[gcc r12-1726] fold-const: Return corresponding integral type for OFFSET_TYPE in range_check_type [PR101162]

[Jakub Jelinek <jakub@gcc.gnu.org>]

https://gcc.gnu.org/g:92d9c9e705f039f42734139c233202888d2bf01b

commit r12-1726-g92d9c9e705f039f42734139c233202888d2bf01b
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Jun 22 15:20:14 2021 +0200

    fold-const: Return corresponding integral type for OFFSET_TYPE in range_check_type [PR101162]
    
    Andrew's recent r12-1608-g2f1686ff70b25fceb04ca2ffc0a450fb682913ef change
    to fail verification on various unary and binary operations with OFFSET_TYPE
    revealed that e.g. switchconv happily performs multiplications and additions
    in OFFSET_TYPE.
    
    2021-06-22  Jakub Jelinek  <jakub@redhat.com>
                Andrew Pinski  <apinski@marvell.com>
    
            PR tree-optimization/101162
            * fold-const.c (range_check_type): Handle OFFSET_TYPE like pointer
            types.
    
            * g++.dg/opt/pr101162.C: New test.

Diff:
---
 gcc/fold-const.c                    |  2 +-
 gcc/testsuite/g++.dg/opt/pr101162.C | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 95673d24ed0..0b33ee99a81 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -5360,7 +5360,7 @@ range_check_type (tree etype)
       else
 	return NULL_TREE;
     }
-  else if (POINTER_TYPE_P (etype))
+  else if (POINTER_TYPE_P (etype) || TREE_CODE (etype) == OFFSET_TYPE)
     etype = unsigned_type_for (etype);
   return etype;
 }
diff --git a/gcc/testsuite/g++.dg/opt/pr101162.C b/gcc/testsuite/g++.dg/opt/pr101162.C
new file mode 100644
index 00000000000..40321890bb0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/pr101162.C
@@ -0,0 +1,21 @@
+// PR tree-optimization/101162
+// { dg-do compile }
+// { dg-options "-O2" }
+
+struct A { int i1, i2, i3, i4, i5, i6; };
+
+int A::*
+foo (int i)
+{
+  switch (i)
+    {
+    case 1: return &A::i1;
+    case 2: return &A::i2;
+    case 3: return &A::i3;
+    case 4: return &A::i4;
+    case 5: return &A::i5;
+    case 6: return &A::i6;
+    }
+
+  return 0;
+}