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.

1 files changed, 9 insertions, 12 deletions

diff --git a/gcc/gimple-range-fold.cc b/gcc/gimple-range-fold.cc
index d66ada5..5812229 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.