https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70170
--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I think that to fix this, we need to add a new pattern to match.pd that deals
with "(ptr +p off) !=/== 0B". Thus something like:
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2263,6 +2263,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(simplify
(cmp (convert? addr@0) integer_zerop)
(if (tree_single_nonzero_warnv_p (@0, NULL))
+ { constant_boolean_node (cmp == NE_EXPR, type); }))
+
+ (simplify
+ (cmp (pointer_plus (convert? @0) INTEGER_CST@1) integer_zerop)
+ (if (tree_single_nonzero_warnv_p (@0, NULL))
{ constant_boolean_node (cmp == NE_EXPR, type); })))
/* If we have (A & C) == C where C is a power of 2, convert this into
