[gimplefe] "Unknown tree: c_maybe_const_expr" error while parsing conditional expression

[Prasad Ghangal]

Hi,

I am trying to replace c_parser_paren_condition (parser) in
c_parser_gimple_if_stmt by c_parser_gimple_paren_condition (parser) as
described in the patch

I am trying test case
void __GIMPLE () foo ()
{
  int a;
bb_2:
  if (a == 2)
    goto bb_3;
  else
    goto bb_4;
bb_3:
  a_2 = 4;
bb_4:
  return;
}

but it fails to parse gimple expression and produces error as
/home/prasad/test3.c: In function ‘foo’:
/home/prasad/test3.c:1:18: error: invalid operands in gimple comparison
 void __GIMPLE () foo ()
                  ^~~
if (<<< Unknown tree: c_maybe_const_expr

  a >>> == 2) goto bb_3; else goto bb_4;
/home/prasad/test3.c:1:18: internal compiler error: verify_gimple failed

I failed to debug where it is setting to C_MAYBE_CONST_EXPR


Thanks,
Prasad

diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 70800a2..9e5152c 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -1425,6 +1425,7 @@ static void c_parser_gimple_switch_stmt (c_parser *, 
gimple_seq *);
 static void c_parser_gimple_return_stmt (c_parser *, gimple_seq *);
 static void c_finish_gimple_return (location_t, tree);
 static c_expr c_parser_parse_ssa_names (c_parser *);
+static tree c_parser_gimple_paren_condition (c_parser *);
 
 /* Parse a translation unit (C90 6.7, C99 6.9).
 
@@ -19025,6 +19026,25 @@ c_parser_gimple_goto_stmt (location_t loc, tree label, 
gimple_seq *seq)
   return;
 }
 
+/* Parse a parenthesized condition */
+
+static tree
+c_parser_gimple_paren_condition (c_parser *parser)
+{
+  c_expr cond;
+  enum tree_code subcode = NOP_EXPR;
+  cond.original_code = ERROR_MARK;
+  cond.original_type = NULL;
+  location_t loc = c_parser_peek_token (parser)->location;
+  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+    return error_mark_node;
+  cond = c_parser_gimple_binary_expression (parser, &subcode);
+  cond = convert_lvalue_to_rvalue (loc, cond, true, true);
+  cond.value = c_objc_common_truthvalue_conversion (loc, cond.value);
+  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  return cond.value;
+}
+
 /* Parse gimple if-else statement */
 
 static void 
@@ -19033,7 +19053,7 @@ c_parser_gimple_if_stmt (c_parser *parser, gimple_seq 
*seq)
   tree cond, t_label, f_label, label;
   location_t loc;
   c_parser_consume_token (parser);
-  cond = c_parser_paren_condition (parser);
+  cond = c_parser_gimple_paren_condition (parser);
 
   if (c_parser_next_token_is_keyword (parser, RID_GOTO))
     {