[gcc r13-8560] c++: ICE with scoped enum in switch condition [PR103825]

[Marek Polacek via Gcc-cvs]

https://gcc.gnu.org/g:22510e4a68aa9ca850db34ae62c21c58442d8ab3

commit r13-8560-g22510e4a68aa9ca850db34ae62c21c58442d8ab3
Author: Marek Polacek <pola...@redhat.com>
Date:   Fri Mar 29 16:59:37 2024 -0400

    c++: ICE with scoped enum in switch condition [PR103825]
    
    Here we ICE when gimplifying
    
      enum class Type { Pawn };
      struct Piece {
        Type type : 4;
      };
      void foo() {
        switch (Piece().type)
          case Type::Pawn:;
      }
    
    because we ended up with TYPE_PRECISION (cond) < TYPE_PRECISION (case).
    That's because the case expr type here is the unlowered type Type,
    whereas the conditional's type is the lowered <unnamed-signed:4>.  This
    is not supposed to happen: see the comment in pop_switch around the
    is_bitfield_expr_with_lowered_type check.
    
    But here we did not revert to the lowered SWITCH_STMT_TYPE, because
    the conditional contains a TARGET_EXPR, which has side-effects, which
    means that finish_switch_cond -> maybe_cleanup_point_expr wraps it
    in a CLEANUP_POINT_EXPR.  And is_bitfield_expr_with_lowered_type does
    not see through those.
    
            PR c++/103825
    
    gcc/cp/ChangeLog:
    
            * typeck.cc (is_bitfield_expr_with_lowered_type): Handle
            CLEANUP_POINT_EXPR.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/cpp0x/enum44.C: New test.
    
    (cherry picked from commit daa2e7c7ffe49b788357f7f2c9ef1c9b125c1f8c)

Diff:
---
 gcc/cp/typeck.cc                    |  1 +
 gcc/testsuite/g++.dg/cpp0x/enum44.C | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 56bb21ab251..81bc9edd955 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -2400,6 +2400,7 @@ is_bitfield_expr_with_lowered_type (const_tree exp)
     case NEGATE_EXPR:
     case NON_LVALUE_EXPR:
     case BIT_NOT_EXPR:
+    case CLEANUP_POINT_EXPR:
       return is_bitfield_expr_with_lowered_type (TREE_OPERAND (exp, 0));
 
     case COMPONENT_REF:
diff --git a/gcc/testsuite/g++.dg/cpp0x/enum44.C 
b/gcc/testsuite/g++.dg/cpp0x/enum44.C
new file mode 100644
index 00000000000..92408c92217
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/enum44.C
@@ -0,0 +1,30 @@
+// PR c++/103825
+// { dg-do compile { target c++11 } }
+
+enum class Type { Pawn };
+struct Piece {
+  Type type : 4;
+};
+
+void
+foo ()
+{
+  switch (Piece().type)
+    case Type::Pawn:;
+
+  auto x = Piece().type;
+  switch (x)
+    case Type::Pawn:;
+}
+
+enum class En {A};
+struct St {En field :1;};
+
+void
+bar ()
+{
+  volatile St s = {En::A};
+  switch(s.field) {
+    case En::A : break;
+  }
+}