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| author | Per Bothner <bothner@gcc.gnu.org> | 1993-09-12 23:01:37 -0700 |
|---|---|---|
| committer | Per Bothner <bothner@gcc.gnu.org> | 1993-09-12 23:01:37 -0700 |
| commit | d4c89139666d87afd6544277c7e363716e3d7d9e (patch) | |
| tree | 3228495a06f49761a4990498649e3983a717d15f /gcc | |
| parent | 59b22f6465f0e7bee50b3dc18e97c111a5aa521e (diff) | |
| download | gcc-d4c89139666d87afd6544277c7e363716e3d7d9e.zip gcc-d4c89139666d87afd6544277c7e363716e3d7d9e.tar.gz gcc-d4c89139666d87afd6544277c7e363716e3d7d9e.tar.bz2 | |
(expand_expr, ARRAY_REF): Coerce low_bound to sizetype.
From-SVN: r5313
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/expr.c | 15 |
1 files changed, 13 insertions, 2 deletions
@@ -3889,9 +3889,20 @@ expand_expr (exp, target, tmode, modifier) tree index_type = TREE_TYPE (index); int i; - /* Optimize the special-case of a zero lower bound. */ + /* Optimize the special-case of a zero lower bound. + + We convert the low_bound to sizetype to avoid some problems + with constant folding. (E.g. suppose the lower bound is 1, + and its mode is QI. Without the conversion, (ARRAY + +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1)) + +INDEX), which becomes (ARRAY+255+INDEX). Oops!) + + But sizetype isn't quite right either (especially if + the lowbound is negative). FIXME */ + if (! integer_zerop (low_bound)) - index = fold (build (MINUS_EXPR, index_type, index, low_bound)); + index = fold (build (MINUS_EXPR, index_type, index, + convert (sizetype, low_bound))); if (TREE_CODE (index) != INTEGER_CST || TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST) |