From 766075c47db5cc9d04463bfb2219b593bb4263ee Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Sat, 2 Nov 2024 10:26:24 -0400
Subject: [PATCH] Don't call invert on VARYING.

When all cases go to one label and resul in a VARYING value, we can't
invert that value to remove all values from the default case. Simply
check for this case and set the default to UNDEFINED.

	PR tree-optimization/117398
	gcc/
	* gimple-range-edge.cc (gimple_outgoing_range::calc_switch_ranges):
	Check for VARYING and don't call invert () on it.

	gcc/testsuite/
	* gcc.dg/pr117398.c: New.
---
 gcc/gimple-range-edge.cc        | 10 ++++++++--
 gcc/testsuite/gcc.dg/pr117398.c | 17 +++++++++++++++++
 2 files changed, 25 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr117398.c

diff --git a/gcc/gimple-range-edge.cc b/gcc/gimple-range-edge.cc
index e3a197a2293..d2387289ad2 100644
--- a/gcc/gimple-range-edge.cc
+++ b/gcc/gimple-range-edge.cc
@@ -159,8 +159,14 @@ gimple_outgoing_range::calc_switch_ranges (gswitch *sw)
       // Remove the case range from the default case.
       int_range_max def_range (type, low, high);
       range_cast (def_range, type);
-      def_range.invert ();
-      default_range.intersect (def_range);
+      // If all possible values are taken, set default_range to UNDEFINED.
+      if (def_range.varying_p ())
+	default_range.set_undefined ();
+      else
+	{
+	  def_range.invert ();
+	  default_range.intersect (def_range);
+	}
 
       // Create/union this case with anything on else on the edge.
       int_range_max case_range (type, low, high);
diff --git a/gcc/testsuite/gcc.dg/pr117398.c b/gcc/testsuite/gcc.dg/pr117398.c
new file mode 100644
index 00000000000..c43f2a3ed6b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr117398.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int a;
+void c(void);
+int d(_Bool b) {
+  switch (b+0) {
+  case 0:
+    break;
+  case 1:
+    break;
+  default:
+    c();
+  }
+  if (b)
+    return a;
+}