[PATCH] Do not use tree_to_wide_ref that point to a temporary (PR c++/90587).

[Martin Liška]

Hi.

The PR is about use-after-scope issue where:
wi::tree_to_wide_ref andw = wi::to_wide (val) & wi::to_wide (boundary);

The RHS1 and RHS2 will become out-of-scope after operator& returns a reference.
andw.val then points to one of RHS1 or RHS2. So that we end up with an 
use-after-scope.

Patch can bootstrap on x86_64-linux-gnu and survives regression tests.

Ready to be installed?
Thanks,
Martin

gcc/ChangeLog:

2019-05-23  Martin Liska  <mli...@suse.cz>

        PR c++/90587.
        * tree-ssa-uninit.c (value_sat_pred_p): The result of &
        operation points to a temporary (pointed via tree_to_wide_ref)
        that is out of scope after the &.
---
 gcc/tree-ssa-uninit.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)



diff --git a/gcc/tree-ssa-uninit.c b/gcc/tree-ssa-uninit.c
index bc07afe32c8..fe8f8f0bc28 100644
--- a/gcc/tree-ssa-uninit.c
+++ b/gcc/tree-ssa-uninit.c
@@ -1058,7 +1058,7 @@ value_sat_pred_p (tree val, tree boundary, enum tree_code cmpc,
   if (cmpc != BIT_AND_EXPR)
     return is_value_included_in (val, boundary, cmpc);
 
-  wi::tree_to_wide_ref andw = wi::to_wide (val) & wi::to_wide (boundary);
+  wide_int andw = wi::to_wide (val) & wi::to_wide (boundary);
   if (exact_p)
     return andw == wi::to_wide (val);
   else