Patchwork [google/gcc-4_8] Port -Wreal-conversion warning

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Submitter Sharad Singhai
Date June 25, 2013, 1:08 a.m.
Message ID <CAKxPW67R7Uu1FekmtNO7-8H+7bb-4dAQYMQMhECLC9KURbdj+w@mail.gmail.com>
Download mbox | patch
Permalink /patch/253995/
State New
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Comments

Sharad Singhai - June 25, 2013, 1:08 a.m.
Hi,

This patch forward ports the -Wreal-conversion warning to
google/gcc-4_8 branch (google ref 39133-p2). I tweaked the patch a
little bit to avoid printing duplicate warnings when both -Wconversion
and -Wreal-conversion are specified. Also, I trimmed the test case to
avoid testing for integer-to-integer narrowing conversions as this
warning is about real conversions.

Bootstrapped and tested on x86_64. Okay for google/gcc-4_8?

Thanks,
Sharad

2013-06-24    <lcwu@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.
Xinliang David Li - June 25, 2013, 4:14 a.m.
To avoid printing twice, can you just do

opt_type = (warn_conversion ? OPT_Wconversion : OPT_Wreal_conversion);
warning_at (loc, opt_type, ...);

David

On Mon, Jun 24, 2013 at 6:08 PM, Sharad Singhai <singhai@google.com> wrote:
> Hi,
>
> This patch forward ports the -Wreal-conversion warning to
> google/gcc-4_8 branch (google ref 39133-p2). I tweaked the patch a
> little bit to avoid printing duplicate warnings when both -Wconversion
> and -Wreal-conversion are specified. Also, I trimmed the test case to
> avoid testing for integer-to-integer narrowing conversions as this
> warning is about real conversions.
>
> Bootstrapped and tested on x86_64. Okay for google/gcc-4_8?
>
> Thanks,
> Sharad
>
> 2013-06-24    <lcwu@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: 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 +1,23 @@
> +// { 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 = 3.2;
> +  float f;
> +  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" }
> +  int q;
> +  q = func3();        // { dg-warning "conversion to" }
> +}
> 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 +1,24 @@
> +// { 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 = 3.2;
> +  float f;
> +  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" }
> +  int q;
> +  q = func3();        // { dg-warning "conversion to" }
> +}
> Index: doc/invoke.texi
> ===================================================================
> --- doc/invoke.texi (revision 200359)
> +++ doc/invoke.texi (working copy)
> @@ -193,7 +193,7 @@ in the following sections.
>  -fno-default-inline  -fvisibility-inlines-hidden @gol
>  -fvisibility-ms-compat @gol
>  -fext-numeric-literals @gol
> --Wabi  -Wconversion-null  -Wctor-dtor-privacy @gol
> +-Wabi  -Wconversion-null -Wctor-dtor-privacy @gol
>  -Wdelete-non-virtual-dtor -Wliteral-suffix -Wnarrowing @gol
>  -Wnoexcept -Wnon-virtual-dtor  -Wreorder @gol
>  -Weffc++  -Wstrict-null-sentinel @gol
> @@ -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.
> +
>  @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 200359)
> +++ 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
> +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 200359)
> +++ 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 200359)
> +++ c-family/c-common.c (working copy)
> @@ -2668,7 +2668,7 @@ conversion_warning (tree type, tree expr)
>    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;
>
>    switch (TREE_CODE (expr))
> @@ -2715,9 +2715,17 @@ conversion_warning (tree type, tree expr)
>
>      default: /* 'expr' is not a constant.  */
>        if (unsafe_conversion_p (type, expr, true))
> - warning_at (loc, OPT_Wconversion,
> -    "conversion to %qT from %qT may alter its value",
> -    type, expr_type);
> +      {
> +        /* Do not print the same warning twice. */
> +        bool printed =
> +            warning_at (loc, OPT_Wreal_conversion,
> +                        "conversion to %qT from %qT may alter its value",
> +                        type, expr_type);
> +        if (!printed)
> +          warning_at (loc, OPT_Wconversion,
> +                      "conversion to %qT from %qT may alter its value",
> +                      type, expr_type);
> +      }
>      }
>  }

Patch

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 +1,23 @@ 
+// { 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 = 3.2;
+  float f;
+  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" }
+  int q;
+  q = func3();        // { dg-warning "conversion to" }
+}
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 +1,24 @@ 
+// { 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 = 3.2;
+  float f;
+  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" }
+  int q;
+  q = func3();        // { dg-warning "conversion to" }
+}
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi (revision 200359)
+++ doc/invoke.texi (working copy)
@@ -193,7 +193,7 @@  in the following sections.
 -fno-default-inline  -fvisibility-inlines-hidden @gol
 -fvisibility-ms-compat @gol
 -fext-numeric-literals @gol
--Wabi  -Wconversion-null  -Wctor-dtor-privacy @gol
+-Wabi  -Wconversion-null -Wctor-dtor-privacy @gol
 -Wdelete-non-virtual-dtor -Wliteral-suffix -Wnarrowing @gol
 -Wnoexcept -Wnon-virtual-dtor  -Wreorder @gol
 -Weffc++  -Wstrict-null-sentinel @gol
@@ -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.
+
 @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 200359)
+++ 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
+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 200359)
+++ 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 200359)
+++ c-family/c-common.c (working copy)
@@ -2668,7 +2668,7 @@  conversion_warning (tree type, tree expr)
   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;

   switch (TREE_CODE (expr))
@@ -2715,9 +2715,17 @@  conversion_warning (tree type, tree expr)

     default: /* 'expr' is not a constant.  */
       if (unsafe_conversion_p (type, expr, true))
- warning_at (loc, OPT_Wconversion,
-    "conversion to %qT from %qT may alter its value",
-    type, expr_type);
+      {
+        /* Do not print the same warning twice. */
+        bool printed =
+            warning_at (loc, OPT_Wreal_conversion,
+                        "conversion to %qT from %qT may alter its value",
+                        type, expr_type);
+        if (!printed)
+          warning_at (loc, OPT_Wconversion,
+                      "conversion to %qT from %qT may alter its value",
+                      type, expr_type);
+      }
     }
 }