ranger: Fix up wi_fold_in_parts for small precision types [PR104334]

The wide-int.h templates expect that when an int/long etc. operand is used
it will be sign-extended based on the types precision.
wi_fold_in_parts passes 3 such non-zero constants to wi::lt_p, wi::gt_p
and wi::eq_p - 1, 3 and 4, which means it was doing weird things if either
some of 1, 3 or 4 weren't representable in type, or if type was unsigned 3 bit
type 4 should be written as -4.
The following patch promotes the subtraction operands to widest_int and
uses that as the type for ?h_range variables and compares them as such.
We don't need the overflow handling because there is never an overflow.

2022-02-02  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/104334
	* range-op.cc (range_operator::wi_fold_in_parts): Change lh_range
	and rh_range type to widest_int and subtract in widest_int.  Remove
	ov_rh, ov_lh and sign vars, always perform comparisons as signed
	and use >, < and == operators for it.

	* g++.dg/opt/pr104334.C: New test.

2 files changed, 50 insertions, 12 deletions

diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 19bdf30..ebc21d6 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -144,22 +144,21 @@ range_operator::wi_fold_in_parts (irange &r, tree type,
 				  const wide_int &rh_lb,
 				  const wide_int &rh_ub) const
 {
-  wi::overflow_type ov_rh, ov_lh;
   int_range_max tmp;
-  wide_int rh_range = wi::sub (rh_ub, rh_lb, TYPE_SIGN (type), &ov_rh);
-  wide_int lh_range = wi::sub (lh_ub, lh_lb, TYPE_SIGN (type), &ov_lh);
-  signop sign = TYPE_SIGN (type);;
+  widest_int rh_range = wi::sub (widest_int::from (rh_ub, TYPE_SIGN (type)),
+				 widest_int::from (rh_lb, TYPE_SIGN (type)));
+  widest_int lh_range = wi::sub (widest_int::from (lh_ub, TYPE_SIGN (type)),
+				 widest_int::from (lh_lb, TYPE_SIGN (type)));
   // If there are 2, 3, or 4 values in the RH range, do them separately.
   // Call wi_fold_in_parts to check the RH side.
-  if (wi::gt_p (rh_range, 0, sign) && wi::lt_p (rh_range, 4, sign)
-      && ov_rh == wi::OVF_NONE)
+  if (rh_range > 0 && rh_range < 4)
     {
       wi_fold_in_parts (r, type, lh_lb, lh_ub, rh_lb, rh_lb);
-      if (wi::gt_p (rh_range, 1, sign))
+      if (rh_range > 1)
 	{
 	  wi_fold_in_parts (tmp, type, lh_lb, lh_ub, rh_lb + 1, rh_lb + 1);
 	  r.union_ (tmp);
-	  if (wi::eq_p (rh_range, 3))
+	  if (rh_range == 3)
 	    {
 	      wi_fold_in_parts (tmp, type, lh_lb, lh_ub, rh_lb + 2, rh_lb + 2);
 	      r.union_ (tmp);
@@ -170,15 +169,14 @@ range_operator::wi_fold_in_parts (irange &r, tree type,
     }
   // Otherise check for 2, 3, or 4 values in the LH range and split them up.
   // The RH side has been checked, so no recursion needed.
-  else if (wi::gt_p (lh_range, 0, sign) && wi::lt_p (lh_range, 4, sign)
-	   && ov_lh == wi::OVF_NONE)
+  else if (lh_range > 0 && lh_range < 4)
     {
       wi_fold (r, type, lh_lb, lh_lb, rh_lb, rh_ub);
-      if (wi::gt_p (lh_range, 1, sign))
+      if (lh_range > 1)
 	{
 	  wi_fold (tmp, type, lh_lb + 1, lh_lb + 1, rh_lb, rh_ub);
 	  r.union_ (tmp);
-	  if (wi::eq_p (lh_range, 3))
+	  if (lh_range == 3)
 	    {
 	      wi_fold (tmp, type, lh_lb + 2, lh_lb + 2, rh_lb, rh_ub);
 	      r.union_ (tmp);
diff --git a/gcc/testsuite/g++.dg/opt/pr104334.C b/gcc/testsuite/g++.dg/opt/pr104334.C
new file mode 100644
index 0000000..8b75b6a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/pr104334.C
@@ -0,0 +1,40 @@
+// PR tree-optimization/104334
+// { dg-do run { target c++11 } }
+// { dg-options "-O2 --param logical-op-non-short-circuit=0" }
+
+enum class A { A0, A1, A2, A3 };
+int x;
+
+__attribute__((noipa)) void
+baz ()
+{
+  x = 1;
+}
+
+struct B {
+  unsigned b : 2;
+
+  A
+  foo () const
+  {
+    return static_cast<A> (b);
+  }
+
+  __attribute__((noinline)) void
+  bar ()
+  {
+    if (foo () == A::A2 || foo () == A::A3)
+      baz ();
+  }
+};
+
+int
+main ()
+{
+  B c;
+  c.b = 2;
+  c.bar ();
+  if (x != 1)
+    __builtin_abort ();
+  return 0;
+}