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| author | Jakub Jelinek <jakub@redhat.com> | 2020-08-18 07:51:58 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2020-08-18 07:51:58 +0200 |
| commit | 6d42cbe5ad7a7b46437f2576c9920e44dc14b386 (patch) | |
| tree | a779ecc71eda6e6e0af4fdb3d12ff69855e93c5f /gcc/c/c-parser.c | |
| parent | 1bc4e811aa7249ec972ee7ea5b9bb23e8a0cd69e (diff) | |
| download | gcc-6d42cbe5ad7a7b46437f2576c9920e44dc14b386.zip gcc-6d42cbe5ad7a7b46437f2576c9920e44dc14b386.tar.gz gcc-6d42cbe5ad7a7b46437f2576c9920e44dc14b386.tar.bz2 | |
c: Fix -Wunused-but-set-* warning with _Generic [PR96571]
The following testcase shows various problems with -Wunused-but-set*
warnings and _Generic construct. I think it is best to treat the selector
and the ignored expressions as (potentially) read, because when they are
parsed, the vars in there are already marked as TREE_USED.
2020-08-18 Jakub Jelinek <jakub@redhat.com>
PR c/96571
* c-parser.c (c_parser_generic_selection): Change match_found from bool
to int, holding index of the match. Call mark_exp_read on the selector
expression and on expressions other than the selected one.
* gcc.dg/Wunused-var-4.c: New test.
Diffstat (limited to 'gcc/c/c-parser.c')
| -rw-r--r-- | gcc/c/c-parser.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index 7961cbc..a8bc301 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -8686,7 +8686,7 @@ c_parser_generic_selection (c_parser *parser) struct c_expr selector, error_expr; tree selector_type; struct c_generic_association matched_assoc; - bool match_found = false; + int match_found = -1; location_t generic_loc, selector_loc; error_expr.original_code = ERROR_MARK; @@ -8721,6 +8721,7 @@ c_parser_generic_selection (c_parser *parser) c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL); return selector; } + mark_exp_read (selector.value); selector_type = TREE_TYPE (selector.value); /* In ISO C terms, rvalues (including the controlling expression of _Generic) do not have qualified types. */ @@ -8820,18 +8821,18 @@ c_parser_generic_selection (c_parser *parser) if (assoc.type == NULL_TREE) { - if (!match_found) + if (match_found < 0) { matched_assoc = assoc; - match_found = true; + match_found = associations.length (); } } else if (comptypes (assoc.type, selector_type)) { - if (!match_found || matched_assoc.type == NULL_TREE) + if (match_found < 0 || matched_assoc.type == NULL_TREE) { matched_assoc = assoc; - match_found = true; + match_found = associations.length (); } else { @@ -8849,13 +8850,19 @@ c_parser_generic_selection (c_parser *parser) c_parser_consume_token (parser); } + unsigned int ix; + struct c_generic_association *iter; + FOR_EACH_VEC_ELT (associations, ix, iter) + if (ix != (unsigned) match_found) + mark_exp_read (iter->expression.value); + if (!parens.require_close (parser)) { c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL); return error_expr; } - if (!match_found) + if (match_found < 0) { error_at (selector_loc, "%<_Generic%> selector of type %qT is not " "compatible with any association", |