[gcc r11-2951] PR tree-optimization/96818 - cast label range to type of switch operand

[gcc r11-2951] PR tree-optimization/96818 - cast label range to type of switch operand

[Aldy Hernandez]

https://gcc.gnu.org/g:d503cd98713a41aad34ade2b9b0d9973efb21e11

commit r11-2951-gd503cd98713a41aad34ade2b9b0d9973efb21e11
Author: Aldy Hernandez <aldyh@redhat.com>
Date:   Fri Aug 28 18:44:58 2020 +0200

    PR tree-optimization/96818 - cast label range to type of switch operand
    
            PR tree-optimization/96818
            * tree-vrp.c (find_case_label_range): Cast label range to
            type of switch operand.

Diff:
---
 gcc/testsuite/g++.dg/pr96818.C | 28 ++++++++++++++++++++++++++++
 gcc/testsuite/gcc.dg/pr96818.c | 14 ++++++++++++++
 gcc/tree-vrp.c                 |  2 ++
 3 files changed, 44 insertions(+)

diff --git a/gcc/testsuite/g++.dg/pr96818.C b/gcc/testsuite/g++.dg/pr96818.C
new file mode 100644
index 00000000000..134bf8b6980
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr96818.C
@@ -0,0 +1,28 @@
+// { dg-do compile }
+// { dg-options "-O2" }
+
+bool operatorY ();
+
+struct l
+{
+  int m;
+  int k;
+  void n ();
+    l ()
+  {
+    while (operatorY ())
+      switch ((unsigned char) k)
+	case 0:
+	{
+	  n ();
+	  case 1:if (m)
+	    ;
+	}
+  }
+};
+
+void
+p ()
+{
+  l ();
+}
diff --git a/gcc/testsuite/gcc.dg/pr96818.c b/gcc/testsuite/gcc.dg/pr96818.c
new file mode 100644
index 00000000000..ea2ac540d39
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr96818.c
@@ -0,0 +1,14 @@
+// { dg-do compile }
+// { dg-options "-O2" }
+
+int a, b, c;
+void d() {
+  unsigned short e;
+  while (b)
+    ;
+  e = (e + 5) / a;
+  switch (e)
+  case 0:
+  case 3:
+    c = a;
+}
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 8c1a1854daa..a165164bb40 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -3850,6 +3850,8 @@ find_case_label_range (gswitch *switch_stmt, const irange *range_of_op)
       if (!case_high)
 	case_high = CASE_LOW (max_label);
       widest_irange label_range (CASE_LOW (min_label), case_high);
+      if (!types_compatible_p (label_range.type (), range_of_op->type ()))
+	range_cast (label_range, range_of_op->type ());
       label_range.intersect (range_of_op);
       if (label_range.undefined_p ())
 	return gimple_switch_label (switch_stmt, 0);