Ok.
David
On Wed, Jun 26, 2013 at 10:16 PM, Sharad Singhai <sing...@google.com> wrote:
> I reverted the earlier broken patch. I am including an updated patch
> which warns only for real conversion, not for integral conversions. I
> also updated the test case to include an integral conversion (int to
> char) which doesn't emit the warning with the -Wreal-conversion flag.
>
> Bootstrapped and tested on x86_64. Okay for google/gcc-4_8?
>
> Thanks,
> Sharad
>
> 2013-06-26 <l...@google.com>
>
> * doc/invoke.texi: Document new option -Wreal-conversion.
> * c-family/c.opt: Handle new option.
> * c-family/c-opts.c (c_common_post_options): Ditto.
> * c-family/c-common.c (conversion_warning): Ditto.
>
> testsuite/ChangeLog:
>
> * testsuite/gcc.dg/Wreal-conversion-1.c: New test.
> * testsuite/g++.dg/warn/Wreal-conversion-1.C: Ditto.
>
> Index: doc/invoke.texi
> ===================================================================
> --- doc/invoke.texi (revision 200448)
> +++ doc/invoke.texi (working copy)
> @@ -237,7 +237,7 @@ Objective-C and Objective-C++ Dialects}.
> -Wno-attributes -Wno-builtin-macro-redefined @gol
> -Wc++-compat -Wc++11-compat -Wcast-align -Wcast-qual @gol
> -Wchar-subscripts -Wclobbered -Wcomment @gol
> --Wconversion -Wcoverage-mismatch -Wno-cpp -Wno-deprecated @gol
> +-Wconversion -Wreal-conversion -Wcoverage-mismatch -Wno-cpp
> -Wno-deprecated @gol
> -Wno-deprecated-declarations -Wdisabled-optimization @gol
> -Wno-div-by-zero -Wdouble-promotion -Wempty-body -Wenum-compare @gol
> -Wno-endif-labels -Werror -Werror=* @gol
> @@ -4452,6 +4452,12 @@ reference to them. Warnings about conversions betw
> unsigned integers are disabled by default in C++ unless
> @option{-Wsign-conversion} is explicitly enabled.
>
> +@item -Wreal-conversion
> +@opindex Wreal-conversion
> +@opindex Wno-real-conversion
> +Warn for implicit type conversions from real (@code{double} or @code{float})
> +to integral values. This warning is also enabled by @option{-Wconversion}.
> +
> @item -Wno-conversion-null @r{(C++ and Objective-C++ only)}
> @opindex Wconversion-null
> @opindex Wno-conversion-null
> Index: c-family/c.opt
> ===================================================================
> --- c-family/c.opt (revision 200448)
> +++ c-family/c.opt (working copy)
> @@ -677,6 +677,10 @@ Wsign-compare
> C ObjC C++ ObjC++ EnabledBy(Wextra)
> ;
>
> +Wreal-conversion
> +C ObjC C++ ObjC++ Var(warn_real_conversion) Init(-1) Warning
> EnabledBy(Wconversion)
> +Warn for implicit type conversions from real to integral values
> +
> Wsign-conversion
> C ObjC C++ ObjC++ Var(warn_sign_conversion) LangEnabledBy(C ObjC,Wconversion)
> Warn for implicit type conversions between signed and unsigned integers
> Index: c-family/c-opts.c
> ===================================================================
> --- c-family/c-opts.c (revision 200448)
> +++ c-family/c-opts.c (working copy)
> @@ -876,6 +876,12 @@ c_common_post_options (const char **pfilename)
> if (warn_packed_bitfield_compat == -1)
> warn_packed_bitfield_compat = 1;
>
> + /* Enable warning for converting real values to integral values
> + when -Wconversion is specified (unless disabled through
> + -Wno-real-conversion). */
> + if (warn_real_conversion == -1)
> + warn_real_conversion = warn_conversion;
> +
> /* Special format checking options don't work without -Wformat; warn if
> they are used. */
> if (!warn_format)
> Index: c-family/c-common.c
> ===================================================================
> --- c-family/c-common.c (revision 200448)
> +++ c-family/c-common.c (working copy)
> @@ -2665,12 +2665,22 @@ unsafe_conversion_p (tree type, tree expr, bool pr
> static void
> conversion_warning (tree type, tree expr)
> {
> + int warn_option;
> tree expr_type = TREE_TYPE (expr);
> location_t loc = EXPR_LOC_OR_HERE (expr);
>
> - if (!warn_conversion && !warn_sign_conversion)
> + if (!warn_conversion && !warn_sign_conversion && !warn_real_conversion)
> return;
>
> + /* When either type is a floating point type, warn with
> + -Wreal-conversion instead of -Wconversion (-Wreal-conversion is a
> + subset of -Wconversion that only warns for conversions of real
> + types to integral types). */
> + warn_option = (warn_real_conversion
> + && (FLOAT_TYPE_P (type) || FLOAT_TYPE_P (expr_type)))
> + ? OPT_Wreal_conversion
> + : OPT_Wconversion;
> +
> switch (TREE_CODE (expr))
> {
> case EQ_EXPR:
> @@ -2689,14 +2699,14 @@ conversion_warning (tree type, tree expr)
> can hold the values 0 and -1) doesn't lose information - but
> it does change the value. */
> if (TYPE_PRECISION (type) == 1 && !TYPE_UNSIGNED (type))
> - warning_at (loc, OPT_Wconversion,
> + warning_at (loc, warn_option,
> "conversion to %qT from boolean expression", type);
> return;
>
> case REAL_CST:
> case INTEGER_CST:
> if (unsafe_conversion_p (type, expr, true))
> - warning_at (loc, OPT_Wconversion,
> + warning_at (loc, warn_option,
> "conversion to %qT alters %qT constant value",
> type, expr_type);
> return;
> @@ -2715,7 +2725,7 @@ conversion_warning (tree type, tree expr)
>
> default: /* 'expr' is not a constant. */
> if (unsafe_conversion_p (type, expr, true))
> - warning_at (loc, OPT_Wconversion,
> + warning_at (loc, warn_option,
> "conversion to %qT from %qT may alter its value",
> type, expr_type);
> }
> Index: testsuite/g++.dg/warn/Wreal-conversion-1.C
> ===================================================================
> --- testsuite/g++.dg/warn/Wreal-conversion-1.C (revision 0)
> +++ testsuite/g++.dg/warn/Wreal-conversion-1.C (revision 0)
> @@ -0,0 +1,25 @@
> +// { dg-do compile }
> +// { dg-options "-Wreal-conversion" }
> +
> +#include <stddef.h>
> +
> +int func1(int a) {
> + double f = a;
> + return f; // { dg-warning "conversion to" }
> +}
> +
> +double func3();
> +
> +void func2() {
> + double g = 3.14;
> + float f = 1.8f;
> + int t = g; // { dg-warning "conversion to" }
> + bool b = g;
> + int p;
> + p = f; // { dg-warning "conversion to" }
> + func1(g); // { dg-warning "conversion to" }
> + char c = f; // { dg-warning "conversion to" }
> + c = p;
> + int q;
> + q = func3(); // { dg-warning "conversion to" }
> +}
> Index: testsuite/gcc.dg/Wreal-conversion-1.c
> ===================================================================
> --- testsuite/gcc.dg/Wreal-conversion-1.c (revision 0)
> +++ testsuite/gcc.dg/Wreal-conversion-1.c (revision 0)
> @@ -0,0 +1,24 @@
> +// { dg-do compile }
> +// { dg-options "-Wreal-conversion" }
> +
> +#include <stddef.h>
> +
> +int func1(int a) {
> + double f = a;
> + return f; // { dg-warning "conversion to" }
> +}
> +
> +double func3();
> +
> +void func2() {
> + double g = 3.14;
> + float f = 1.8f;
> + int t = g; // { dg-warning "conversion to" }
> + int p;
> + p = f; // { dg-warning "conversion to" }
> + func1(g); // { dg-warning "conversion to" }
> + char c = f; // { dg-warning "conversion to" }
> + c = p;
> + int q;
> + q = func3(); // { dg-warning "conversion to" }
> +}
