[gcc r13-1952] Do not walk equivalence set in path_oracle::killing_def.

[Andrew Macleod]

https://gcc.gnu.org/g:19ffb35d17474bb4dd3eb78963c28d10b5362321

commit r13-1952-g19ffb35d17474bb4dd3eb78963c28d10b5362321
Author: Andrew MacLeod <amacleod@redhat.com>
Date:   Wed Aug 3 13:55:42 2022 -0400

    Do not walk equivalence set in path_oracle::killing_def.
    
    When killing a def in the path ranger, there is no need to walk the set
    of existing equivalences clearing bits.  An equivalence match requires
    that both ssa-names have to be in each others set.  As killing_def
    creates a new empty set contianing only the current def,  it already
    ensures false equivaelnces won't happen.
    
            PR tree-optimization/106514
            * value-relation.cc (path_oracle::killing_def) Do not walk the
              equivalence set clearing bits.

Diff:
---
 gcc/value-relation.cc | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/gcc/value-relation.cc b/gcc/value-relation.cc
index a447021214f..3f0957ccdd6 100644
--- a/gcc/value-relation.cc
+++ b/gcc/value-relation.cc
@@ -1400,16 +1400,7 @@ path_oracle::killing_def (tree ssa)
   unsigned v = SSA_NAME_VERSION (ssa);
 
   bitmap_set_bit (m_killed_defs, v);
-
-  // Walk the equivalency list and remove SSA from any equivalencies.
-  if (bitmap_bit_p (m_equiv.m_names, v))
-    {
-      for (equiv_chain *ptr = m_equiv.m_next; ptr; ptr = ptr->m_next)
-	if (bitmap_bit_p (ptr->m_names, v))
-	  bitmap_clear_bit (ptr->m_names, v);
-    }
-  else
-    bitmap_set_bit (m_equiv.m_names, v);
+  bitmap_set_bit (m_equiv.m_names, v);
 
   // Now add an equivalency with itself so we don't look to the root oracle.
   bitmap b = BITMAP_ALLOC (&m_bitmaps);