r315951 - Make __builtin_types_compatible_p more like GCC's

[George Burgess IV via cfe-commits]

Author: gbiv
Date: Mon Oct 16 15:58:37 2017
New Revision: 315951

URL: http://llvm.org/viewvc/llvm-project?rev=315951&view=rev
Log:
Make __builtin_types_compatible_p more like GCC's

GCC ignore qualifiers on array types. Since we seem to have this
function primarily for GCC compatibility, we should try to match that
behavior.

This also adds a few more test-cases __builtin_types_compatible_p,
which were inspired by GCC's documentation on the builtin.

Modified:
    cfe/trunk/lib/Sema/SemaExprCXX.cpp
    cfe/trunk/test/Parser/builtin_types_compatible.c

Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=315951&r1=315950&r2=315951&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Mon Oct 16 15:58:37 2017
@@ -4824,9 +4824,13 @@ static bool EvaluateBinaryTypeTrait(Sema
   }
   case BTT_IsSame:
     return Self.Context.hasSameType(LhsT, RhsT);
-  case BTT_TypeCompatible:
-    return Self.Context.typesAreCompatible(LhsT.getUnqualifiedType(),
-                                           RhsT.getUnqualifiedType());
+  case BTT_TypeCompatible: {
+    // GCC ignores cv-qualifiers on arrays for this builtin.
+    Qualifiers LhsQuals, RhsQuals;
+    QualType Lhs = Self.getASTContext().getUnqualifiedArrayType(LhsT, LhsQuals);
+    QualType Rhs = Self.getASTContext().getUnqualifiedArrayType(RhsT, RhsQuals);
+    return Self.Context.typesAreCompatible(Lhs, Rhs);
+  }
   case BTT_IsConvertible:
   case BTT_IsConvertibleTo: {
     // C++0x [meta.rel]p4:

Modified: cfe/trunk/test/Parser/builtin_types_compatible.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Parser/builtin_types_compatible.c?rev=315951&r1=315950&r2=315951&view=diff
==============================================================================
--- cfe/trunk/test/Parser/builtin_types_compatible.c (original)
+++ cfe/trunk/test/Parser/builtin_types_compatible.c Mon Oct 16 15:58:37 2017
@@ -41,3 +41,20 @@ static void test()
 
 }
 
+enum E1 { E1Foo };
+enum E2 { E2Foo };
+
+static void testGccCompatibility() {
+  _Static_assert(__builtin_types_compatible_p(const volatile int, int), "");
+  _Static_assert(__builtin_types_compatible_p(int[5], int[]), "");
+  _Static_assert(!__builtin_types_compatible_p(int[5], int[4]), "");
+  _Static_assert(!__builtin_types_compatible_p(int *, int **), "");
+  _Static_assert(!__builtin_types_compatible_p(const int *, int *), "");
+  _Static_assert(!__builtin_types_compatible_p(enum E1, enum E2), "");
+
+  // GCC's __builtin_types_compatible_p ignores qualifiers on arrays.
+  _Static_assert(__builtin_types_compatible_p(const int[4], int[4]), "");
+  _Static_assert(__builtin_types_compatible_p(int[4], const int[4]), "");
+  _Static_assert(__builtin_types_compatible_p(const int[5][4], int[][4]), "");
+  _Static_assert(!__builtin_types_compatible_p(const int(*)[], int(*)[]), "");
+}