[committed][PATCH] Avoid references to vrp_equiv_obstack

[committed][PATCH] Avoid references to vrp_equiv_obstack

[Jeff Law]

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This was broken out of the first tree-vrp refactoring patch.  This patch
avoids a couple references to vrp_equiv_obstack.  This makes the
subsequent refactoring work easier.

Richi approved this as part of the larger patch.  But since I had it
pulled out, I'm going to commit it individually.  I'm posting the patch
here for archival purposes.

Bootstrapped and regression tested on x86_64.

Jeff


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commit f5b45b9dac2b7b793998d2b70ce8f5b7a1cffbf4
Author: Jeff Law <law@torsion.usersys.redhat.com>
Date:   Wed Nov 8 11:59:54 2017 -0500

            * tree-vrp.c (set_value_range): Do not reference vrp_equiv_obstack.
            Get it from the existing bitmap instead.
            (vrp_intersect_ranges_1): Likewise.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0dc2057c08d..16bec6ec00b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-11-09  Jeff Law  <law@redhat.com>
+
+	* tree-vrp.c (set_value_range): Do not reference vrp_equiv_obstack.
+	Get it from the existing bitmap instead.
+	(vrp_intersect_ranges_1): Likewise.
+
 2017-11-09  Jakub Jelinek  <jakub@redhat.com>
 
 	* gimple-ssa-store-merging.c (struct store_immediate_info): Add
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 2b7d9622f69..8e86b060ae7 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -272,10 +272,13 @@ set_value_range (value_range *vr, enum value_range_type t, tree min,
   vr->max = max;
 
   /* Since updating the equivalence set involves deep copying the
-     bitmaps, only do it if absolutely necessary.  */
+     bitmaps, only do it if absolutely necessary.
+
+     All equivalence bitmaps are allocated from the same obstack.  So
+     we can use the obstack associated with EQUIV to allocate vr->equiv.  */
   if (vr->equiv == NULL
       && equiv != NULL)
-    vr->equiv = BITMAP_ALLOC (&vrp_equiv_obstack);
+    vr->equiv = BITMAP_ALLOC (equiv->obstack);
 
   if (equiv != vr->equiv)
     {
@@ -8828,7 +8831,9 @@ vrp_intersect_ranges_1 (value_range *vr0, value_range *vr1)
     bitmap_ior_into (vr0->equiv, vr1->equiv);
   else if (vr1->equiv && !vr0->equiv)
     {
-      vr0->equiv = BITMAP_ALLOC (&vrp_equiv_obstack);
+      /* All equivalence bitmaps are allocated from the same obstack.  So
+	 we can use the obstack associated with VR to allocate vr0->equiv.  */
+      vr0->equiv = BITMAP_ALLOC (vr1->equiv->obstack);
       bitmap_copy (vr0->equiv, vr1->equiv);
     }
 }