| Message ID | 20101110132218.GK7991@nightcrawler |
|---|---|
| State | New |
| Headers | show |
On Wed, Nov 10, 2010 at 7:22 AM, Nathan Froyd <froydnj@codesourcery.com> wrote: > On Tue, Nov 09, 2010 at 05:10:20PM -0500, Nathan Froyd wrote: >> Builtin double-precision floating-point constants defined by the >> preprocessor get defined as `((double)VAL)'; this style causes problems >> with -Wold-style-cast. The patch below tweaks the definition of such >> constants to use static_cast when compiling for C++. > > My previous patch was overly complicated. This one is much simpler. > I used a function style cast as suggested by Gabriel, but I am unsure of > whether that is preferred over static_cast. It certainly is simpler -- and does not qualify as `old-style cast' which is what you write in C. The patch is OK with me. If you don't hear objects in the next 24 hours, I would suggest to commit. -- Gaby
diff --git a/gcc/c-family/c-cppbuiltin.c b/gcc/c-family/c-cppbuiltin.c index 7b5a14d..ca77964 100644 --- a/gcc/c-family/c-cppbuiltin.c +++ b/gcc/c-family/c-cppbuiltin.c @@ -657,9 +657,13 @@ c_cpp_builtins (cpp_reader *pfile) /* Cast the double precision constants. This is needed when single precision constants are specified or when pragma FLOAT_CONST_DECIMAL64 is used. The correct result is computed by the compiler when using - macros that include a cast. */ - builtin_define_float_constants ("DBL", "L", "((double)%s)", "", - double_type_node); + macros that include a cast. We use a different cast for C++ to avoid + problems with -Wold-style-cast. */ + builtin_define_float_constants ("DBL", "L", + (c_dialect_cxx () + ? "double(%s)" + : "((double)%s)"), + "", double_type_node); builtin_define_float_constants ("LDBL", "L", "%s", "L", long_double_type_node); diff --git a/gcc/testsuite/g++.dg/pr45038.C b/gcc/testsuite/g++.dg/pr45038.C new file mode 100644 index 0000000..57c0c44 --- /dev/null +++ b/gcc/testsuite/g++.dg/pr45038.C @@ -0,0 +1,9 @@ +// PR preprocessor/45038 +// { dg-do compile } +// { dg-options "-Werror -Wold-style-cast" } + +double f(void) +{ + // We used to produce old-style casts for this. + return __DBL_MIN__; +}