PR2919: __builtin_types_compatible_p strips CRV qualifiers.

llvm-svn: 58079

3 files changed, 19 insertions, 2 deletions

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 6e62d09474c..c20ca25f283 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -717,7 +717,13 @@ bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx,
   case TypesCompatibleExprClass: {
     const TypesCompatibleExpr *TCE = cast<TypesCompatibleExpr>(this);
     Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
-    Result = Ctx.typesAreCompatible(TCE->getArgType1(), TCE->getArgType2());
+    // Per gcc docs "this built-in function ignores top level
+    // qualifiers".  We need to use the canonical version to properly
+    // be able to strip CRV qualifiers from the type.
+    QualType T0 = Ctx.getCanonicalType(TCE->getArgType1());
+    QualType T1 = Ctx.getCanonicalType(TCE->getArgType2());
+    Result = Ctx.typesAreCompatible(T0.getUnqualifiedType(), 
+                                    T1.getUnqualifiedType());
     break;
   }
   case CallExprClass: {
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 5bc4170e70a..12010646bce 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -205,7 +205,13 @@ public:
   }
   bool VisitTypesCompatibleExpr(const TypesCompatibleExpr *E) {
     Result.zextOrTrunc(getIntTypeSizeInBits(E->getType()));
-    Result = Info.Ctx.typesAreCompatible(E->getArgType1(), E->getArgType2());
+    // Per gcc docs "this built-in function ignores top level
+    // qualifiers".  We need to use the canonical version to properly
+    // be able to strip CRV qualifiers from the type.
+    QualType T0 = Info.Ctx.getCanonicalType(E->getArgType1());
+    QualType T1 = Info.Ctx.getCanonicalType(E->getArgType2());
+    Result = Info.Ctx.typesAreCompatible(T0.getUnqualifiedType(), 
+                                         T1.getUnqualifiedType());
     return true;
   }
   bool VisitDeclRefExpr(const DeclRefExpr *E);
diff --git a/clang/test/Sema/PR2919-builtin-types-compat-strips-crv.c b/clang/test/Sema/PR2919-builtin-types-compat-strips-crv.c
new file mode 100644
index 00000000000..75d0bdcea64
--- /dev/null
+++ b/clang/test/Sema/PR2919-builtin-types-compat-strips-crv.c
@@ -0,0 +1,5 @@
+typedef struct foo T0;
+typedef const struct foo T1;
+
+int a0[__builtin_types_compatible_p(T0,
+                                    const T1) ? 1 : -1];