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| author | Diego Novillo <dnovillo@redhat.com> | 2005-10-01 14:01:10 +0000 |
|---|---|---|
| committer | Diego Novillo <dnovillo@gcc.gnu.org> | 2005-10-01 10:01:10 -0400 |
| commit | c83033e76cb638b1b9a9bfe86b73917c6038584f (patch) | |
| tree | 56d54960a5f3cb32009d25c70337006d490d27a7 /gcc/tree-vrp.c | |
| parent | e82d7e604b1f422979641eae89fcc9a04280dd58 (diff) | |
| download | gcc-c83033e76cb638b1b9a9bfe86b73917c6038584f.zip gcc-c83033e76cb638b1b9a9bfe86b73917c6038584f.tar.gz gcc-c83033e76cb638b1b9a9bfe86b73917c6038584f.tar.bz2 | |
tree-vrp.c (value_inside_range, [...]): Add FIXME note regarding quirky semantics.
* tree-vrp.c (value_inside_range, range_includes_zero_p): Add
FIXME note regarding quirky semantics.
From-SVN: r104860
Diffstat (limited to 'gcc/tree-vrp.c')
| -rw-r--r-- | gcc/tree-vrp.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index 0e5ea09..de7a931 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -564,7 +564,23 @@ compare_values (tree val1, tree val2) /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX), 0 if VAL is not inside VR, - -2 if we cannot tell either way. */ + -2 if we cannot tell either way. + + FIXME, the current semantics of this functions are a bit quirky + when taken in the context of VRP. In here we do not care + about VR's type. If VR is the anti-range ~[3, 5] the call + value_inside_range (4, VR) will return 1. + + This is counter-intuitive in a strict sense, but the callers + currently expect this. They are calling the function + merely to determine whether VR->MIN <= VAL <= VR->MAX. The + callers are applying the VR_RANGE/VR_ANTI_RANGE semantics + themselves. + + This also applies to value_ranges_intersect_p and + range_includes_zero_p. The semantics of VR_RANGE and + VR_ANTI_RANGE should be encoded here, but that also means + adapting the users of these functions to the new semantics. */ static inline int value_inside_range (tree val, value_range_t *vr) @@ -596,7 +612,11 @@ value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1) } -/* Return true if VR includes the value zero, false otherwise. */ +/* Return true if VR includes the value zero, false otherwise. FIXME, + currently this will return false for an anti-range like ~[-4, 3]. + This will be wrong when the semantics of value_inside_range are + modified (currently the users of this function expect these + semantics). */ static inline bool range_includes_zero_p (value_range_t *vr) |