[llvm-commits] [llvm] r51115 - in /llvm/trunk/lib/CodeGen/SelectionDAG: ScheduleDAG.cpp ScheduleDAGRRList.cpp SelectionDAGISel.cpp

[Neil Booth]

Chris Lattner wrote:-

> 
> On May 14, 2008, at 1:51 PM, Dale Johannesen wrote:
> 
> >
> > On May 14, 2008, at 1:43 PM, Chris Lattner wrote:
> >
> >> On May 14, 2008, at 1:07 PM, Evan Cheng wrote:
> >>> URL: http://llvm.org/viewvc/llvm-project?rev=51115&view=rev
> >>> Log:
> >>> Silence some compiler warnings.
> >>
> >> This introduces new compiler warnings "isNew computation has no side
> >> effects".  How about "isNew = isNew;" ?  We use this idiom in other
> >> places,
> >
> >
> > gcc doesn't warn about that, but it should.
> >
> > How about
> > (void)isNew;
> 
> We use "isNew = isNew;" elsewhere... it seems pretty safe and doesn't  
> use gnu extensions.

A reasonable front-end would warn about unused assignments, which

	isNew = isNew;

would trigger in the examples of this thread when the assertion is compiled
out in release mode.

It's a shame GCC doesn't diagnose such things; hopefully clang will!

Neil.