[cfe-commits] r103904 - in /cfe/trunk: lib/AST/ExprConstant.cpp test/CodeGenCXX/references.cpp

[Douglas Gregor]

I am beginning to doubt our decision to inherit ParmVarDecl from VarDecl. 

Sent from my iPhone

On May 16, 2010, at 2:32 AM, Chandler Carruth <chandlerc at gmail.com> wrote:

> Author: chandlerc
> Date: Sun May 16 04:32:51 2010
> New Revision: 103904
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=103904&view=rev
> Log:
> When constant folding reference variables with an initializer to the
> initializer, don't fold paramters. Their initializers are just default
> arguments which can be overridden. This fixes some spectacular regressions due
> to more things making it into the constant folding.
> 
> Modified:
>    cfe/trunk/lib/AST/ExprConstant.cpp
>    cfe/trunk/test/CodeGenCXX/references.cpp
> 
> Modified: cfe/trunk/lib/AST/ExprConstant.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=103904&r1=103903&r2=103904&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/ExprConstant.cpp (original)
> +++ cfe/trunk/lib/AST/ExprConstant.cpp Sun May 16 04:32:51 2010
> @@ -355,6 +355,10 @@
>   } else if (VarDecl* VD = dyn_cast<VarDecl>(E->getDecl())) {
>     if (!VD->getType()->isReferenceType())
>       return Success(E);
> +    // Reference parameters can refer to anything even if they have an
> +    // "initializer" in the form of a default argument.
> +    if (isa<ParmVarDecl>(VD))
> +      return false;
>     // FIXME: Check whether VD might be overridden!
>     if (const Expr *Init = VD->getAnyInitializer())
>       return Visit(const_cast<Expr *>(Init));
> 
> Modified: cfe/trunk/test/CodeGenCXX/references.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/references.cpp?rev=103904&r1=103903&r2=103904&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/references.cpp (original)
> +++ cfe/trunk/test/CodeGenCXX/references.cpp Sun May 16 04:32:51 2010
> @@ -155,3 +155,16 @@
> // CHECK: load
> // CHECK: ret
> const int &f2() { return 0; }
> +
> +// Don't constant fold const reference parameters with default arguments to
> +// their default arguments.
> +namespace N1 {
> +  const int foo = 1;
> +  // CHECK: @_ZN2N14test
> +  int test(const int& arg = foo) {
> +    // Ensure this array is on the stack where we can set values instead of
> +    // being a global constant.
> +    // CHECK: %args_array = alloca
> +    const int* const args_array[] = { &arg };
> +  }
> +}
> 
> 
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