In order to match evrp behaviour, adjust POINTER_PLUS_EXPR processing to
handle a zero constant plus something to return the something.
ie
[0, 0] + CONST will now return [CONST, CONST] instead of the
previous behaviour of [1, +INF].
Bootstrapped on x86_64-pc-linux-gnu, no regressions, pushed.
Andrew
2020-10-16 Andrew MacLeod <amacl...@redhat.com>
* range-op.cc (pointer_plus_operator::wi_fold): Make pointer_plus
[0, 0] + const return a [const, const] range.
diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 6108de367ad..9df08a61289 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -3063,6 +3063,14 @@ pointer_plus_operator::wi_fold (irange &r, tree type,
const wide_int &rh_lb,
const wide_int &rh_ub) const
{
+ // Check for [0,0] + const, and simply return the const.
+ if (lh_lb == 0 && lh_ub == 0 && rh_lb == rh_ub)
+ {
+ tree val = wide_int_to_tree (type, rh_lb);
+ r.set (val, val);
+ return;
+ }
+
// For pointer types, we are really only interested in asserting
// whether the expression evaluates to non-NULL.
//
