| Message ID | f041b82554fd897f2a609a4d274716ad62d33c66.camel@tugraz.at |
|---|---|
| State | New |
| Headers | show |
| Series | [C] _Generic should not warn in non-active branches [PR68193,PR97100] | expand |
On Fri, 4 Aug 2023, Martin Uecker via Gcc-patches wrote: > Here is a patch to reduce false positives in _Generic. > > Bootstrapped and regression tested on x86_64-linux. > > Martin > > c: _Generic should not warn in non-active branches [PR68193,PR97100] > > To avoid false diagnostics, use c_inhibit_evaluation_warnings when > a generic association is known to match during parsing. We may still > generate false positives if the default branch comes earler than > a specific association that matches. > > PR c/68193 > PR c/97100 > > gcc/c/: > * c-parser.cc (c_parser_generic_selection): Inhibit evaluation > warnings branches that are known not be taken during parsing. > > gcc/testsuite/ChangeLog: > * gcc.dg/pr68193.c: New test. OK.
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc index 24a6eb6e459..d1863b301e0 100644 --- a/gcc/c/c-parser.cc +++ b/gcc/c/c-parser.cc @@ -9350,7 +9350,17 @@ c_parser_generic_selection (c_parser *parser) return error_expr; } + bool match = assoc.type == NULL_TREE + || comptypes (assoc.type, selector_type); + + if (!match) + c_inhibit_evaluation_warnings++; + assoc.expression = c_parser_expr_no_commas (parser, NULL); + + if (!match) + c_inhibit_evaluation_warnings--; + if (assoc.expression.value == error_mark_node) { c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL); @@ -9387,7 +9397,7 @@ c_parser_generic_selection (c_parser *parser) match_found = associations.length (); } } - else if (comptypes (assoc.type, selector_type)) + else if (match) { if (match_found < 0 || matched_assoc.type == NULL_TREE) { diff --git a/gcc/testsuite/gcc.dg/pr68193.c b/gcc/testsuite/gcc.dg/pr68193.c new file mode 100644 index 00000000000..2267593e363 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr68193.c @@ -0,0 +1,15 @@ +/* pr69193 */ +/* { dg-do compile } */ +/* { dg-options "-Wall" } */ + +int +main (void) +{ + int i = 0; + int j = _Generic (i, + int: 0, + long int: (i = (long int) 9223372036854775808UL)); + return i + j; +} + +
Here is a patch to reduce false positives in _Generic. Bootstrapped and regression tested on x86_64-linux. Martin c: _Generic should not warn in non-active branches [PR68193,PR97100] To avoid false diagnostics, use c_inhibit_evaluation_warnings when a generic association is known to match during parsing. We may still generate false positives if the default branch comes earler than a specific association that matches. PR c/68193 PR c/97100 gcc/c/: * c-parser.cc (c_parser_generic_selection): Inhibit evaluation warnings branches that are known not be taken during parsing. gcc/testsuite/ChangeLog: * gcc.dg/pr68193.c: New test.