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| author | Aldy Hernandez <aldyh@redhat.com> | 2018-10-03 17:18:52 +0000 |
|---|---|---|
| committer | Aldy Hernandez <aldyh@gcc.gnu.org> | 2018-10-03 17:18:52 +0000 |
| commit | 2e103ae2138ede8a4db831dea30065fe0041bc58 (patch) | |
| tree | 9c8f42c76ec73408b434f5bd911acc33cf70fae6 /gcc | |
| parent | bedf03a298f87b43f02eaee57542fbd10228ec08 (diff) | |
| download | gcc-2e103ae2138ede8a4db831dea30065fe0041bc58.zip gcc-2e103ae2138ede8a4db831dea30065fe0041bc58.tar.gz gcc-2e103ae2138ede8a4db831dea30065fe0041bc58.tar.bz2 | |
tree-vrp.c (extract_range_from_unary_expr): Special case all pointer conversions.
* tree-vrp.c (extract_range_from_unary_expr): Special case all
pointer conversions.
Do not do anything special for anti-ranges.
From-SVN: r264815
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/tree-vrp.c | 28 |
2 files changed, 21 insertions, 13 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f17bee7..6acb077 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2018-10-3 Aldy Hernandez <aldyh@redhat.com> + + * tree-vrp.c (extract_range_from_unary_expr): Special case all + pointer conversions. + Do not do anything special for anti-ranges. + 2018-10-03 Jérôme Lambourg <lambourg@adacore.com> * config/arm/vxworks.h (ARM_TARGET2_DWARF_FORMAT): Adjust to diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index f95437b..005fc2f 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -1800,9 +1800,14 @@ extract_range_from_unary_expr (value_range *vr, tree inner_type = op0_type; tree outer_type = type; - /* If the expression evaluates to a pointer, we are only interested in - determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */ - if (POINTER_TYPE_P (type)) + /* If the expression involves a pointer, we are only interested in + determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). + + This may lose precision when converting (char *)~[0,2] to + int, because we'll forget that the pointer can also not be 1 + or 2. In practice we don't care, as this is some idiot + storing a magic constant to a pointer. */ + if (POINTER_TYPE_P (type) || POINTER_TYPE_P (op0_type)) { if (!range_includes_zero_p (&vr0)) set_value_range_to_nonnull (vr, type); @@ -1813,15 +1818,12 @@ extract_range_from_unary_expr (value_range *vr, return; } - /* We normalize everything to a VR_RANGE, but for constant - anti-ranges we must handle them by leaving the final result - as an anti range. This allows us to convert things like - ~[0,5] seamlessly. */ - value_range_type vr_type = VR_RANGE; - if (vr0.type == VR_ANTI_RANGE - && TREE_CODE (vr0.min) == INTEGER_CST - && TREE_CODE (vr0.max) == INTEGER_CST) - vr_type = VR_ANTI_RANGE; + /* The POINTER_TYPE_P code above will have dealt with all + pointer anti-ranges. Any remaining anti-ranges at this point + will be integer conversions from SSA names that will be + normalized into VARYING. For instance: ~[x_55, x_55]. */ + gcc_assert (vr0.type != VR_ANTI_RANGE + || TREE_CODE (vr0.min) != INTEGER_CST); /* NOTES: Previously we were returning VARYING for all symbolics, but we can do better by treating them as [-MIN, +MAX]. For @@ -1844,7 +1846,7 @@ extract_range_from_unary_expr (value_range *vr, { tree min = wide_int_to_tree (outer_type, wmin); tree max = wide_int_to_tree (outer_type, wmax); - set_and_canonicalize_value_range (vr, vr_type, min, max, NULL); + set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL); } else set_value_range_to_varying (vr); |