[committed] openmp: Reject invalid forms of C++ #pragma omp atomic compare [PR106448]

[Jakub Jelinek via Gcc-patches]

Hi!

The allowed syntaxes of atomic compare don't allow ()s around the condition
of ?:, but we were accepting it in one case for C++.

Fixed thusly.

Bootstrapped/regtested on x86_64-linux and i686-linux, committed to trunk.

2022-07-29  Jakub Jelinek  <ja...@redhat.com>

        PR c++/106448
        * parser.cc (cp_parser_omp_atomic): For simple cast followed by
        CPP_QUERY token, don't try cp_parser_binary_operation if compare
        is true.

        * c-c++-common/gomp/atomic-32.c: New test.

--- gcc/cp/parser.cc.jj 2022-07-26 10:32:23.557273390 +0200
+++ gcc/cp/parser.cc    2022-07-28 15:12:44.288195066 +0200
@@ -41535,7 +41535,9 @@ restart:
              goto saw_error;
            }
          token = cp_lexer_peek_token (parser->lexer);
-         if (token->type != CPP_SEMICOLON && !cp_tree_equal (lhs, rhs1))
+         if (token->type != CPP_SEMICOLON
+             && (!compare || token->type != CPP_QUERY)
+             && !cp_tree_equal (lhs, rhs1))
            {
              cp_parser_abort_tentative_parse (parser);
              cp_parser_parse_tentatively (parser);
--- gcc/testsuite/c-c++-common/gomp/atomic-32.c.jj      2022-07-28 
15:23:54.567237524 +0200
+++ gcc/testsuite/c-c++-common/gomp/atomic-32.c 2022-07-28 15:25:25.127027325 
+0200
@@ -0,0 +1,14 @@
+/* PR c++/106448 */
+
+int x, expr;
+  
+void
+foo (void)
+{
+  #pragma omp atomic compare
+  x = (expr > x) ? expr : x;   /* { dg-error "invalid (form|operator)" } */
+  #pragma omp atomic compare
+  x = (x < expr) ? expr : x;   /* { dg-error "invalid (form|operator)" } */
+  #pragma omp atomic compare
+  x = (x == expr) ? expr : x;  /* { dg-error "invalid (form|operator)" } */
+}

        Jakub