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| author | Richard Biener <rguenther@suse.de> | 2024-03-19 15:25:16 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2024-03-20 09:16:38 +0100 |
| commit | 6a55e39bdb1fdb570730c08413ebbe744e493411 (patch) | |
| tree | e0acdc9253c93afc2cd5f81018073d6634fd5d93 | |
| parent | 994d8f922b9d88f45775f57a490409ab1c3baf59 (diff) | |
| download | gcc-6a55e39bdb1fdb570730c08413ebbe744e493411.zip gcc-6a55e39bdb1fdb570730c08413ebbe744e493411.tar.gz gcc-6a55e39bdb1fdb570730c08413ebbe744e493411.tar.bz2 | |
middle-end/113396 - int128 array index and value-ranges
The following fixes bogus truncation of a value-range for an int128
array index when computing the maximum extent for a variable array
reference. Instead of possibly slowing things down by using
widest_int the following makes sure the range bounds fit within
the constraints offset_int were designed for.
PR middle-end/113396
* tree-dfa.cc (get_ref_base_and_extent): Use index range
bounds only if they fit within the address-range constraints
of offset_int.
* gcc.dg/torture/pr113396.c: New testcase.
| -rw-r--r-- | gcc/testsuite/gcc.dg/torture/pr113396.c | 19 | ||||
| -rw-r--r-- | gcc/tree-dfa.cc | 6 |
2 files changed, 23 insertions, 2 deletions
diff --git a/gcc/testsuite/gcc.dg/torture/pr113396.c b/gcc/testsuite/gcc.dg/torture/pr113396.c new file mode 100644 index 0000000..585f717 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr113396.c @@ -0,0 +1,19 @@ +/* { dg-do run } */ +/* { dg-require-effective-target int128 } */ + +unsigned char m[] = {5, 79, 79, 79, 79}; +__int128 p; +int main() +{ + int g1 = 0; + p = 0; + for (int aj = 0; aj < 256; aj++) + { + m[0] = -4; + for (; p >= 0; p -= 1) { + g1 = m[p]; + } + } + if (g1 != 0xfc) + __builtin_abort(); +} diff --git a/gcc/tree-dfa.cc b/gcc/tree-dfa.cc index cbd3774..93e53b2 100644 --- a/gcc/tree-dfa.cc +++ b/gcc/tree-dfa.cc @@ -549,7 +549,8 @@ get_ref_base_and_extent (tree exp, poly_int64 *poffset, /* Try to constrain maxsize with range information. */ offset_int omax = offset_int::from (max, TYPE_SIGN (TREE_TYPE (index))); - if (known_lt (lbound, omax)) + if (wi::get_precision (max) <= ADDR_MAX_BITSIZE + && known_lt (lbound, omax)) { poly_offset_int rmaxsize; rmaxsize = (omax - lbound + 1) @@ -567,7 +568,8 @@ get_ref_base_and_extent (tree exp, poly_int64 *poffset, /* Try to adjust bit_offset with range information. */ offset_int omin = offset_int::from (min, TYPE_SIGN (TREE_TYPE (index))); - if (known_le (lbound, omin)) + if (wi::get_precision (min) <= ADDR_MAX_BITSIZE + && known_le (lbound, omin)) { poly_offset_int woffset = wi::sext (omin - lbound, |