[PATCH] range-op-float: Further foperator_{,not_}equal::fold_range fix

[Jakub Jelinek <jakub@redhat.com>]

On Fri, Mar 31, 2023 at 12:45:10PM +0200, Jakub Jelinek via Gcc-patches wrote:
>    - there is a missing case (not handled in this patch) where both operands
>      are known to be zeros, but not singleton zeros

This patch adds those cases.

Ok for trunk if it passes bootstrap/regtest?

2023-03-31  Jakub Jelinek  <jakub@redhat.com>

	* range-op-float.cc (foperator_equal::fold_range): If at least
	one of the op ranges is not singleton and neither is NaN and all
	4 bounds are zero, return [1, 1].
	(foperator_not_equal::fold_range): In the same case return [0, 0].

--- gcc/range-op-float.cc.jj	2023-03-31 11:23:04.817876083 +0200
+++ gcc/range-op-float.cc	2023-03-31 12:51:34.757480162 +0200
@@ -616,6 +616,13 @@ foperator_equal::fold_range (irange &r,
       else
 	r = range_false (type);
     }
+  else if (real_iszero (&op1.lower_bound ())
+	   && real_iszero (&op1.upper_bound ())
+	   && real_iszero (&op2.lower_bound ())
+	   && real_iszero (&op2.upper_bound ())
+	   && !maybe_isnan (op1, op2))
+    // [-0.0, 0.0] == [-0.0, 0.0] or similar.
+    r = range_true (type);
   else
     {
       // If ranges do not intersect, we know the range is not equal,
@@ -732,6 +739,13 @@ foperator_not_equal::fold_range (irange
       else
 	r = range_true (type);
     }
+  else if (real_iszero (&op1.lower_bound ())
+	   && real_iszero (&op1.upper_bound ())
+	   && real_iszero (&op2.lower_bound ())
+	   && real_iszero (&op2.upper_bound ())
+	   && !maybe_isnan (op1, op2))
+    // [-0.0, 0.0] != [-0.0, 0.0] or similar.
+    r = range_false (type);
   else
     {
       // If ranges do not intersect, we know the range is not equal,


	Jakub