Bug 152768 – Silence -Wtautological-compare

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Michael Catanzaro]

[394/5657] Building CXX object Source/...vaScriptCore.dir/runtime/Options.cpp.o
../../Source/JavaScriptCore/runtime/Options.cpp:618:217: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:899: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:1584: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:2278: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:2972: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:3657: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:4448: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:5064: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:5758: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:6449: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:7146: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:7882: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:8612: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:9336: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:10033: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:10757: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:11481: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:12175: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:12854: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:13608: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:14332: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:15056: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:15789: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:16483: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:17183: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:17936: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:18549: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:19261: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:19955: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:20682: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:21370: warning: self-comparison always evaluates to true [-Wtautological-compare]
../../Source/JavaScriptCore/runtime/Options.cpp:618:22049: warning: self-comparison always evaluates to true [-Wtautological-compare]
32 warnings generated.

[Michael Catanzaro]

Created attachment 268341 [details]
Patch

[Saam Barati]

Comment on attachment 268341 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=268341&action=review

r=me with build fixes

> Source/JavaScriptCore/runtime/Options.cpp:627
> +#if COMPILER(CLANG)

Shouldn't this be the same condition as above?

[Michael Catanzaro]

(In reply to comment #2)
> > Source/JavaScriptCore/runtime/Options.cpp:627
> > +#if COMPILER(CLANG)
> 
> Shouldn't this be the same condition as above?

Yup.

Also this construct:

#if COMPILER(CLANG) && __has_warning("-Wtautological-compare")

Is breaking the GCC build, it has to be:

#if COMPILER(CLANG)
#if __has_warning("-Wtautological-compare")

Which is a bit annoying... maybe could add some WTF macros to simplify this in a future commit.

[Michael Catanzaro]

Created attachment 268385 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 268385 [details]
Patch

Clearing flags on attachment: 268385

Committed r194659: <http://trac.webkit.org/changeset/194659>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.