From 88081d38bd82562b6e2d6a4a275e7f6f2aac3422 Mon Sep 17 00:00:00 2001
From: Aldy Hernandez <aldyh@redhat.com>
Date: Thu, 18 Mar 2021 16:05:27 +0100
Subject: Handle setting of 1-bit anti-ranges uniformly.

	PR tree-optimization/99296
	* value-range.cc (irange::irange_set_1bit_anti_range): New.
	(irange::irange_set_anti_range): Call irange_set_1bit_anti_range
	* value-range.h (irange::irange_set_1bit_anti_range): New.
---
 gcc/value-range.cc | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

(limited to 'gcc/value-range.cc')

diff --git a/gcc/value-range.cc b/gcc/value-range.cc
index 9c42f82..cd21f75 100644
--- a/gcc/value-range.cc
+++ b/gcc/value-range.cc
@@ -185,11 +185,42 @@ irange::irange_set (tree min, tree max)
 }
 
 void
+irange::irange_set_1bit_anti_range (tree min, tree max)
+{
+  tree type = TREE_TYPE (min);
+  gcc_checking_assert (TYPE_PRECISION (type) == 1);
+
+  if (operand_equal_p (min, max))
+    {
+      // Since these are 1-bit quantities, they can only be [MIN,MIN]
+      // or [MAX,MAX].
+      if (vrp_val_is_min (min))
+	min = max = vrp_val_max (type);
+      else
+	min = max = vrp_val_min (type);
+      set (min, max);
+    }
+  else
+    {
+      // The only alternative is [MIN,MAX], which is the empty range.
+      set_undefined ();
+    }
+  if (flag_checking)
+    verify_range ();
+}
+
+void
 irange::irange_set_anti_range (tree min, tree max)
 {
   gcc_checking_assert (!POLY_INT_CST_P (min));
   gcc_checking_assert (!POLY_INT_CST_P (max));
 
+  if (TYPE_PRECISION (TREE_TYPE (min)) == 1)
+    {
+      irange_set_1bit_anti_range (min, max);
+      return;
+    }
+
   // set an anti-range
   tree type = TREE_TYPE (min);
   signop sign = TYPE_SIGN (type);
-- 
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