From 2991aa06aaaf87874df8ed1c93a4650dc85c79ec Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Mon, 29 Nov 2021 09:19:34 -0500
Subject: [PATCH 1/2] Always track arguments, even when ignoring equiv params.

To "ignore" ranges from equivalences, we should track the range separately,
but still do the other name processing which determiens if there is a single
name or not for equivalence.  Otherwise we mistakently think we can introduce
an equivalences.

	gcc/
	PR tree-optimization/103440
	* gimple-range-fold.cc (fold_using_range::range_of_phi): Continue
	normal param processing for equiv params.

	gcc/testsuite/
	* gcc.dg/pr103440.c: New.
---
 gcc/gimple-range-fold.cc        | 21 +++++++++------------
 gcc/testsuite/gcc.dg/pr103440.c | 24 ++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 12 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr103440.c

diff --git a/gcc/gimple-range-fold.cc b/gcc/gimple-range-fold.cc
index d66ada5bb7c..58122297c0b 100644
--- a/gcc/gimple-range-fold.cc
+++ b/gcc/gimple-range-fold.cc
@@ -795,20 +795,17 @@ fold_using_range::range_of_phi (irange &r, gphi *phi, fur_source &src)
       // Get the range of the argument on its edge.
       src.get_phi_operand (arg_range, arg, e);
 
-      // Likewise, if the incoming PHI argument is equivalent to this
-      // PHI definition, it provides no new info.  Accumulate these ranges
-      // in case all arguments are equivalences.
-      if (src.query ()->query_relation (e, arg, phi_def, false) == EQ_EXPR)
-	{
-	  single_arg = arg;
-	  equiv_range.union_(arg_range);
-	  continue;
-	}
-
       if (!arg_range.undefined_p ())
 	{
 	  // Register potential dependencies for stale value tracking.
-	  r.union_ (arg_range);
+	  // Likewise, if the incoming PHI argument is equivalent to this
+	  // PHI definition, it provides no new info.  Accumulate these ranges
+	  // in case all arguments are equivalences.
+	  if (src.query ()->query_relation (e, arg, phi_def, false) == EQ_EXPR)
+	    equiv_range.union_(arg_range);
+	  else
+	    r.union_ (arg_range);
+
 	  if (gimple_range_ssa_p (arg) && src.gori ())
 	    src.gori ()->register_dependency (phi_def, arg);
 
@@ -829,7 +826,7 @@ fold_using_range::range_of_phi (irange &r, gphi *phi, fur_source &src)
 
     // If all arguments were equivalences, use the equivalence ranges as no
     // arguments were processed.
-    if (!seen_arg)
+    if (r.undefined_p () && !equiv_range.undefined_p ())
       r = equiv_range;
 
     // If the PHI boils down to a single effective argument, look at it.
diff --git a/gcc/testsuite/gcc.dg/pr103440.c b/gcc/testsuite/gcc.dg/pr103440.c
new file mode 100644
index 00000000000..b97f45cd3ed
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr103440.c
@@ -0,0 +1,24 @@
+/* { dg-do run } */
+/* { dg-options "-Os" } */
+/* { dg-timeout 10 } */
+
+int a, b, c, d, e;
+int main() {
+  int f = 2, g = 1, h = -3;
+L1:
+  c = b ^ 1;
+  if (!f)
+    goto L3;
+  if (d)
+    g = e;
+  f = h;
+  if (!c)
+    goto L1;
+L2:
+  if (g)
+    a = 0;
+L3:
+  if (d == g)
+    goto L2;
+  return 0;
+}
-- 
2.17.2