[gcc r15-4887] Don't call invert on VARYING.

[Andrew Macleod via Gcc-cvs]

https://gcc.gnu.org/g:766075c47db5cc9d04463bfb2219b593bb4263ee

commit r15-4887-g766075c47db5cc9d04463bfb2219b593bb4263ee
Author: Andrew MacLeod <amacl...@redhat.com>
Date:   Sat Nov 2 10:26:24 2024 -0400

    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.

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

diff --git a/gcc/gimple-range-edge.cc b/gcc/gimple-range-edge.cc
index e3a197a2293a..d2387289ad2d 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 000000000000..c43f2a3ed6b3
--- /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;
+}