From: Diego Novillo Date: Sat, 1 Oct 2005 14:01:10 +0000 (+0000) Subject: tree-vrp.c (value_inside_range, [...]): Add FIXME note regarding quirky semantics. X-Git-Tag: misc/cutover-cvs2svn~373 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c83033e76cb638b1b9a9bfe86b73917c6038584f;p=thirdparty%2Fgcc.git 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 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2971178cb4aa..b644aaa85eff 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2005-10-01 Diego Novillo + + * tree-vrp.c (value_inside_range, range_includes_zero_p): Add + FIXME note regarding quirky semantics. + 2005-10-01 Diego Novillo PR 24141 diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index 0e5ea09b5d58..de7a931cb156 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)