This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH (3/7)] Widening multiply-and-accumulate pattern matching

On 24/06/11 16:47, Richard Guenther wrote:
>> >  I can certainly add checks to make sure that the skipped operations
>> >  actually don't make any important changes to the value, but do I need to?
> Yes.

Ok, I'll go away and do that then.

BTW, I see useless_type_conversion_p, but that's not quite what I want. 
Is there an equivalent existing function to determine whether a 
conversion changes the logical/arithmetic meaning of a type?

I mean, conversion to a wider mode is not "useless", but it is harmless, 
whereas conversion to a narrower mode may truncate the value.

Andrew
Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]