[PATCH] fold-const: Return corresponding integral type for OFFSET_TYPE in range_check_type [PR101162]

[Jakub Jelinek via Gcc-patches]

Hi!

Andrew's recent r12-1608-g2f1686ff70b25fceb04ca2ffc0a450fb682913ef change
to fail verification on various unary and binary operations with OFFSET_TYPE
revealed that e.g. switchconf happily performs multiplications and additions
in OFFSET_TYPE.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2021-06-22  Jakub Jelinek  <ja...@redhat.com>
            Andrew Pinski  <apin...@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.

--- gcc/fold-const.c.jj 2021-06-14 12:27:18.572411152 +0200
+++ gcc/fold-const.c    2021-06-22 11:06:49.718462451 +0200
@@ -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;
 }
--- gcc/testsuite/g++.dg/opt/pr101162.C.jj      2021-06-22 11:08:11.754359910 
+0200
+++ gcc/testsuite/g++.dg/opt/pr101162.C 2021-06-22 11:07:54.318594243 +0200
@@ -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;
+}

        Jakub