
  |                                                         ~ ^
  |                                                           )
diag.c:6:59: error: expected integer expression list before end of line 

Actually I'm not too sure how useful the second error line is. Maybe we
should just remove it to improve consistency between C & C++?

The attached has been tested with offloading to nvptx and bootstrapped.
OK?

Thanks,

Julian

2018-XX-YY  James Norris  <jnorris@codesourcery.com>
	    Cesar Philippidis  <cesar@codesourcery.com>
            Julian Brown  <julian@codesourcery.com>

	gcc/c/
	* c-parser.c (c_parser_oacc_wait_list): Remove dead diagnostic
	code.

        gcc/cp/
        * parser.c (cp_parser_oacc_wait_list): Change error message.

	gcc/testsuite/
        * c-c++-common/goacc/asyncwait-1: Update expected errors.
commit 3a59bdbccc3c2383c0056c74797d698c7d81dce2
Author: Julian Brown <julian@codesourcery.com>
Date:   Fri Sep 28 05:52:55 2018 -0700

    OpenACC wait list diagnostic change

diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 1f173fc..92a8089 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -11597,14 +11597,6 @@ c_parser_oacc_wait_list (c_parser *parser, location_t clause_loc, tree list)
     return list;
 
   args = c_parser_expr_list (parser, false, true, NULL, NULL, NULL, NULL);
-
-  if (args->length () == 0)
-    {
-      c_parser_error (parser, "expected integer expression before ')'");
-      release_tree_vector (args);
-      return list;
-    }
-
   args_tree = build_tree_list_vec (args);
 
   for (t = args_tree; t; t = TREE_CHAIN (t))
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 6696f17..43128e0 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -32086,7 +32086,7 @@ cp_parser_oacc_wait_list (cp_parser *parser, location_t clause_loc, tree list)
 
   if (args == NULL || args->length () == 0)
     {
-      cp_parser_error (parser, "expected integer expression before ')'");
+      cp_parser_error (parser, "expected integer expression list");
       if (args != NULL)
 	release_tree_vector (args);
       return list;
diff --git a/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c b/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
index e1840af..2fc8948 100644
--- a/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
+++ b/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
@@ -116,7 +116,7 @@ f (int N, float *a, float *b)
     }
 
 #pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait (1 /* { dg-error "expected '\\\)' before end of line" } */
-    /* { dg-error "expected integer expression before '\\\)'" "" { target c++ } .-1 } */
+    /* { dg-error "expected integer expression list before" "" { target c++ } .-1 } */
     {
         for (ii = 0; ii < N; ii++)
             b[ii] = a[ii];
@@ -171,7 +171,7 @@ f (int N, float *a, float *b)
 #pragma acc wait (1,2,,) /* { dg-error "expected (primary-|)expression before" } */
 
 #pragma acc wait (1 /* { dg-error "expected '\\\)' before end of line" } */
-    /* { dg-error "expected integer expression before '\\\)'" "" { target c++ } .-1 } */
+    /* { dg-error "expected integer expression list before" "" { target c++ } .-1 } */
 
 #pragma acc wait (1,*) /* { dg-error "expected (primary-|)expression before" } */

On Fri, 28 Sep 2018 14:17:42 +0100
Julian Brown <julian@codesourcery.com> wrote:

> On Wed, 26 Sep 2018 14:08:37 -0700
> Cesar Philippidis <cesar@codesourcery.com> wrote:
> 
> > On 09/26/2018 12:50 PM, Joseph Myers wrote:  
> > > On Wed, 26 Sep 2018, Cesar Philippidis wrote:
> > >     
> > >> Attached is an old patch which updated the C and C++ FEs to use
> > >> %<)%> for the right ')' symbol. It's mostly a cosmetic change.
> > >> All of the changes are self-contained to the OpenACC code
> > >> path.    
> > > 
> > > Why is the "before ')'" included in the call to c_parser_error at
> > > all? c_parser_error calls c_parse_error which adds its own "
> > > before " and token description or expansion, so I'd expect the
> > > current error to result in a message ending in something of the
> > > form "before X before Y".    
> 
> > Julian, I need to start working on deep copy in OpenACC. Can you
> > take over this patch? The error handling code in the C FE needs to
> > be removed because it's dead.  
> 
> I agree that the error-handling path in question in the C FE is dead.
> The difference is that in C, c_parser_oacc_wait_list parses the open
> parenthesis, the list and then the close parenthesis separately, and
> so a token sequence like:
> 
>    (1
> 
> will return an expression list of length 1. In the C++ FE rather, a
> cp_parser_parenthesized_expression_list is parsed all in one go, and
> if the input is not that well-formed sequence then NULL is returned
> (or a zero-length vector for an empty list).
> 
> But for C, it does not appear that c_parser_expr_list has a code path
> that can return a zero-length list at all. So, we can elide the
> diagnostic with no change to compiler behaviour. This patch does that,
> and also changes the C++ diagnostic, leading to errors being reported
> like:
> 
> diag.c: In function 'int main(int, char*)':
> diag.c:6:59: error: expected ')' before end of line
> 6 | #pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait (1
>   |                                                         ~ ^
>   |                                                           )
> diag.c:6:59: error: expected integer expression list before end of
> line 
> 
> Actually I'm not too sure how useful the second error line is. Maybe
> we should just remove it to improve consistency between C & C++?
> 
> The attached has been tested with offloading to nvptx and
> bootstrapped. OK?

Ping?

Thanks,

Julian

On Thu, 29 Nov 2018, Julian Brown wrote:

> > But for C, it does not appear that c_parser_expr_list has a code path
> > that can return a zero-length list at all. So, we can elide the
> > diagnostic with no change to compiler behaviour. This patch does that,
> > and also changes the C++ diagnostic, leading to errors being reported
> > like:

The c-parser.c change is OK.

Hi Julian!

On Fri, 28 Sep 2018 14:17:42 +0100, Julian Brown <julian@codesourcery.com> wrote:
> On Wed, 26 Sep 2018 14:08:37 -0700
> Cesar Philippidis <cesar@codesourcery.com> wrote:
> 
> > On 09/26/2018 12:50 PM, Joseph Myers wrote:
> > > On Wed, 26 Sep 2018, Cesar Philippidis wrote:
> > >   
> > >> Attached is an old patch which updated the C and C++ FEs to use
> > >> %<)%> for the right ')' symbol. It's mostly a cosmetic change. All
> > >> of the changes are self-contained to the OpenACC code path.  
> > > 
> > > Why is the "before ')'" included in the call to c_parser_error at
> > > all? c_parser_error calls c_parse_error which adds its own " before
> > > " and token description or expansion, so I'd expect the current
> > > error to result in a message ending in something of the form
> > > "before X before Y".  
> 
> > Julian, I need to start working on deep copy in OpenACC. Can you take
> > over this patch? The error handling code in the C FE needs to be
> > removed because it's dead.
> 
> I agree that the error-handling path in question in the C FE is dead.
> The difference is that in C, c_parser_oacc_wait_list parses the open
> parenthesis, the list and then the close parenthesis separately, and so
> a token sequence like:
> 
>    (1
> 
> will return an expression list of length 1. In the C++ FE rather, a
> cp_parser_parenthesized_expression_list is parsed all in one go, and if
> the input is not that well-formed sequence then NULL is returned (or a
> zero-length vector for an empty list).
> 
> But for C, it does not appear that c_parser_expr_list has a code path
> that can return a zero-length list at all.

In addition to your "(1" token sequence (and similar ones), I suppose
what these code paths in C and C++ are supposed to catch the "wait ()"
case (see line 149 of gcc/testsuite/c-c++-common/goacc/asyncwait-1.c).

I suppose in C, we do diagnose an "error: expected expression before ')'
token" in "c_parser_expr_list"/"c_parser_expr_no_commas", and then return
a list with an "error_mark_node", right?  (I have not verified that.)

> So, we can elide the
> diagnostic with no change to compiler behaviour.

In that case, yes.

> This patch does that,
> and also changes the C++ diagnostic, leading to errors being reported
> like:
> 
> diag.c: In function 'int main(int, char*)':
> diag.c:6:59: error: expected ')' before end of line
> 6 | #pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait (1
>   |                                                         ~ ^
>   |                                                           )
> diag.c:6:59: error: expected integer expression list before end of line 
> 
> Actually I'm not too sure how useful the second error line is. Maybe we
> should just remove it to improve consistency between C & C++?

Right, one single error diagnostic is enough.

But please make sure that the "wait ()" case continues to be diagnosed
correctly -- similarly to C, I suggest "expected expression before ')'
token" (or whatever is natural to the C++ parser), and then accordingly
tidy up that "dg-error" regular expression on line 149 of
gcc/testsuite/c-c++-common/goacc/asyncwait-1.c.

In C++, this is the case that: "args != NULL && args->length () == 0", I
suppose?  (I have not verified that.)


Oh, and next to "wait ()" please also add test coverage for "wait (".


Grüße
 Thomas


> The attached has been tested with offloading to nvptx and bootstrapped.
> OK?
> 
> Thanks,
> 
> Julian
> 
> 2018-XX-YY  James Norris  <jnorris@codesourcery.com>
> 	    Cesar Philippidis  <cesar@codesourcery.com>
>             Julian Brown  <julian@codesourcery.com>
> 
> 	gcc/c/
> 	* c-parser.c (c_parser_oacc_wait_list): Remove dead diagnostic
> 	code.
> 
>         gcc/cp/
>         * parser.c (cp_parser_oacc_wait_list): Change error message.
> 
> 	gcc/testsuite/
>         * c-c++-common/goacc/asyncwait-1: Update expected errors.
> commit 3a59bdbccc3c2383c0056c74797d698c7d81dce2
> Author: Julian Brown <julian@codesourcery.com>
> Date:   Fri Sep 28 05:52:55 2018 -0700
> 
>     OpenACC wait list diagnostic change
> 
> diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
> index 1f173fc..92a8089 100644
> --- a/gcc/c/c-parser.c
> +++ b/gcc/c/c-parser.c
> @@ -11597,14 +11597,6 @@ c_parser_oacc_wait_list (c_parser *parser, location_t clause_loc, tree list)
>      return list;
>  
>    args = c_parser_expr_list (parser, false, true, NULL, NULL, NULL, NULL);
> -
> -  if (args->length () == 0)
> -    {
> -      c_parser_error (parser, "expected integer expression before ')'");
> -      release_tree_vector (args);
> -      return list;
> -    }
> -
>    args_tree = build_tree_list_vec (args);
>  
>    for (t = args_tree; t; t = TREE_CHAIN (t))
> diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
> index 6696f17..43128e0 100644
> --- a/gcc/cp/parser.c
> +++ b/gcc/cp/parser.c
> @@ -32086,7 +32086,7 @@ cp_parser_oacc_wait_list (cp_parser *parser, location_t clause_loc, tree list)
>  
>    if (args == NULL || args->length () == 0)
>      {
> -      cp_parser_error (parser, "expected integer expression before ')'");
> +      cp_parser_error (parser, "expected integer expression list");
>        if (args != NULL)
>  	release_tree_vector (args);
>        return list;
> diff --git a/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c b/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
> index e1840af..2fc8948 100644
> --- a/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
> +++ b/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
> @@ -116,7 +116,7 @@ f (int N, float *a, float *b)
>      }
>  
>  #pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait (1 /* { dg-error "expected '\\\)' before end of line" } */
> -    /* { dg-error "expected integer expression before '\\\)'" "" { target c++ } .-1 } */
> +    /* { dg-error "expected integer expression list before" "" { target c++ } .-1 } */
>      {
>          for (ii = 0; ii < N; ii++)
>              b[ii] = a[ii];
> @@ -171,7 +171,7 @@ f (int N, float *a, float *b)
>  #pragma acc wait (1,2,,) /* { dg-error "expected (primary-|)expression before" } */
>  
>  #pragma acc wait (1 /* { dg-error "expected '\\\)' before end of line" } */
> -    /* { dg-error "expected integer expression before '\\\)'" "" { target c++ } .-1 } */
> +    /* { dg-error "expected integer expression list before" "" { target c++ } .-1 } */
>  
>  #pragma acc wait (1,*) /* { dg-error "expected (primary-|)expression before" } */
>

On Fri, 30 Nov 2018 16:25:42 +0100
Thomas Schwinge <thomas@codesourcery.com> wrote:

> In addition to your "(1" token sequence (and similar ones), I suppose
> what these code paths in C and C++ are supposed to catch the "wait ()"
> case (see line 149 of gcc/testsuite/c-c++-common/goacc/asyncwait-1.c).
> 
> I suppose in C, we do diagnose an "error: expected expression before
> ')' token" in "c_parser_expr_list"/"c_parser_expr_no_commas", and
> then return a list with an "error_mark_node", right?  (I have not
> verified that.)
> 
> > So, we can elide the
> > diagnostic with no change to compiler behaviour.  
> 
> In that case, yes.

[...]

> Right, one single error diagnostic is enough.
> 
> But please make sure that the "wait ()" case continues to be diagnosed
> correctly -- similarly to C, I suggest "expected expression before ')'
> token" (or whatever is natural to the C++ parser), and then
> accordingly tidy up that "dg-error" regular expression on line 149 of
> gcc/testsuite/c-c++-common/goacc/asyncwait-1.c.
> 
> In C++, this is the case that: "args != NULL && args->length () ==
> 0", I suppose?  (I have not verified that.)
> 
> Oh, and next to "wait ()" please also add test coverage for "wait (".

I've made those changes in the attached, thank you. OK?

Julian

ChangeLog

2018-XX-YY  James Norris  <jnorris@codesourcery.com>
            Cesar Philippidis  <cesar@codesourcery.com>
            Julian Brown  <julian@codesourcery.com>

        gcc/c/
        * c-parser.c (c_parser_oacc_wait_list): Remove dead diagnostic
        code.

        gcc/cp/
        * parser.c (cp_parser_oacc_wait_list): Fix error message and avoid
        duplicate diagnostic.

        gcc/testsuite/
        * c-c++-common/goacc/asyncwait-1: Update expected errors and add a
        test for "wait (".

Reviewed-by: Thomas Schwinge  <thomas@codesourcery.com>
Reviewed-by: Joseph Myers  <joseph@codesourcery.com>
commit e3f9a5935e9ec3062017602a580139a0bccf1f4c
Author: Julian Brown <julian@codesourcery.com>
Date:   Fri Sep 28 05:52:55 2018 -0700

    OpenACC wait list diagnostic change
    
    2018-XX-YY  James Norris  <jnorris@codesourcery.com>
    	    Cesar Philippidis  <cesar@codesourcery.com>
    	    Julian Brown  <julian@codesourcery.com>
    
    	gcc/c/
    	* c-parser.c (c_parser_oacc_wait_list): Remove dead diagnostic
    	code.
    
    	gcc/cp/
    	* parser.c (cp_parser_oacc_wait_list): Fix error message and avoid
    	duplicate diagnostic.
    
    	gcc/testsuite/
    	* c-c++-common/goacc/asyncwait-1: Update expected errors and add a
    	test for "wait (".

diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index afc4071..0d7fcc0 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -11801,14 +11801,6 @@ c_parser_oacc_wait_list (c_parser *parser, location_t clause_loc, tree list)
     return list;
 
   args = c_parser_expr_list (parser, false, true, NULL, NULL, NULL, NULL);
-
-  if (args->length () == 0)
-    {
-      c_parser_error (parser, "expected integer expression before ')'");
-      release_tree_vector (args);
-      return list;
-    }
-
   args_tree = build_tree_list_vec (args);
 
   for (t = args_tree; t; t = TREE_CHAIN (t))
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index ab6d237..ac19cb4 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -32605,9 +32605,11 @@ cp_parser_oacc_wait_list (cp_parser *parser, location_t clause_loc, tree list)
 
   if (args == NULL || args->length () == 0)
     {
-      cp_parser_error (parser, "expected integer expression before ')'");
       if (args != NULL)
-	release_tree_vector (args);
+	{
+	  cp_parser_error (parser, "expected integer expression list");
+	  release_tree_vector (args);
+	}
       return list;
     }
 
diff --git a/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c b/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
index e1840af..2f5d476 100644
--- a/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
+++ b/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
@@ -116,7 +116,6 @@ f (int N, float *a, float *b)
     }
 
 #pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait (1 /* { dg-error "expected '\\\)' before end of line" } */
-    /* { dg-error "expected integer expression before '\\\)'" "" { target c++ } .-1 } */
     {
         for (ii = 0; ii < N; ii++)
             b[ii] = a[ii];
@@ -152,6 +151,12 @@ f (int N, float *a, float *b)
             b[ii] = a[ii];
     }
 
+#pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait ( /* { dg-error "expected (primary-|)expression before" } */
+    {
+        for (ii = 0; ii < N; ii++)
+            b[ii] = a[ii];
+    }
+
 #pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait
     {
         for (ii = 0; ii < N; ii++)
@@ -171,7 +176,6 @@ f (int N, float *a, float *b)
 #pragma acc wait (1,2,,) /* { dg-error "expected (primary-|)expression before" } */
 
 #pragma acc wait (1 /* { dg-error "expected '\\\)' before end of line" } */
-    /* { dg-error "expected integer expression before '\\\)'" "" { target c++ } .-1 } */
 
 #pragma acc wait (1,*) /* { dg-error "expected (primary-|)expression before" } */

Hi Julian!

On Mon, 3 Dec 2018 21:10:50 +0000, Julian Brown <julian@codesourcery.com> wrote:
> On Fri, 30 Nov 2018 16:25:42 +0100
> Thomas Schwinge <thomas@codesourcery.com> wrote:
> > [...]
> 
> I've made those changes in the attached, thank you. OK?

Yes, thanks!


Grüße
 Thomas


> 2018-XX-YY  James Norris  <jnorris@codesourcery.com>
>             Cesar Philippidis  <cesar@codesourcery.com>
>             Julian Brown  <julian@codesourcery.com>
> 
>         gcc/c/
>         * c-parser.c (c_parser_oacc_wait_list): Remove dead diagnostic
>         code.
> 
>         gcc/cp/
>         * parser.c (cp_parser_oacc_wait_list): Fix error message and avoid
>         duplicate diagnostic.
> 
>         gcc/testsuite/
>         * c-c++-common/goacc/asyncwait-1: Update expected errors and add a
>         test for "wait (".
> 
> Reviewed-by: Thomas Schwinge  <thomas@codesourcery.com>
> Reviewed-by: Joseph Myers  <joseph@codesourcery.com>
> commit e3f9a5935e9ec3062017602a580139a0bccf1f4c
> Author: Julian Brown <julian@codesourcery.com>
> Date:   Fri Sep 28 05:52:55 2018 -0700
> 
>     OpenACC wait list diagnostic change
>     
>     2018-XX-YY  James Norris  <jnorris@codesourcery.com>
>     	    Cesar Philippidis  <cesar@codesourcery.com>
>     	    Julian Brown  <julian@codesourcery.com>
>     
>     	gcc/c/
>     	* c-parser.c (c_parser_oacc_wait_list): Remove dead diagnostic
>     	code.
>     
>     	gcc/cp/
>     	* parser.c (cp_parser_oacc_wait_list): Fix error message and avoid
>     	duplicate diagnostic.
>     
>     	gcc/testsuite/
>     	* c-c++-common/goacc/asyncwait-1: Update expected errors and add a
>     	test for "wait (".
> 
> diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
> index afc4071..0d7fcc0 100644
> --- a/gcc/c/c-parser.c
> +++ b/gcc/c/c-parser.c
> @@ -11801,14 +11801,6 @@ c_parser_oacc_wait_list (c_parser *parser, location_t clause_loc, tree list)
>      return list;
>  
>    args = c_parser_expr_list (parser, false, true, NULL, NULL, NULL, NULL);
> -
> -  if (args->length () == 0)
> -    {
> -      c_parser_error (parser, "expected integer expression before ')'");
> -      release_tree_vector (args);
> -      return list;
> -    }
> -
>    args_tree = build_tree_list_vec (args);
>  
>    for (t = args_tree; t; t = TREE_CHAIN (t))
> diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
> index ab6d237..ac19cb4 100644
> --- a/gcc/cp/parser.c
> +++ b/gcc/cp/parser.c
> @@ -32605,9 +32605,11 @@ cp_parser_oacc_wait_list (cp_parser *parser, location_t clause_loc, tree list)
>  
>    if (args == NULL || args->length () == 0)
>      {
> -      cp_parser_error (parser, "expected integer expression before ')'");
>        if (args != NULL)
> -	release_tree_vector (args);
> +	{
> +	  cp_parser_error (parser, "expected integer expression list");
> +	  release_tree_vector (args);
> +	}
>        return list;
>      }
>  
> diff --git a/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c b/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
> index e1840af..2f5d476 100644
> --- a/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
> +++ b/gcc/testsuite/c-c++-common/goacc/asyncwait-1.c
> @@ -116,7 +116,6 @@ f (int N, float *a, float *b)
>      }
>  
>  #pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait (1 /* { dg-error "expected '\\\)' before end of line" } */
> -    /* { dg-error "expected integer expression before '\\\)'" "" { target c++ } .-1 } */
>      {
>          for (ii = 0; ii < N; ii++)
>              b[ii] = a[ii];
> @@ -152,6 +151,12 @@ f (int N, float *a, float *b)
>              b[ii] = a[ii];
>      }
>  
> +#pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait ( /* { dg-error "expected (primary-|)expression before" } */
> +    {
> +        for (ii = 0; ii < N; ii++)
> +            b[ii] = a[ii];
> +    }
> +
>  #pragma acc parallel copyin (a[0:N]) copy (b[0:N]) wait
>      {
>          for (ii = 0; ii < N; ii++)
> @@ -171,7 +176,6 @@ f (int N, float *a, float *b)
>  #pragma acc wait (1,2,,) /* { dg-error "expected (primary-|)expression before" } */
>  
>  #pragma acc wait (1 /* { dg-error "expected '\\\)' before end of line" } */
> -    /* { dg-error "expected integer expression before '\\\)'" "" { target c++ } .-1 } */
>  
>  #pragma acc wait (1,*) /* { dg-error "expected (primary-|)expression before" } */
>