Do not call range_of_ssa_name_with_loop_info with the loop tree root.

gcc/ChangeLog:

	PR tree-optimization/97396
	* gimple-range.cc (gimple_ranger::range_of_phi): Do not call
	range_of_ssa_name_with_loop_info with the loop tree root.

gcc/testsuite/ChangeLog:

	* gcc.dg/pr97396.c: New test.

gcc/gimple-range.cc

@@ -490,7 +490,7 @@ gimple_ranger::range_of_phi (irange &r, gphi *phi)
     {
       value_range loop_range;
       class loop *l = loop_containing_stmt (phi);
-      if (l)
+      if (l && loop_outer (l))
         {
 	  range_of_ssa_name_with_loop_info (loop_range, phi_def, l, phi);
 	  if (!loop_range.varying_p ())

gcc/testsuite/gcc.dg/pr97396.c

@@ -0,0 +1,23 @@
+// { dg-do compile }
+// { dg-options "-O1 -ftree-vrp" }
+// { dg-additional-options "-m32" { target { i?86-*-* x86_64-*-* } } }
+
+unsigned int
+po (char *os, unsigned int al)
+{
+  for (;;)
+    {
+      int qx = 0;
+
+      while (al < 1)
+        {
+          char *cw;
+
+          cw = os + qx;
+          if (cw)
+            return al + qx;
+
+          qx += sizeof *cw;
+        }
+    }
+}