diff options
Diffstat (limited to 'gcc/c-decl.c')
| -rw-r--r-- | gcc/c-decl.c | 50 |
1 files changed, 32 insertions, 18 deletions
diff --git a/gcc/c-decl.c b/gcc/c-decl.c index d97419d..8868a11 100644 --- a/gcc/c-decl.c +++ b/gcc/c-decl.c @@ -4494,27 +4494,41 @@ grokdeclarator (declarator, declspecs, decl_context, initialized) } } - /* Convert size to index_type, so that if it is a variable - the computations will be done in the proper mode. */ - itype = fold (build (MINUS_EXPR, index_type, - convert (index_type, size), - convert (index_type, size_one_node))); - - /* If that overflowed, the array is too big. - ??? While a size of INT_MAX+1 technically shouldn't cause - an overflow (because we subtract 1), the overflow is recorded - during the conversion to index_type, before the subtraction. - Handling this case seems like an unnecessary complication. */ - if (TREE_OVERFLOW (itype)) + if (integer_zerop (size)) { - error ("size of array `%s' is too large", name); - type = error_mark_node; - continue; + /* A zero-length array cannot be represented with an + unsigned index type, which is what we'll get with + build_index_type. Create a signed range instead. */ + itype = build_range_type (index_type, size, + build_int_2 (-1, -1)); } + else + { + /* Compute the maximum valid index, that is, size - 1. + Do the calculation in index_type, so that if it is + a variable the computations will be done in the + proper mode. */ + itype = fold (build (MINUS_EXPR, index_type, + convert (index_type, size), + convert (index_type, size_one_node))); + + /* If that overflowed, the array is too big. + ??? While a size of INT_MAX+1 technically shouldn't + cause an overflow (because we subtract 1), the overflow + is recorded during the conversion to index_type, before + the subtraction. Handling this case seems like an + unnecessary complication. */ + if (TREE_OVERFLOW (itype)) + { + error ("size of array `%s' is too large", name); + type = error_mark_node; + continue; + } - if (size_varies) - itype = variable_size (itype); - itype = build_index_type (itype); + if (size_varies) + itype = variable_size (itype); + itype = build_index_type (itype); + } } #if 0 |