From c3c1499498ff8f465ec7eacce6681c5c2da03a92 Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Tue, 23 May 2023 15:41:03 -0400
Subject: [PATCH 3/3] Only update global value if it changes.

Do not update and propagate a global value if it hasn't changed.

	PR tree-optimization/109695
	* gimple-range-cache.cc (ranger_cache::get_global_range): Add
	changed param.
	* gimple-range-cache.h (ranger_cache::get_global_range): Ditto.
	* gimple-range.cc (gimple_ranger::range_of_stmt): Pass changed
	flag to set_global_range.
	(gimple_ranger::prefill_stmt_dependencies): Ditto.
---
 gcc/gimple-range-cache.cc | 10 +++++++++-
 gcc/gimple-range-cache.h  |  2 +-
 gcc/gimple-range.cc       |  8 ++++----
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/gcc/gimple-range-cache.cc b/gcc/gimple-range-cache.cc
index db7ee8eab4e..e069241bc9d 100644
--- a/gcc/gimple-range-cache.cc
+++ b/gcc/gimple-range-cache.cc
@@ -992,10 +992,18 @@ ranger_cache::get_global_range (vrange &r, tree name, bool &current_p)
 //  Set the global range of NAME to R and give it a timestamp.
 
 void
-ranger_cache::set_global_range (tree name, const vrange &r)
+ranger_cache::set_global_range (tree name, const vrange &r, bool changed)
 {
   // Setting a range always clears the always_current flag.
   m_temporal->set_always_current (name, false);
+  if (!changed)
+    {
+      // If there are dependencies, make sure this is not out of date.
+      if (!m_temporal->current_p (name, m_gori.depend1 (name),
+				 m_gori.depend2 (name)))
+	m_temporal->set_timestamp (name);
+      return;
+    }
   if (m_globals.set_range (name, r))
     {
       // If there was already a range set, propagate the new value.
diff --git a/gcc/gimple-range-cache.h b/gcc/gimple-range-cache.h
index 946fbc51465..871255a8116 100644
--- a/gcc/gimple-range-cache.h
+++ b/gcc/gimple-range-cache.h
@@ -117,7 +117,7 @@ public:
 
   bool get_global_range (vrange &r, tree name) const;
   bool get_global_range (vrange &r, tree name, bool &current_p);
-  void set_global_range (tree name, const vrange &r);
+  void set_global_range (tree name, const vrange &r, bool changed = true);
 
   void propagate_updated_value (tree name, basic_block bb);
 
diff --git a/gcc/gimple-range.cc b/gcc/gimple-range.cc
index a275c090e4b..4fae3f95e6a 100644
--- a/gcc/gimple-range.cc
+++ b/gcc/gimple-range.cc
@@ -320,8 +320,8 @@ gimple_ranger::range_of_stmt (vrange &r, gimple *s, tree name)
       // Combine the new value with the old value.  This is required because
       // the way value propagation works, when the IL changes on the fly we
       // can sometimes get different results.  See PR 97741.
-      r.intersect (tmp);
-      m_cache.set_global_range (name, r);
+      bool changed = r.intersect (tmp);
+      m_cache.set_global_range (name, r, changed);
       res = true;
     }
 
@@ -393,8 +393,8 @@ gimple_ranger::prefill_stmt_dependencies (tree ssa)
 	      // Make sure we don't lose any current global info.
 	      Value_Range tmp (TREE_TYPE (name));
 	      m_cache.get_global_range (tmp, name);
-	      r.intersect (tmp);
-	      m_cache.set_global_range (name, r);
+	      bool changed = tmp.intersect (r);
+	      m_cache.set_global_range (name, tmp, changed);
 	    }
 	  continue;
 	}
-- 
2.40.1