From: Aldy Hernandez <aldyh@redhat.com>
Date: Wed, 20 Jul 2022 18:36:54 +0000 (+0200)
Subject: Allow registering same SSA name relations in oracle.
X-Git-Tag: basepoints/gcc-14~5394
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4a36b4e1fe405fe347d57c39f8e23ac8a6c57263;p=thirdparty%2Fgcc.git

Allow registering same SSA name relations in oracle.

Similarly to what we did for the relation oracle, but for the path
oracle.  This was found while working on frange, where we can test for
x == x while checking for NANness.

Tested on x86-64 Linux.

gcc/ChangeLog:

	* value-relation.cc (value_relation::set_relation): Remove assert.
	(path_oracle::register_relation): Exit when trying to register
	same SSA name relations.
---

diff --git a/gcc/value-relation.cc b/gcc/value-relation.cc
index bd344253af3..a447021214f 100644
--- a/gcc/value-relation.cc
+++ b/gcc/value-relation.cc
@@ -667,8 +667,6 @@ private:
 inline void
 value_relation::set_relation (relation_kind r, tree n1, tree n2)
 {
-  gcc_checking_assert (SSA_NAME_VERSION (n1) != SSA_NAME_VERSION (n2)
-		       || r == VREL_EQ);
   related = r;
   name1 = n1;
   name2 = n2;
@@ -1449,6 +1447,11 @@ void
 path_oracle::register_relation (basic_block bb, relation_kind k, tree ssa1,
 				tree ssa2)
 {
+  // If the 2 ssa_names are the same, do nothing.  An equivalence is implied,
+  // and no other relation makes sense.
+  if (ssa1 == ssa2)
+    return;
+
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
       value_relation vr (k, ssa1, ssa2);