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| author | Eric Botcazou <ebotcazou@adacore.com> | 2019-10-23 11:34:48 +0000 |
|---|---|---|
| committer | Eric Botcazou <ebotcazou@gcc.gnu.org> | 2019-10-23 11:34:48 +0000 |
| commit | 149a3e4d4e3aacdbfee165f0efea4d6327327265 (patch) | |
| tree | a5e9a1583b05e48192d0ae53cbf87ffd5acdb8a7 /gcc/tree-vrp.c | |
| parent | 8d509fb6686cf55c8a7ff8297ad9d75a719d8fa6 (diff) | |
| download | gcc-149a3e4d4e3aacdbfee165f0efea4d6327327265.zip gcc-149a3e4d4e3aacdbfee165f0efea4d6327327265.tar.gz gcc-149a3e4d4e3aacdbfee165f0efea4d6327327265.tar.bz2 | |
re PR tree-optimization/92131 (incorrect assumption that (ao >= 0) is always false)
PR tree-optimization/92131
* tree-vrp.c (extract_range_from_plus_minus_expr): If the resulting
range would be symbolic, drop to varying for any explicit overflow
in the constant part or if neither range is a singleton.
From-SVN: r277314
Diffstat (limited to 'gcc/tree-vrp.c')
| -rw-r--r-- | gcc/tree-vrp.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index 8d4f16e..ad9be74 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -1652,7 +1652,7 @@ extract_range_from_plus_minus_expr (value_range_base *vr, value_range_kind vr0_kind = vr0.kind (), vr1_kind = vr1.kind (); tree vr0_min = vr0.min (), vr0_max = vr0.max (); tree vr1_min = vr1.min (), vr1_max = vr1.max (); - tree min = NULL, max = NULL; + tree min = NULL_TREE, max = NULL_TREE; /* This will normalize things such that calculating [0,0] - VR_VARYING is not dropped to varying, but is @@ -1715,18 +1715,19 @@ extract_range_from_plus_minus_expr (value_range_base *vr, combine_bound (code, wmin, min_ovf, expr_type, min_op0, min_op1); combine_bound (code, wmax, max_ovf, expr_type, max_op0, max_op1); - /* If we have overflow for the constant part and the resulting - range will be symbolic, drop to VR_VARYING. */ - if (((bool)min_ovf && sym_min_op0 != sym_min_op1) - || ((bool)max_ovf && sym_max_op0 != sym_max_op1)) + /* If the resulting range will be symbolic, we need to eliminate any + explicit or implicit overflow introduced in the above computation + because compare_values could make an incorrect use of it. That's + why we require one of the ranges to be a singleton. */ + if ((sym_min_op0 != sym_min_op1 || sym_max_op0 != sym_max_op1) + && ((bool)min_ovf || (bool)max_ovf + || (min_op0 != max_op0 && min_op1 != max_op1))) { vr->set_varying (expr_type); return; } /* Adjust the range for possible overflow. */ - min = NULL_TREE; - max = NULL_TREE; set_value_range_with_overflow (kind, min, max, expr_type, wmin, wmax, min_ovf, max_ovf); if (kind == VR_VARYING) |