[gcc r11-5000] ipa-cp: One more safe_add (PR 97816)

[Martin Jambor]

https://gcc.gnu.org/g:2e97d6443f0a862ce9b798084499635914e3b8c6

commit r11-5000-g2e97d6443f0a862ce9b798084499635914e3b8c6
Author: Martin Jambor <mjambor@suse.cz>
Date:   Fri Nov 13 18:30:11 2020 +0100

    ipa-cp: One more safe_add (PR 97816)
    
    The new behavior of safe_add triggered an ICE because of one use where
    it had not been used instead of a simple addition.  I'll fix it with the
    following obvious patch so that periodic benchmarkers can continue
    working because a proper fix (see below) will need a review.
    
    The testcase showed me, however, that we can propagate time and cost
    from one lattice to another more than once even when that was not the
    intent.  I'll address that as a follow-up after I verify it does not
    affect the IPA-CP heuristics too much or change the corresponding
    params accordingly.
    
    Bootstrapped and tested on x86_64-linux.
    
    gcc/ChangeLog:
    
    2020-11-13  Martin Jambor  <mjambor@suse.cz>
    
            PR ipa/97816
            * ipa-cp.c (value_topo_info<valtype>::propagate_effects): Use
            safe_add instead of a simple addition.

Diff:
---
 gcc/ipa-cp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c
index f29f2164f4e..c3ee71e16e1 100644
--- a/gcc/ipa-cp.c
+++ b/gcc/ipa-cp.c
@@ -3873,7 +3873,8 @@ value_topo_info<valtype>::propagate_effects ()
       for (val = base; val; val = val->scc_next)
 	{
 	  time = time + val->local_time_benefit + val->prop_time_benefit;
-	  size = safe_add (size, val->local_size_cost + val->prop_size_cost);
+	  size = safe_add (size, safe_add (val->local_size_cost,
+					   val->prop_size_cost));
 	}
 
       for (val = base; val; val = val->scc_next)